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8 Commits
main ... 51780b3a78

Author SHA1 Message Date
Julien THILLARD
51780b3a78 Add more from the std 2026-03-18 14:59:16 +01:00
Julien THILLARD
9413fba265 Add more from the std 2026-03-18 00:25:34 +01:00
Julien THILLARD
fd0770f813 Add more from the std 2026-03-17 23:40:39 +01:00
Julien THILLARD
10be5b301c Add more from the std 2026-03-17 23:34:00 +01:00
Julien THILLARD
72989d86a8 Add more from the std 2026-03-17 22:51:36 +01:00
Julien THILLARD
9958b23c89 Add more from the std 2026-03-17 21:33:34 +01:00
Julien THILLARD
56ad115e58 Add a small part of the real rust std 2026-03-17 20:13:39 +01:00
Julien THILLARD
56a00d0403 Sync computers 2026-03-17 18:29:00 +01:00
233 changed files with 44600 additions and 3130 deletions
Expand all files Collapse all files

2
.cargo/config.toml
View File

@@ -3,6 +3,8 @@ target = "riscv64.json"
[unstable]
json-target-spec = true
build-std = ["core", "compiler_builtins", "alloc"]
build-std-features = ["compiler-builtins-mem"]
[target.riscv64]
rustflags = [

8
.gdbinit
View File

@@ -1,6 +1,6 @@
# file target/riscv64/debug/kernel-rust
file target/riscv64/debug/kernel-rust
target remote localhost:1234
# break machine_mode_entry
break *0x800cfdd8
add-symbol-file target/riscv64/debug/agetty 0x800cfdd8
break machine_mode_entry
# break *0x800bf000
# add-symbol-file target/riscv64/debug/test_pic 0x800bf000
c

3
.gitignore vendored
View File

@@ -7,6 +7,3 @@
disk.img
**/*.mem
mnt
sysroot/lib/rustlib/riscv64
library/alloc

6
Cargo.toml
View File

@@ -1,7 +1,6 @@
[workspace]
resolver = "3"
members = ["crates/ansii","user/*"]
exclude = ["library", "build-tools", "crates/io"]
members = ["crates/bytes-struct","crates/io","crates/std", "crates/shared", "user/*"]
[package]
name = "kernel-rust"
@@ -13,11 +12,10 @@ bitflags = "2"
embedded-alloc = "0.7"
kernel-macros = { path = "crates/kernel-macros" }
bytes-struct = { path = "crates/bytes-struct" }
ansii = { path = "crates/ansii" }
log = "0.4"
critical-section = { version = "1", features = ["restore-state-bool"] }
bffs = { path = "crates/bffs", features = ["alloc"] }
io = { package = "no-std-io", path = "crates/io" }
io = { path = "crates/io", features = ["alloc"] }
shared = { path = "crates/shared", features = ["kernel"] }
goblin = { version = "0.7", default-features = false, features = ["elf32", "elf64", "endian_fd"] }
hashbrown = "0.16"

2
build-tools/.cargo/config.toml
View File

@@ -1,2 +0,0 @@
[build]
target = "x86_64-unknown-linux-gnu"

14
build-tools/Cargo.toml
View File

@@ -1,14 +0,0 @@
[package]
name = "build-tools"
version = "0.1.0"
edition = "2024"
[[bin]]
name = "gen-symbols"
path = "src/gen_symbols.rs"
[dependencies]
rayon = "1.11"
object = "0.32"
addr2line = "0.21"
rustc-demangle = "0.1"

107
build-tools/src/gen_symbols.rs
View File

@@ -1,107 +0,0 @@
use addr2line::Context;
use object::{Object, ObjectSymbol, SymbolKind};
use std::collections::HashMap;
use std::fs::File;
use std::io::{BufWriter, Write};
use std::path::Path;
#[repr(C, packed(4))]
#[derive(Debug)]
struct RawSymbol {
addr: u64,
line: u32,
name_off: u32,
file_off: u32,
}
fn main() -> Result<(), Box<dyn std::error::Error>> {
let elf_path = "../target/riscv64/debug/kernel-rust";
let bin_data = std::fs::read(elf_path)?;
let obj_file = object::File::parse(&*bin_data)?;
let context = Context::new(&obj_file)?;
let mut symbols_list = Vec::new();
let mut string_table = Vec::new();
let mut str_cache = HashMap::new();
// Helper pour gérer la table des chaînes (String Table)
let mut add_string = |s: &str| -> u32 {
*str_cache.entry(s.to_string()).or_insert_with(|| {
let off = string_table.len() as u32;
string_table.extend_from_slice(s.as_bytes());
string_table.push(0); // Null terminator
off
})
};
println!("Extraction des symboles depuis {}...", elf_path);
obj_file.symbols().enumerate().for_each(|(_i, sym)| {
// On ne garde que les fonctions (Text)
if sym.kind() == SymbolKind::Text && sym.size() > 0 {
let addr = sym.address();
let raw_name = sym.name().unwrap_or("unknown");
let name = format!("{:#}", rustc_demangle::demangle(raw_name));
let mut frames = context.find_frames(addr).skip_all_loads().unwrap();
let (file, line) = if let Ok(Some(frame)) = frames.next() {
let f = frame
.location
.as_ref()
.and_then(|l| {
l.file.and_then(|file| {
Path::new(file)
.strip_prefix(std::env::current_dir().unwrap().parent().unwrap())
.map_or(Some(file), |p| p.to_str())
})
})
.unwrap_or("unknown");
let l = frame.location.as_ref().and_then(|l| l.line).unwrap_or(0);
(f, l)
} else {
("unknown", 0)
};
symbols_list.push(RawSymbol {
addr,
line,
name_off: add_string(&name),
file_off: add_string(file),
});
}
});
// Tri par adresse pour la recherche binaire au runtime
symbols_list.sort_by_key(|s| s.addr);
// Écriture du fichier symbols.bin
let mut f = BufWriter::new(File::create("../target/symbols.bin")?);
// Header : [u64: count] [u64: string_table_offset]
let header_size = 16;
let sym_table_size = symbols_list.len() * std::mem::size_of::<RawSymbol>();
f.write_all(&(symbols_list.len() as u64).to_le_bytes())?;
f.write_all(&((header_size + sym_table_size) as u64).to_le_bytes())?;
// Table des symboles
for sym in &symbols_list {
unsafe {
let bytes = std::slice::from_raw_parts(
(sym as *const RawSymbol) as *const u8,
std::mem::size_of::<RawSymbol>(),
);
f.write_all(bytes)?;
}
}
// Table des noms
f.write_all(&string_table)?;
println!(
"Terminé ! {} symboles écrits dans symbols.bin",
symbols_list.len()
);
Ok(())
}

7
crates/ansii/Cargo.toml
View File

@@ -1,7 +0,0 @@
[package]
name = "ansii"
version = "0.1.0"
edition = "2024"
[dependencies]
winnow = { version = "1", default-features = false, features = ["binary", "ascii"] }

66
crates/ansii/src/lib.rs
View File

@@ -1,66 +0,0 @@
#![no_std]
use winnow::Result;
use winnow::ascii::dec_uint;
use winnow::combinator::{alt, preceded, seq};
use winnow::error::ContextError;
use winnow::prelude::*;
pub enum AnsiiEscape {
Color16(ColorPlace, Color16Type, u8),
Color256(u8),
ColorRGB(ColorPlace, u8, u8, u8),
}
pub enum ColorPlace {
Foreground,
Background,
}
pub enum Color16Type {
Normal,
Bold,
Brigth,
}
fn parse_color16(input: &mut &str) -> Result<AnsiiEscape> {
let (c, _) = preceded("[", seq!(dec_uint, "m")).parse_next(input)?;
if c < 30 || c == 38 || c == 48 || c > 49 {
Err(ContextError::new())
} else {
Ok(AnsiiEscape::Color16(
ColorPlace::Foreground,
Color16Type::Normal,
c,
))
}
}
fn parse_color_rgb(input: &mut &str) -> Result<AnsiiEscape> {
let (t, _, r, _, g, _, b, _) = preceded(
"[",
seq!(
alt(("38", "48")),
";",
dec_uint,
";",
dec_uint,
";",
dec_uint,
"m"
),
)
.parse_next(input)?;
Ok(AnsiiEscape::ColorRGB(
if t == "38" {
ColorPlace::Foreground
} else {
ColorPlace::Background
},
r,
g,
b,
))
}
pub fn parse_ansii(input: &mut &str) -> Result<AnsiiEscape> {
alt((parse_color_rgb, parse_color16)).parse_next(input)
}

2
crates/bffs/Cargo.toml
View File

@@ -4,7 +4,7 @@ version = "0.1.0"
edition = "2024"
[dependencies]
io = { package = "no-std-io", path = "../io" }
io = { path = "../io" }
bitflags = "2"
[features]

7
crates/bffs/src/boot_sector.rs
View File

@@ -1,6 +1,5 @@
use io::Read;
use crate::io_ext::ReadLeExt;
use crate::error::Error;
use io::{Read, ReadLeExt};
#[derive(Debug, Clone, Copy)]
pub struct Fat32BootSector {
@@ -95,7 +94,7 @@ impl Fat32BootSector {
}
impl Fat32BootSector {
pub fn deserialize<T: Read>(disk: &mut T) -> Result<Self, io::Error> {
pub fn deserialize<T: Read>(disk: &mut T) -> Result<Self, Error<T::Error>> {
let mut jump_boot = [0u8; _];
disk.read_exact(&mut jump_boot)?;
let mut oem_name = [0u8; _];

30
crates/bffs/src/dir.rs
View File

@@ -1,32 +1,36 @@
use crate::{
Fat32FileSystem, ReadSeek, ReadWriteSeek,
entry::{DirEntry, DirectoryIterator},
error::Error,
file::{File, RawFile},
path::Path,
};
use io::{self, Read, Seek, Write};
use io::{self, IoBase, Read, Seek, Write};
pub struct Dir<'a, T> {
raw: RawFile<'a, T>,
fs: &'a Fat32FileSystem<T>,
}
impl<'a, T: IoBase> IoBase for Dir<'a, T> {
type Error = Error<T::Error>;
}
impl<'a, T: ReadSeek> Seek for Dir<'a, T> {
fn seek(&mut self, pos: io::SeekFrom) -> io::Result<u64> {
fn seek(&mut self, pos: io::SeekFrom) -> Result<u64, Self::Error> {
self.raw.seek(pos)
}
}
impl<'a, T: ReadSeek> Read for Dir<'a, T> {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error> {
self.raw.read(buf)
}
}
impl<'a, T: ReadWriteSeek> Write for Dir<'a, T> {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
self.raw.write(buf)
}
fn flush(&mut self) -> io::Result<()> {
fn flush(&mut self) -> Result<(), Self::Error> {
self.raw.flush()
}
}
@@ -40,7 +44,7 @@ impl<'a, T> Dir<'a, T> {
}
}
impl<'a, T: ReadSeek> Dir<'a, T> {
pub fn open_entry<P: AsRef<Path>>(&self, path: P) -> Result<DirEntry<'a, T>, io::Error> {
pub fn open_entry<P: AsRef<Path>>(&self, path: P) -> Result<DirEntry<'a, T>, Error<T::Error>> {
if path.as_ref().is_absolute() {
return self.fs.open_entry(path);
}
@@ -52,16 +56,16 @@ impl<'a, T: ReadSeek> Dir<'a, T> {
if f.is_dir() {
return f.to_dir().open_entry(entry_name);
} else {
return Err(io::Error::from(io::ErrorKind::NotFound));
return Err(Error::NotFound);
}
} else {
return Ok(f);
}
}
}
Err(io::Error::from(io::ErrorKind::NotFound))
Err(Error::NotFound)
}
pub fn open_file<P: AsRef<Path>>(&self, path: P) -> Result<File<'a, T>, io::Error> {
pub fn open_file<P: AsRef<Path>>(&self, path: P) -> Result<File<'a, T>, Error<T::Error>> {
if path.as_ref().is_absolute() {
return self.fs.open_file(path);
}
@@ -70,19 +74,19 @@ impl<'a, T: ReadSeek> Dir<'a, T> {
match dirname {
Some(name) => {
if !entry.is_dir() {
return Err(io::Error::from(io::ErrorKind::NotFound));
return Err(Error::NotFound);
}
entry.to_dir().open_file(name)
}
None => {
if !entry.is_file() {
return Err(io::Error::from(io::ErrorKind::NotFound));
return Err(Error::NotFound);
}
Ok(entry.to_file())
}
}
}
pub fn open_dir<P: AsRef<Path>>(&self, path: P) -> Result<Self, io::Error> {
pub fn open_dir<P: AsRef<Path>>(&self, path: P) -> Result<Self, Error<T::Error>> {
let path = path.as_ref();
if path.is_absolute() {
return self.fs.open_dir(path);
@@ -90,7 +94,7 @@ impl<'a, T: ReadSeek> Dir<'a, T> {
let (start, dirname) = path.split_path();
let entry = self.open_entry(start)?;
if !entry.is_dir() {
return Err(io::Error::from(io::ErrorKind::NotFound));
return Err(Error::NotFound);
}
match dirname {
Some(name) => entry.to_dir().open_dir(name),

40
crates/bffs/src/entry.rs
View File

@@ -1,15 +1,15 @@
use core::{array::IntoIter, iter::Copied, str::Utf8Error};
use core::{char::DecodeUtf16, marker::PhantomData, slice::Iter};
use crate::io_ext::ReadLeExt;
use crate::{
Fat32FileSystem, ReadSeek,
consts::FATAttr,
dir::Dir,
error::Error,
file::{File, RawFile},
};
use io::Read;
use io::{IoBase, Read, ReadLeExt};
#[cfg(feature = "alloc")]
use alloc::borrow::ToOwned;
@@ -33,7 +33,7 @@ pub struct FatDirEntry {
}
impl FatDirEntry {
pub fn deserialize<T: Read>(reader: &mut T) -> Result<Self, io::Error> {
pub fn deserialize<T: Read>(reader: &mut T) -> Result<Self, T::Error> {
let mut name = [0u8; _];
reader.read_exact(&mut name)?;
let attr = reader.read_u8()?;
@@ -131,7 +131,7 @@ pub struct LongFileNameBuilder<T> {
_phantom: PhantomData<T>,
}
impl<T> LongFileNameBuilder<T> {
impl<T: IoBase> LongFileNameBuilder<T> {
pub fn new() -> Self {
Self {
inner: [0; _],
@@ -160,12 +160,12 @@ impl<T> LongFileNameBuilder<T> {
}
}
#[cfg(feature = "alloc")]
pub fn to_string(&self) -> Result<String, io::Error> {
pub fn to_string(&self) -> Result<String, Error<T::Error>> {
self.iter().try_collect::<String>()
}
}
impl<T> IntoIterator for LongFileNameBuilder<T> {
impl<T: IoBase> IntoIterator for LongFileNameBuilder<T> {
type Item = <LongFileNameIterator<T, IntoIter<u16, 256>> as Iterator>::Item;
type IntoIter = LongFileNameIterator<T, IntoIter<u16, 256>>;
@@ -178,7 +178,7 @@ impl<T> IntoIterator for LongFileNameBuilder<T> {
}
}
impl<T> LongFileNameBuilder<T> {
impl<T: IoBase> LongFileNameBuilder<T> {
pub fn iter(&self) -> LongFileNameIterator<T, Copied<Iter<'_, u16>>> {
LongFileNameIterator {
iterator: char::decode_utf16(self.inner.iter().copied()),
@@ -192,8 +192,8 @@ pub struct LongFileNameIterator<T, I: Iterator<Item = u16>> {
_phantom: PhantomData<T>,
}
impl<T, I: Iterator<Item = u16>> Iterator for LongFileNameIterator<T, I> {
type Item = Result<char, io::Error>;
impl<T: IoBase, I: Iterator<Item = u16>> Iterator for LongFileNameIterator<T, I> {
type Item = Result<char, Error<T::Error>>;
fn next(&mut self) -> Option<Self::Item> {
match self.iterator.next()? {
@@ -204,15 +204,12 @@ impl<T, I: Iterator<Item = u16>> Iterator for LongFileNameIterator<T, I> {
Some(Ok(value))
}
}
Err(_) => Some(Err(io::Error::new(
io::ErrorKind::Unsupported,
"Unsupported file name character",
))),
Err(_) => Some(Err(Error::UnsupportedFileNameCharacter)),
}
}
}
impl<T> Default for LongFileNameBuilder<T> {
impl<T: IoBase> Default for LongFileNameBuilder<T> {
fn default() -> Self {
Self::new()
}
@@ -229,7 +226,7 @@ impl<'a, T> DirectoryIterator<'a, T> {
}
impl<'a, T: ReadSeek + 'a> Iterator for DirectoryIterator<'a, T> {
type Item = Result<DirEntry<'a, T>, io::Error>;
type Item = Result<DirEntry<'a, T>, Error<T::Error>>;
fn next(&mut self) -> Option<Self::Item> {
let mut lfn_builder = LongFileNameBuilder::new();
@@ -286,7 +283,7 @@ pub struct DirEntry<'a, T> {
fs: &'a Fat32FileSystem<T>,
}
impl<'a, T> DirEntry<'a, T> {
impl<'a, T: IoBase> DirEntry<'a, T> {
fn new(
entry: FatDirEntry,
short_name: [u8; 11],
@@ -301,16 +298,13 @@ impl<'a, T> DirEntry<'a, T> {
}
}
#[cfg(feature = "alloc")]
pub fn name(&self) -> Result<String, io::Error> {
pub fn name(&self) -> Result<String, Error<T::Error>> {
if let Some(long_name) = self.long_name() {
long_name.to_string()
} else {
self.short_name().map(|n| n.to_owned()).map_err(|_| {
io::Error::new(
io::ErrorKind::Unsupported,
"Unsupported file name character",
)
})
self.short_name()
.map(|n| n.to_owned())
.map_err(|_| Error::UnsupportedFileNameCharacter)
}
}
pub fn long_name(&self) -> Option<&LongFileNameBuilder<T>> {

78
crates/bffs/src/error.rs
View File

@@ -1 +1,79 @@
use io::error::IoError;
/// Error enum with all errors that can be returned by functions from this crate
///
/// Generic parameter `T` is a type of external error returned by the user provided storage
#[derive(Debug)]
#[non_exhaustive]
pub enum Error<T> {
/// A user provided storage instance returned an error during an input/output operation.
Io(T),
/// A read operation cannot be completed because an end of a file has been reached prematurely.
UnexpectedEof,
/// A write operation cannot be completed because `Write::write` returned 0.
WriteZero,
/// A parameter was incorrect.
InvalidInput,
/// A requested file or directory has not been found.
NotFound,
/// A file or a directory with the same name already exists.
AlreadyExists,
/// An operation cannot be finished because a directory is not empty.
DirectoryIsNotEmpty,
/// File system internal structures are corrupted/invalid.
CorruptedFileSystem,
/// There is not enough free space on the storage to finish the requested operation.
NotEnoughSpace,
/// The provided file name is either too long or empty.
InvalidFileNameLength,
/// The provided file name contains an invalid character.
UnsupportedFileNameCharacter,
/// The file content contains invalid UTF-8 characters.
InvalidUTF8,
}
impl<T: IoError> From<T> for Error<T> {
fn from(error: T) -> Self {
Error::Io(error)
}
}
impl<T: core::fmt::Display> core::fmt::Display for Error<T> {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
match self {
Error::Io(io_error) => write!(f, "IO error: {}", io_error),
Error::UnexpectedEof => write!(f, "Unexpected end of file"),
Error::NotEnoughSpace => write!(f, "Not enough space"),
Error::WriteZero => write!(f, "Write zero"),
Error::InvalidInput => write!(f, "Invalid input"),
Error::InvalidFileNameLength => write!(f, "Invalid file name length"),
Error::UnsupportedFileNameCharacter => write!(f, "Unsupported file name character"),
Error::DirectoryIsNotEmpty => write!(f, "Directory is not empty"),
Error::NotFound => write!(f, "No such file or directory"),
Error::AlreadyExists => write!(f, "File or directory already exists"),
Error::CorruptedFileSystem => write!(f, "Corrupted file system"),
Error::InvalidUTF8 => write!(f, "File contains invalid UTF-8 characters"),
}
}
}
impl<T: core::fmt::Debug + IoError> IoError for Error<T> {
fn is_interrupted(&self) -> bool {
match self {
Error::<T>::Io(io_error) => io_error.is_interrupted(),
_ => false,
}
}
fn new_unexpected_eof_error() -> Self {
Error::<T>::UnexpectedEof
}
fn new_write_zero_error() -> Self {
Error::<T>::WriteZero
}
fn new_invalid_utf8_error() -> Self {
Error::<T>::InvalidUTF8
}
}

26
crates/bffs/src/file.rs
View File

@@ -1,9 +1,10 @@
use crate::{
Fat32FileSystem, ReadSeek, ReadWriteSeek,
consts::{FAT32_BAD_CLUSTER, FAT32_END_OF_CHAIN},
error::Error,
};
use io::{self, Read, Seek, Write};
use io::{self, IoBase, Read, Seek, Write};
#[derive(Debug, Clone)]
pub struct RawFile<'a, T> {
@@ -29,8 +30,12 @@ impl<'a, T> RawFile<'a, T> {
}
}
impl<'a, T: IoBase> IoBase for RawFile<'a, T> {
type Error = Error<T::Error>;
}
impl<'a, T: ReadSeek> Seek for RawFile<'a, T> {
fn seek(&mut self, pos: io::SeekFrom) -> Result<u64, io::Error> {
fn seek(&mut self, pos: io::SeekFrom) -> Result<u64, Self::Error> {
let new_pos = match pos {
io::SeekFrom::Start(s) => s,
io::SeekFrom::Current(c) => (self.pos as i64 + c) as u64,
@@ -62,7 +67,7 @@ impl<'a, T: ReadSeek> Seek for RawFile<'a, T> {
}
impl<'a, T: ReadSeek> Read for RawFile<'a, T> {
fn read(&mut self, buf: &mut [u8]) -> Result<usize, io::Error> {
fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error> {
let max_len = self
.size
.map(|size| core::cmp::min(buf.len(), size as usize - self.pos as usize))
@@ -111,11 +116,11 @@ impl<'a, T: ReadSeek> Read for RawFile<'a, T> {
}
}
impl<'a, T: ReadWriteSeek> Write for RawFile<'a, T> {
fn write(&mut self, _buf: &[u8]) -> Result<usize, io::Error> {
fn write(&mut self, _buf: &[u8]) -> Result<usize, Self::Error> {
todo!()
}
fn flush(&mut self) -> Result<(), io::Error> {
fn flush(&mut self) -> Result<(), Self::Error> {
todo!()
}
}
@@ -127,22 +132,25 @@ pub struct File<'a, T> {
fs: &'a Fat32FileSystem<T>,
}
impl<'a, T: IoBase> IoBase for File<'a, T> {
type Error = Error<T::Error>;
}
impl<'a, T: ReadSeek> Seek for File<'a, T> {
fn seek(&mut self, pos: io::SeekFrom) -> Result<u64, io::Error> {
fn seek(&mut self, pos: io::SeekFrom) -> Result<u64, Self::Error> {
self.raw.seek(pos)
}
}
impl<'a, T: ReadSeek> Read for File<'a, T> {
fn read(&mut self, buf: &mut [u8]) -> Result<usize, io::Error> {
fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error> {
self.raw.read(buf)
}
}
impl<'a, T: ReadWriteSeek> Write for File<'a, T> {
fn write(&mut self, buf: &[u8]) -> Result<usize, io::Error> {
fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
self.raw.write(buf)
}
fn flush(&mut self) -> Result<(), io::Error> {
fn flush(&mut self) -> Result<(), Self::Error> {
self.raw.flush()
}
}

27
crates/bffs/src/io_ext.rs
View File

@@ -1,27 +0,0 @@
use io::{Read, Result};
pub trait ReadLeExt {
fn read_u8(&mut self) -> Result<u8>;
fn read_u16_le(&mut self) -> Result<u16>;
fn read_u32_le(&mut self) -> Result<u32>;
}
impl<T: Read> ReadLeExt for T {
fn read_u8(&mut self) -> Result<u8> {
let mut buf = [0_u8; 1];
self.read_exact(&mut buf)?;
Ok(buf[0])
}
fn read_u16_le(&mut self) -> Result<u16> {
let mut buf = [0_u8; 2];
self.read_exact(&mut buf)?;
Ok(u16::from_le_bytes(buf))
}
fn read_u32_le(&mut self) -> Result<u32> {
let mut buf = [0_u8; 4];
self.read_exact(&mut buf)?;
Ok(u32::from_le_bytes(buf))
}
}

25
crates/bffs/src/lib.rs
View File

@@ -1,15 +1,20 @@
#![feature(iterator_try_collect, iter_order_by)]
#![allow(unused_features)]
#![cfg_attr(any(not(feature = "std"), target_arch = "riscv64"), no_std)]
use core::cell::RefCell;
use core::fmt::Display;
use crate::{
boot_sector::Fat32BootSector, consts::FAT32_CLUSTER_MASK, dir::Dir, entry::{DirEntry, FatEntry}, file::{File, RawFile}, io_ext::ReadLeExt, path::Path
boot_sector::Fat32BootSector,
consts::FAT32_CLUSTER_MASK,
dir::Dir,
entry::{DirEntry, FatEntry},
error::Error,
file::{File, RawFile},
path::Path,
};
use io::{Read, Seek, Write};
use io::{Read, ReadLeExt, Seek, Write};
#[cfg(feature = "alloc")]
extern crate alloc;
@@ -18,8 +23,8 @@ pub mod boot_sector;
pub mod consts;
pub mod dir;
pub mod entry;
pub mod error;
pub mod file;
pub mod io_ext;
pub mod path;
pub trait ReadSeek: Read + Seek {}
@@ -41,7 +46,7 @@ pub struct Fat32FsInfo {
}
impl Fat32FsInfo {
pub fn deserialize<T: Read>(disk: &mut T) -> Result<Self, io::Error> {
pub fn deserialize<T: Read>(disk: &mut T) -> Result<Self, Error<T::Error>> {
let lead_signature = disk.read_u32_le()?;
let mut reserved1 = [0u8; _];
disk.read_exact(&mut reserved1)?;
@@ -76,7 +81,7 @@ impl<T> Display for Fat32FileSystem<T> {
}
impl<T: ReadSeek> Fat32FileSystem<T> {
pub fn new(mut device: T) -> Result<Self, io::Error> {
pub fn new(mut device: T) -> Result<Self, Error<T::Error>> {
device.seek(io::SeekFrom::Start(0))?;
let boot_sector = Fat32BootSector::deserialize(&mut device)?;
@@ -86,7 +91,7 @@ impl<T: ReadSeek> Fat32FileSystem<T> {
})
}
/// Get the next cluster from the current one
fn get_next_cluster(&self, current_cluster: u32) -> Result<u32, io::Error> {
fn get_next_cluster(&self, current_cluster: u32) -> Result<u32, Error<T::Error>> {
let fat_offset =
self.fat_start_offset() + (current_cluster as u64 * size_of::<FatEntry>() as u64);
self.device
@@ -131,15 +136,15 @@ impl<T> Fat32FileSystem<T> {
}
}
impl<T: ReadSeek> Fat32FileSystem<T> {
pub fn open_entry<P: AsRef<Path>>(&self, path: P) -> Result<DirEntry<'_, T>, io::Error> {
pub fn open_entry<P: AsRef<Path>>(&self, path: P) -> Result<DirEntry<'_, T>, Error<T::Error>> {
let path = path.as_ref().as_str().trim_start_matches("/");
self.root_directory().open_entry(path)
}
pub fn open_dir<P: AsRef<Path>>(&self, path: P) -> Result<Dir<'_, T>, io::Error> {
pub fn open_dir<P: AsRef<Path>>(&self, path: P) -> Result<Dir<'_, T>, Error<T::Error>> {
let path = path.as_ref().as_str().trim_start_matches("/");
self.root_directory().open_dir(path)
}
pub fn open_file<P: AsRef<Path>>(&self, path: P) -> Result<File<'_, T>, io::Error> {
pub fn open_file<P: AsRef<Path>>(&self, path: P) -> Result<File<'_, T>, Error<T::Error>> {
let path = path.as_ref().as_str().trim_start_matches("/");
self.root_directory().open_file(path)
}

2
crates/bffs/src/main.rs
View File

@@ -9,7 +9,7 @@ pub fn main() {
// walk(fs.root_directory());
let mut f = fs.open_file("/usr/bin/agetty").unwrap();
let mut f = fs.open_file("/usr/bin/test_pic").unwrap();
let mut content = Vec::new();
f.read_to_end(&mut content).unwrap();
println!("file content len: {}", content.len());

7
crates/bffs/src/path.rs
View File

@@ -1,4 +1,3 @@
use core::fmt::Display;
#[cfg(feature = "alloc")]
use core::{borrow::Borrow, ops::Deref};
@@ -13,12 +12,6 @@ pub struct Path {
inner: str,
}
impl Display for Path {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
write!(f, "{}", &self.inner)
}
}
impl From<&str> for &Path {
fn from(value: &str) -> Self {
unsafe { &*(value as *const str as *const Path) }

3
crates/io/.gitignore vendored
View File

@@ -1,3 +0,0 @@
.cargo
target

5
crates/io/Cargo.toml
View File

@@ -1,9 +1,10 @@
[package]
name = "no-std-io"
name = "io"
version = "0.1.0"
edition = "2024"
[dependencies]
[features]
std = []
alloc = []
std = ["alloc"]

49
crates/io/justfile
View File

@@ -1,49 +0,0 @@
RUST_SRC := `rustc --print sysroot` / "lib/rustlib/src/rust/library/std/src"
copy-io:
#!/usr/bin/env bash
set -e
FILES=(
"io/error/repr_unpacked.rs"
"io/error/repr_bitpacked.rs"
"io/error.rs"
"io/buffered/mod.rs"
"io/buffered/linewriter.rs"
"io/buffered/linewritershim.rs"
"io/buffered/bufwriter.rs"
"io/buffered/bufreader.rs"
"io/buffered/bufreader/buffer.rs"
"io/copy.rs"
"io/cursor.rs"
"io/impls.rs"
"io/prelude.rs"
"io/util.rs"
"io/mod.rs"
)
for f in "${FILES[@]}"; do
echo "Processing $f..."
DEST="src/$f"
mkdir -p "$(dirname "$DEST")"
cp "{{ RUST_SRC }}/$f" "$DEST"
sed -i -E -n '$!N; /^#\[cfg\(test\)\]\nmod tests/d; P; D' "$DEST"
if [[ "$f" == "io/error.rs" ]]; then
sed -i "s/alloc::/alloc_crate::/g" "$DEST"
fi
if [[ "$f" == "io/mod.rs" ]]; then
sed -i "/mod pipe/d" "$DEST"
sed -i "/self::pipe/d" "$DEST"
sed -i "/mod stdio/d" "$DEST"
sed -i "/stdio::/d" "$DEST"
sed -i "/self::stdio/d" "$DEST"
sed -i "/feature = \"is_terminal\"/d" "$DEST"
sed -i "/feature = \"print_internals\"/d" "$DEST"
sed -i "/feature = \"internal_output_capture\"/d" "$DEST"
sed -i "/feature = \"anonymous_pipe\"/d" "$DEST"
fi
done

48
crates/io/src/error.rs Normal file
View File

@@ -0,0 +1,48 @@
/// Trait that should be implemented by errors returned from the user supplied storage.
///
/// Implementations for `std::io::Error` and `()` are provided by this crate.
pub trait IoError: core::fmt::Debug {
fn is_interrupted(&self) -> bool;
fn new_unexpected_eof_error() -> Self;
fn new_write_zero_error() -> Self;
fn new_invalid_utf8_error() -> Self;
}
impl IoError for () {
fn is_interrupted(&self) -> bool {
false
}
fn new_unexpected_eof_error() -> Self {
// empty
}
fn new_write_zero_error() -> Self {
// empty
}
fn new_invalid_utf8_error() -> Self {
// empty
}
}
#[cfg(all(feature = "std", not(target_arch = "riscv64")))]
impl IoError for std::io::Error {
fn is_interrupted(&self) -> bool {
self.kind() == std::io::ErrorKind::Interrupted
}
fn new_unexpected_eof_error() -> Self {
Self::new(
std::io::ErrorKind::UnexpectedEof,
"failed to fill whole buffer",
)
}
fn new_write_zero_error() -> Self {
Self::new(
std::io::ErrorKind::WriteZero,
"failed to write whole buffer",
)
}
}

357
crates/io/src/lib.rs
View File

@@ -1,70 +1,299 @@
#![cfg_attr(not(feature = "std"), no_std)]
#![cfg_attr(not(feature = "std"), stable(feature = "rust1", since = "1.0.0"))]
#![cfg_attr(
not(feature = "std"),
allow(
internal_features,
incomplete_features,
clippy::all,
dead_code,
unused_imports
)
)]
#![cfg_attr(
not(feature = "std"),
feature(
fmt_internals,
rustc_attrs,
decl_macro,
allow_internal_unstable,
staged_api,
core_io_borrowed_buf,
specialization,
prelude_import,
allocator_api,
slice_internals,
doc_notable_trait,
rustdoc_internals,
io_const_error,
maybe_uninit_array_assume_init,
try_with_capacity,
maybe_uninit_fill
)
)]
#![cfg_attr(any(not(feature = "std"), target_arch = "riscv64"), no_std)]
pub mod error;
#[cfg(not(feature = "std"))]
pub mod io;
#[cfg(not(feature = "std"))]
pub(crate) mod sys;
#[cfg(not(feature = "std"))]
#[stable(feature = "rust1", since = "1.0.0")]
pub use io::*;
use error::IoError;
#[cfg(not(feature = "std"))]
mod std_prelude {
pub(crate) use core::prelude::rust_2024::*;
#[cfg(feature = "alloc")]
extern crate alloc;
#[allow(unused_imports)]
pub(crate) use super::alloc_crate::{
boxed::Box,
string::{String, ToString},
vec,
vec::Vec,
};
#[cfg(feature = "alloc")]
use alloc::string::String;
#[cfg(feature = "alloc")]
use alloc::vec::Vec;
/// Provides IO error as an associated type.
///
/// Must be implemented for all types that also implement at least one of the following traits: `Read`, `Write`,
/// `Seek`.
pub trait IoBase {
/// Type of errors returned by input/output operations.
type Error: IoError;
}
#[cfg(not(feature = "std"))]
#[prelude_import]
#[allow(unused_imports)]
pub(crate) use std_prelude::*;
#[cfg(not(feature = "std"))]
extern crate alloc as alloc_crate;
#[cfg(not(feature = "std"))]
pub(crate) use alloc_crate::alloc;
#[cfg(not(feature = "std"))]
use alloc_crate::collections;
#[cfg(not(feature = "std"))]
use core::{cmp, error, fmt, hint, mem, ops, ptr, result, slice, str};
/// The `Read` trait allows for reading bytes from a source.
///
/// It is based on the `std::io::Read` trait.
pub trait Read: IoBase {
/// Pull some bytes from this source into the specified buffer, returning how many bytes were read.
///
/// This function does not provide any guarantees about whether it blocks waiting for data, but if an object needs
/// to block for a read and cannot, it will typically signal this via an Err return value.
///
/// If the return value of this method is `Ok(n)`, then it must be guaranteed that `0 <= n <= buf.len()`. A nonzero
/// `n` value indicates that the buffer buf has been filled in with n bytes of data from this source. If `n` is
/// `0`, then it can indicate one of two scenarios:
///
/// 1. This reader has reached its "end of file" and will likely no longer be able to produce bytes. Note that this
/// does not mean that the reader will always no longer be able to produce bytes.
/// 2. The buffer specified was 0 bytes in length.
///
/// It is not an error if the returned value `n` is smaller than the buffer size, even when the reader is not at
/// the end of the stream yet. This may happen for example because fewer bytes are actually available right now
/// (e. g. being close to end-of-file) or because `read()` was interrupted by a signal.
///
/// # Errors
///
/// If this function encounters any form of I/O or other error, an error will be returned. If an error is returned
/// then it must be guaranteed that no bytes were read.
/// An error for which `IoError::is_interrupted` returns true is non-fatal and the read operation should be retried
/// if there is nothing else to do.
fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error>;
#[cfg(feature = "std")]
pub use std::io::*;
/// Read the exact number of bytes required to fill `buf`.
///
/// This function reads as many bytes as necessary to completely fill the specified buffer `buf`.
///
/// # Errors
///
/// If this function encounters an error for which `IoError::is_interrupted` returns true then the error is ignored
/// and the operation will continue.
///
/// If this function encounters an end of file before completely filling the buffer, it returns an error
/// instantiated by a call to `IoError::new_unexpected_eof_error`. The contents of `buf` are unspecified in this
/// case.
///
/// If this function returns an error, it is unspecified how many bytes it has read, but it will never read more
/// than would be necessary to completely fill the buffer.
fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<(), Self::Error> {
while !buf.is_empty() {
match self.read(buf) {
Ok(0) => break,
Ok(n) => {
let tmp = buf;
buf = &mut tmp[n..];
}
Err(ref e) if e.is_interrupted() => {}
Err(e) => return Err(e),
}
}
if buf.is_empty() {
Ok(())
} else {
Err(Self::Error::new_unexpected_eof_error())
}
}
#[cfg(feature = "alloc")]
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Self::Error> {
const CHUNK_SIZE: usize = 32;
let start_len = buf.len();
loop {
let mut chunk_buf = [0; CHUNK_SIZE];
let read = self.read(&mut chunk_buf)?;
buf.extend_from_slice(&chunk_buf[..read]);
if read == 0 {
return Ok(buf.len() - start_len);
}
}
}
#[cfg(feature = "alloc")]
fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Self::Error> {
let read = self.read_to_end(unsafe { buf.as_mut_vec() })?;
if str::from_utf8(buf.as_bytes()).is_err() {
Err(Self::Error::new_invalid_utf8_error())
} else {
Ok(read)
}
}
}
/// The `Write` trait allows for writing bytes into the sink.
///
/// It is based on the `std::io::Write` trait.
pub trait Write: IoBase {
/// Write a buffer into this writer, returning how many bytes were written.
///
/// # Errors
///
/// Each call to write may generate an I/O error indicating that the operation could not be completed. If an error
/// is returned then no bytes in the buffer were written to this writer.
/// It is not considered an error if the entire buffer could not be written to this writer.
fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error>;
/// Attempts to write an entire buffer into this writer.
///
/// This method will continuously call `write` until there is no more data to be written or an error is returned.
/// Errors for which `IoError::is_interrupted` method returns true are being skipped. This method will not return
/// until the entire buffer has been successfully written or such an error occurs.
/// If `write` returns 0 before the entire buffer has been written this method will return an error instantiated by
/// a call to `IoError::new_write_zero_error`.
///
/// # Errors
///
/// This function will return the first error for which `IoError::is_interrupted` method returns false that `write`
/// returns.
fn write_all(&mut self, mut buf: &[u8]) -> Result<(), Self::Error> {
while !buf.is_empty() {
match self.write(buf) {
Ok(0) => {
return Err(Self::Error::new_write_zero_error());
}
Ok(n) => buf = &buf[n..],
Err(ref e) if e.is_interrupted() => {}
Err(e) => return Err(e),
}
}
Ok(())
}
/// Flush this output stream, ensuring that all intermediately buffered contents reach their destination.
///
/// # Errors
///
/// It is considered an error if not all bytes could be written due to I/O errors or EOF being reached.
fn flush(&mut self) -> Result<(), Self::Error>;
}
/// Enumeration of possible methods to seek within an I/O object.
///
/// It is based on the `std::io::SeekFrom` enum.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum SeekFrom {
/// Sets the offset to the provided number of bytes.
Start(u64),
/// Sets the offset to the size of this object plus the specified number of bytes.
End(i64),
/// Sets the offset to the current position plus the specified number of bytes.
Current(i64),
}
/// The `Seek` trait provides a cursor which can be moved within a stream of bytes.
///
/// It is based on the `std::io::Seek` trait.
pub trait Seek: IoBase {
/// Seek to an offset, in bytes, in a stream.
///
/// A seek beyond the end of a stream or to a negative position is not allowed.
///
/// If the seek operation completed successfully, this method returns the new position from the start of the
/// stream. That position can be used later with `SeekFrom::Start`.
///
/// # Errors
/// Seeking to a negative offset is considered an error.
fn seek(&mut self, pos: SeekFrom) -> Result<u64, Self::Error>;
}
#[cfg(all(feature = "std", not(target_arch = "riscv64")))]
impl From<SeekFrom> for std::io::SeekFrom {
fn from(from: SeekFrom) -> Self {
match from {
SeekFrom::Start(n) => std::io::SeekFrom::Start(n),
SeekFrom::End(n) => std::io::SeekFrom::End(n),
SeekFrom::Current(n) => std::io::SeekFrom::Current(n),
}
}
}
#[cfg(all(feature = "std", not(target_arch = "riscv64")))]
impl From<std::io::SeekFrom> for SeekFrom {
fn from(from: std::io::SeekFrom) -> Self {
match from {
std::io::SeekFrom::Start(n) => SeekFrom::Start(n),
std::io::SeekFrom::End(n) => SeekFrom::End(n),
std::io::SeekFrom::Current(n) => SeekFrom::Current(n),
}
}
}
#[cfg(all(feature = "std", not(target_arch = "riscv64")))]
impl IoBase for std::fs::File {
type Error = std::io::Error;
}
#[cfg(all(feature = "std", not(target_arch = "riscv64")))]
impl<T: std::io::Read + IoBase<Error = std::io::Error>> Read for T {
fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error> {
self.read(buf).map_err(Error::Io)
}
fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Self::Error> {
self.read_exact(buf).map_err(Error::Io)
}
}
#[cfg(all(feature = "std", not(target_arch = "riscv64")))]
impl<T: std::io::Write + IoBase<Error = std::io::Error>> Write for T {
fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
self.write(buf).map_err(Error::Io)
}
fn write_all(&mut self, buf: &[u8]) -> Result<(), Self::Error> {
self.write_all(buf).map_err(Error::Io)
}
fn flush(&mut self) -> Result<(), Self::Error> {
self.flush().map_err(Error::Io)
}
}
#[cfg(all(feature = "std", not(target_arch = "riscv64")))]
impl<T: std::io::Seek + IoBase<Error = std::io::Error>> Seek for T {
fn seek(&mut self, pos: SeekFrom) -> Result<u64, Self::Error> {
self.seek(pos.into()).map_err(Error::Io)
}
}
pub trait ReadLeExt {
type Error;
fn read_u8(&mut self) -> Result<u8, Self::Error>;
fn read_u16_le(&mut self) -> Result<u16, Self::Error>;
fn read_u32_le(&mut self) -> Result<u32, Self::Error>;
}
impl<T: Read> ReadLeExt for T {
type Error = <Self as IoBase>::Error;
fn read_u8(&mut self) -> Result<u8, Self::Error> {
let mut buf = [0_u8; 1];
self.read_exact(&mut buf)?;
Ok(buf[0])
}
fn read_u16_le(&mut self) -> Result<u16, Self::Error> {
let mut buf = [0_u8; 2];
self.read_exact(&mut buf)?;
Ok(u16::from_le_bytes(buf))
}
fn read_u32_le(&mut self) -> Result<u32, Self::Error> {
let mut buf = [0_u8; 4];
self.read_exact(&mut buf)?;
Ok(u32::from_le_bytes(buf))
}
}
#[allow(unused)]
pub(crate) trait WriteLeExt {
type Error;
fn write_u8(&mut self, n: u8) -> Result<(), Self::Error>;
fn write_u16_le(&mut self, n: u16) -> Result<(), Self::Error>;
fn write_u32_le(&mut self, n: u32) -> Result<(), Self::Error>;
}
impl<T: Write> WriteLeExt for T {
type Error = <Self as IoBase>::Error;
fn write_u8(&mut self, n: u8) -> Result<(), Self::Error> {
self.write_all(&[n])
}
fn write_u16_le(&mut self, n: u16) -> Result<(), Self::Error> {
self.write_all(&n.to_le_bytes())
}
fn write_u32_le(&mut self, n: u32) -> Result<(), Self::Error> {
self.write_all(&n.to_le_bytes())
}
}

1
crates/io/src/sys.rs
View File

@@ -1 +0,0 @@
pub(crate) mod io;

4
crates/io/src/sys/io/error/mod.rs
View File

@@ -1,4 +0,0 @@
mod generic;
pub use generic::*;
pub type RawOsError = i32;

26
crates/io/src/sys/io/mod.rs
View File

@@ -1,26 +0,0 @@
mod error;
mod io_slice {
mod unsupported;
pub use unsupported::*;
}
mod is_terminal {
mod unsupported;
pub use unsupported::*;
}
mod kernel_copy;
pub use error::{RawOsError, decode_error_kind, errno, error_string, is_interrupted};
pub use io_slice::{IoSlice, IoSliceMut};
pub use is_terminal::is_terminal;
pub use kernel_copy::{CopyState, kernel_copy};
// Bare metal platforms usually have very small amounts of RAM
// (in the order of hundreds of KB)
pub const DEFAULT_BUF_SIZE: usize = if cfg!(target_os = "espidf") {
512
} else {
8 * 1024
};

2
crates/kernel-macros/Cargo.toml
View File

@@ -7,6 +7,6 @@ edition = "2024"
proc-macro = true
[dependencies]
image = { version = "0.25", default-features = false, features = ["png"] }
image = "0.25"
syn = { version = "2", features = ["full"] }
zyn = "0.5"

12
crates/os-std-macros/Cargo.toml Normal file
View File

@@ -0,0 +1,12 @@
[package]
name = "os-std-macros"
version = "0.1.0"
edition = "2024"
[lib]
proc-macro = true
[dependencies]
proc-macro2 = "1"
quote = "1"
syn = { version = "2", features = ["full"] }

0
library/std/src/sys/fd/survos.rs → crates/os-std-macros/src/lib.rs
View File

2
crates/shared/Cargo.toml
View File

@@ -5,7 +5,7 @@ edition = "2024"
[dependencies]
bffs = { path = "../bffs" }
io = { package = "no-std-io", path = "../io" }
io = { path = "../io" }
[features]
kernel = []

12
crates/shared/src/fs.rs
View File

@@ -1,4 +1,4 @@
use io::{Read, Write};
use io::{IoBase, Read, Write};
use crate::syscall;
@@ -19,18 +19,22 @@ impl File {
}
}
impl IoBase for File {
type Error = ();
}
impl Read for File {
fn read(&mut self, buf: &mut [u8]) -> Result<usize, io::Error> {
fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error> {
Ok(syscall::read(self.as_fd(), buf) as usize)
}
}
impl Write for File {
fn write(&mut self, buf: &[u8]) -> Result<usize, io::Error> {
fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
Ok(syscall::write(self.as_fd(), buf) as usize)
}
fn flush(&mut self) -> Result<(), io::Error> {
fn flush(&mut self) -> Result<(), Self::Error> {
todo!()
}
}

80
crates/shared/src/syscall.rs
View File

@@ -1,5 +1,10 @@
use core::{alloc::Layout, time::Duration};
use bffs::path::Path;
use io::SeekFrom;
use crate::fs::File;
#[repr(u64)]
pub enum SysCall {
Read = 0,
@@ -13,7 +18,8 @@ pub enum SysCall {
ExecVE = 59,
Exit = 60,
NanoSleep = 101,
WaitPid = 247,
WriteIntTemp = 998,
WriteTemp = 999,
Unimplemented = 1 << 31,
}
@@ -31,7 +37,8 @@ impl From<u64> for SysCall {
59 => SysCall::ExecVE,
60 => SysCall::Exit,
101 => SysCall::NanoSleep,
247 => SysCall::WaitPid,
998 => SysCall::WriteIntTemp,
999 => SysCall::WriteTemp,
_ => SysCall::Unimplemented,
}
}
@@ -93,12 +100,10 @@ macro_rules! syscall {
};
}
pub fn exit() -> ! {
pub fn exit() {
unsafe {
syscall!(SysCall::Exit);
}
#[allow(clippy::empty_loop)]
loop {}
}
pub fn sleep(duration: Duration) {
@@ -108,8 +113,21 @@ pub fn sleep(duration: Duration) {
}
}
#[allow(unknown_lints)]
#[allow(fuzzy_provenance_casts)]
pub fn write_string_temp(content: &str) {
unsafe {
syscall!(
SysCall::WriteTemp,
content.as_ptr() as u64,
content.len() as u64
);
}
}
pub fn write_int_temp(content: u64) {
unsafe {
syscall!(SysCall::WriteIntTemp, content);
}
}
pub fn alloc(layout: Layout) -> *mut u8 {
unsafe {
let size = layout.size();
@@ -125,12 +143,13 @@ pub fn dealloc(ptr: *mut u8, layout: core::alloc::Layout) {
syscall!(SysCall::Dealloc, ptr as u64, size as u64, align as u64);
}
}
pub fn open(path: &str) -> u64 {
pub fn open<P: AsRef<Path>>(path: P) -> File {
unsafe {
let ptr = path.as_ptr();
let size = path.len();
let path_str = path.as_ref().as_str();
let ptr = path_str.as_ptr();
let size = path_str.len();
let (fd, ..) = syscall!(SysCall::Open, ptr as u64, size as u64);
fd
File::from_raw_fd(fd)
}
}
pub fn close(file_descriptor: u64) {
@@ -154,36 +173,29 @@ pub fn read(file_descriptor: u64, buf: &mut [u8]) -> u64 {
len
}
}
/// seek_type: 0 -> start, 1 -> end, 2 -> current
pub fn seek(file_descriptor: u64, seek_type: u8, seek: u64) {
pub fn seek(file_descriptor: u64, seek: SeekFrom) {
unsafe {
syscall!(SysCall::Seek, file_descriptor, seek_type as u64, seek);
let (discriminant, value) = match seek {
SeekFrom::Start(v) => (0, v),
SeekFrom::End(v) => (1, v as u64),
SeekFrom::Current(v) => (2, v as u64),
};
syscall!(SysCall::Seek, file_descriptor, discriminant, value);
}
}
pub fn spawn(path: &str, argc: isize, argv: *const *const u8) -> u64 {
pub fn spawn<P: AsRef<Path>>(path: P) {
unsafe {
let ptr = path.as_ptr();
let size = path.len();
let (pid, ..) = syscall!(
SysCall::Spawn,
ptr as u64,
size as u64,
argc as u64,
argv as u64
);
pid
let path_str = path.as_ref().as_str();
let ptr = path_str.as_ptr();
let size = path_str.len();
syscall!(SysCall::Spawn, ptr as u64, size as u64);
}
}
pub fn execve(path: &str) {
pub fn execve<P: AsRef<Path>>(path: P) {
unsafe {
let ptr = path.as_ptr();
let size = path.len();
let path_str = path.as_ref().as_str();
let ptr = path_str.as_ptr();
let size = path_str.len();
syscall!(SysCall::ExecVE, ptr as u64, size as u64);
}
}
pub fn waitpid(pid: usize) {
unsafe {
syscall!(SysCall::WaitPid, pid as u64);
}
}

10
crates/std/Cargo.toml Normal file
View File

@@ -0,0 +1,10 @@
[package]
name = "std"
version = "0.1.0"
edition = "2024"
[dependencies]
hashbrown = "0.16"
os-std-macros = { path = "../os-std-macros" }
shared = { path = "../shared", features = ["user"] }
io = { path = "../io", features = ["alloc"] }

490
crates/std/src/alloc.rs Normal file
View File

@@ -0,0 +1,490 @@
//! Memory allocation APIs.
//!
//! In a given program, the standard library has one “global” memory allocator
//! that is used for example by `Box<T>` and `Vec<T>`.
//!
//! Currently the default global allocator is unspecified. Libraries, however,
//! like `cdylib`s and `staticlib`s are guaranteed to use the [`System`] by
//! default.
//!
//! # The `#[global_allocator]` attribute
//!
//! This attribute allows configuring the choice of global allocator.
//! You can use this to implement a completely custom global allocator
//! to route all[^system-alloc] default allocation requests to a custom object.
//!
//! ```rust
//! use std::alloc::{GlobalAlloc, System, Layout};
//!
//! struct MyAllocator;
//!
//! unsafe impl GlobalAlloc for MyAllocator {
//! unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
//! unsafe { System.alloc(layout) }
//! }
//!
//! unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
//! unsafe { System.dealloc(ptr, layout) }
//! }
//! }
//!
//! #[global_allocator]
//! static GLOBAL: MyAllocator = MyAllocator;
//!
//! fn main() {
//! // This `Vec` will allocate memory through `GLOBAL` above
//! let mut v = Vec::new();
//! v.push(1);
//! }
//! ```
//!
//! The attribute is used on a `static` item whose type implements the
//! [`GlobalAlloc`] trait. This type can be provided by an external library:
//!
//! ```rust,ignore (demonstrates crates.io usage)
//! use jemallocator::Jemalloc;
//!
//! #[global_allocator]
//! static GLOBAL: Jemalloc = Jemalloc;
//!
//! fn main() {}
//! ```
//!
//! The `#[global_allocator]` can only be used once in a crate
//! or its recursive dependencies.
//!
//! [^system-alloc]: Note that the Rust standard library internals may still
//! directly call [`System`] when necessary (for example for the runtime
//! support typically required to implement a global allocator, see [re-entrance] on [`GlobalAlloc`]
//! for more details).
//!
//! [re-entrance]: trait.GlobalAlloc.html#re-entrance
#![deny(unsafe_op_in_unsafe_fn)]
#![stable(feature = "alloc_module", since = "1.28.0")]
use core::ptr::NonNull;
use core::sync::atomic::{AtomicBool, AtomicPtr, Ordering};
use core::{hint, mem, ptr};
#[stable(feature = "alloc_module", since = "1.28.0")]
#[doc(inline)]
pub use alloc_crate::alloc::*;
/// The default memory allocator provided by the operating system.
///
/// This is based on `malloc` on Unix platforms and `HeapAlloc` on Windows,
/// plus related functions. However, it is not valid to mix use of the backing
/// system allocator with `System`, as this implementation may include extra
/// work, such as to serve alignment requests greater than the alignment
/// provided directly by the backing system allocator.
///
/// This type implements the [`GlobalAlloc`] trait. Currently the default
/// global allocator is unspecified. Libraries, however, like `cdylib`s and
/// `staticlib`s are guaranteed to use the [`System`] by default and as such
/// work as if they had this definition:
///
/// ```rust
/// use std::alloc::System;
///
/// #[global_allocator]
/// static A: System = System;
///
/// fn main() {
/// let a = Box::new(4); // Allocates from the system allocator.
/// println!("{a}");
/// }
/// ```
///
/// You can also define your own wrapper around `System` if you'd like, such as
/// keeping track of the number of all bytes allocated:
///
/// ```rust
/// use std::alloc::{System, GlobalAlloc, Layout};
/// use std::sync::atomic::{AtomicUsize, Ordering::Relaxed};
///
/// struct Counter;
///
/// static ALLOCATED: AtomicUsize = AtomicUsize::new(0);
///
/// unsafe impl GlobalAlloc for Counter {
/// unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
/// let ret = unsafe { System.alloc(layout) };
/// if !ret.is_null() {
/// ALLOCATED.fetch_add(layout.size(), Relaxed);
/// }
/// ret
/// }
///
/// unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
/// unsafe { System.dealloc(ptr, layout); }
/// ALLOCATED.fetch_sub(layout.size(), Relaxed);
/// }
/// }
///
/// #[global_allocator]
/// static A: Counter = Counter;
///
/// fn main() {
/// println!("allocated bytes before main: {}", ALLOCATED.load(Relaxed));
/// }
/// ```
///
/// It can also be used directly to allocate memory independently of whatever
/// global allocator has been selected for a Rust program. For example if a Rust
/// program opts in to using jemalloc as the global allocator, `System` will
/// still allocate memory using `malloc` and `HeapAlloc`.
#[stable(feature = "alloc_system_type", since = "1.28.0")]
#[derive(Debug, Default, Copy, Clone)]
pub struct System;
impl System {
#[inline]
fn alloc_impl(&self, layout: Layout, zeroed: bool) -> Result<NonNull<[u8]>, AllocError> {
match layout.size() {
0 => Ok(NonNull::slice_from_raw_parts(layout.dangling_ptr(), 0)),
// SAFETY: `layout` is non-zero in size,
size => unsafe {
let raw_ptr = if zeroed {
GlobalAlloc::alloc_zeroed(self, layout)
} else {
GlobalAlloc::alloc(self, layout)
};
let ptr = NonNull::new(raw_ptr).ok_or(AllocError)?;
Ok(NonNull::slice_from_raw_parts(ptr, size))
},
}
}
// SAFETY: Same as `Allocator::grow`
#[inline]
unsafe fn grow_impl(
&self,
ptr: NonNull<u8>,
old_layout: Layout,
new_layout: Layout,
zeroed: bool,
) -> Result<NonNull<[u8]>, AllocError> {
debug_assert!(
new_layout.size() >= old_layout.size(),
"`new_layout.size()` must be greater than or equal to `old_layout.size()`"
);
match old_layout.size() {
0 => self.alloc_impl(new_layout, zeroed),
// SAFETY: `new_size` is non-zero as `new_size` is greater than or equal to `old_size`
// as required by safety conditions and the `old_size == 0` case was handled in the
// previous match arm. Other conditions must be upheld by the caller
old_size if old_layout.align() == new_layout.align() => unsafe {
let new_size = new_layout.size();
// `realloc` probably checks for `new_size >= old_layout.size()` or something similar.
hint::assert_unchecked(new_size >= old_layout.size());
let raw_ptr = GlobalAlloc::realloc(self, ptr.as_ptr(), old_layout, new_size);
let ptr = NonNull::new(raw_ptr).ok_or(AllocError)?;
if zeroed {
raw_ptr.add(old_size).write_bytes(0, new_size - old_size);
}
Ok(NonNull::slice_from_raw_parts(ptr, new_size))
},
// SAFETY: because `new_layout.size()` must be greater than or equal to `old_size`,
// both the old and new memory allocation are valid for reads and writes for `old_size`
// bytes. Also, because the old allocation wasn't yet deallocated, it cannot overlap
// `new_ptr`. Thus, the call to `copy_nonoverlapping` is safe. The safety contract
// for `dealloc` must be upheld by the caller.
old_size => unsafe {
let new_ptr = self.alloc_impl(new_layout, zeroed)?;
ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_mut_ptr(), old_size);
Allocator::deallocate(self, ptr, old_layout);
Ok(new_ptr)
},
}
}
}
// The Allocator impl checks the layout size to be non-zero and forwards to the GlobalAlloc impl,
// which is in `std::sys::*::alloc`.
#[unstable(feature = "allocator_api", issue = "32838")]
unsafe impl Allocator for System {
#[inline]
fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
self.alloc_impl(layout, false)
}
#[inline]
fn allocate_zeroed(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
self.alloc_impl(layout, true)
}
#[inline]
unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
if layout.size() != 0 {
// SAFETY: `layout` is non-zero in size,
// other conditions must be upheld by the caller
unsafe { GlobalAlloc::dealloc(self, ptr.as_ptr(), layout) }
}
}
#[inline]
unsafe fn grow(
&self,
ptr: NonNull<u8>,
old_layout: Layout,
new_layout: Layout,
) -> Result<NonNull<[u8]>, AllocError> {
// SAFETY: all conditions must be upheld by the caller
unsafe { self.grow_impl(ptr, old_layout, new_layout, false) }
}
#[inline]
unsafe fn grow_zeroed(
&self,
ptr: NonNull<u8>,
old_layout: Layout,
new_layout: Layout,
) -> Result<NonNull<[u8]>, AllocError> {
// SAFETY: all conditions must be upheld by the caller
unsafe { self.grow_impl(ptr, old_layout, new_layout, true) }
}
#[inline]
unsafe fn shrink(
&self,
ptr: NonNull<u8>,
old_layout: Layout,
new_layout: Layout,
) -> Result<NonNull<[u8]>, AllocError> {
debug_assert!(
new_layout.size() <= old_layout.size(),
"`new_layout.size()` must be smaller than or equal to `old_layout.size()`"
);
match new_layout.size() {
// SAFETY: conditions must be upheld by the caller
0 => unsafe {
Allocator::deallocate(self, ptr, old_layout);
Ok(NonNull::slice_from_raw_parts(new_layout.dangling_ptr(), 0))
},
// SAFETY: `new_size` is non-zero. Other conditions must be upheld by the caller
new_size if old_layout.align() == new_layout.align() => unsafe {
// `realloc` probably checks for `new_size <= old_layout.size()` or something similar.
hint::assert_unchecked(new_size <= old_layout.size());
let raw_ptr = GlobalAlloc::realloc(self, ptr.as_ptr(), old_layout, new_size);
let ptr = NonNull::new(raw_ptr).ok_or(AllocError)?;
Ok(NonNull::slice_from_raw_parts(ptr, new_size))
},
// SAFETY: because `new_size` must be smaller than or equal to `old_layout.size()`,
// both the old and new memory allocation are valid for reads and writes for `new_size`
// bytes. Also, because the old allocation wasn't yet deallocated, it cannot overlap
// `new_ptr`. Thus, the call to `copy_nonoverlapping` is safe. The safety contract
// for `dealloc` must be upheld by the caller.
new_size => unsafe {
let new_ptr = Allocator::allocate(self, new_layout)?;
ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_mut_ptr(), new_size);
Allocator::deallocate(self, ptr, old_layout);
Ok(new_ptr)
},
}
}
}
static HOOK: AtomicPtr<()> = AtomicPtr::new(ptr::null_mut());
/// Registers a custom allocation error hook, replacing any that was previously registered.
///
/// The allocation error hook is invoked when an infallible memory allocation fails — that is,
/// as a consequence of calling [`handle_alloc_error`] — before the runtime aborts.
///
/// The allocation error hook is a global resource. [`take_alloc_error_hook`] may be used to
/// retrieve a previously registered hook and wrap or discard it.
///
/// # What the provided `hook` function should expect
///
/// The hook function is provided with a [`Layout`] struct which contains information
/// about the allocation that failed.
///
/// The hook function may choose to panic or abort; in the event that it returns normally, this
/// will cause an immediate abort.
///
/// Since [`take_alloc_error_hook`] is a safe function that allows retrieving the hook, the hook
/// function must be _sound_ to call even if no memory allocations were attempted.
///
/// # The default hook
///
/// The default hook, used if [`set_alloc_error_hook`] is never called, prints a message to
/// standard error (and then returns, causing the runtime to abort the process).
/// Compiler options may cause it to panic instead, and the default behavior may be changed
/// to panicking in future versions of Rust.
///
/// # Examples
///
/// ```
/// #![feature(alloc_error_hook)]
///
/// use std::alloc::{Layout, set_alloc_error_hook};
///
/// fn custom_alloc_error_hook(layout: Layout) {
/// panic!("memory allocation of {} bytes failed", layout.size());
/// }
///
/// set_alloc_error_hook(custom_alloc_error_hook);
/// ```
#[unstable(feature = "alloc_error_hook", issue = "51245")]
pub fn set_alloc_error_hook(hook: fn(Layout)) {
HOOK.store(hook as *mut (), Ordering::Release);
}
// /// Unregisters the current allocation error hook, returning it.
// ///
// /// *See also the function [`set_alloc_error_hook`].*
// ///
// /// If no custom hook is registered, the default hook will be returned.
// #[unstable(feature = "alloc_error_hook", issue = "51245")]
// pub fn take_alloc_error_hook() -> fn(Layout) {
// let hook = HOOK.swap(ptr::null_mut(), Ordering::Acquire);
// if hook.is_null() { default_alloc_error_hook } else { unsafe { mem::transmute(hook) } }
// }
// #[optimize(size)]
// fn default_alloc_error_hook(layout: Layout) {
// if cfg!(panic = "immediate-abort") {
// return;
// }
// // This is the default path taken on OOM, and the only path taken on stable with std.
// // Crucially, it does *not* call any user-defined code, and therefore users do not have to
// // worry about allocation failure causing reentrancy issues. That makes it different from
// // the default `__rdl_alloc_error_handler` defined in alloc (i.e., the default alloc error
// // handler that is called when there is no `#[alloc_error_handler]`), which triggers a
// // regular panic and thus can invoke a user-defined panic hook, executing arbitrary
// // user-defined code.
// static PREV_ALLOC_FAILURE: AtomicBool = AtomicBool::new(false);
// if PREV_ALLOC_FAILURE.swap(true, Ordering::Relaxed) {
// // Don't try to print a backtrace if a previous alloc error happened. This likely means
// // there is not enough memory to print a backtrace, although it could also mean that two
// // threads concurrently run out of memory.
// rtprintpanic!(
// "memory allocation of {} bytes failed\nskipping backtrace printing to avoid potential recursion\n",
// layout.size()
// );
// return;
// } else {
// rtprintpanic!("memory allocation of {} bytes failed\n", layout.size());
// }
// let Some(mut out) = crate::sys::stdio::panic_output() else {
// return;
// };
// // Use a lock to prevent mixed output in multithreading context.
// // Some platforms also require it when printing a backtrace, like `SymFromAddr` on Windows.
// // Make sure to not take this lock until after checking PREV_ALLOC_FAILURE to avoid deadlocks
// // when there is too little memory to print a backtrace.
// let mut lock = crate::sys::backtrace::lock();
// match crate::panic::get_backtrace_style() {
// Some(crate::panic::BacktraceStyle::Short) => {
// drop(lock.print(&mut out, crate::backtrace_rs::PrintFmt::Short))
// }
// Some(crate::panic::BacktraceStyle::Full) => {
// drop(lock.print(&mut out, crate::backtrace_rs::PrintFmt::Full))
// }
// Some(crate::panic::BacktraceStyle::Off) => {
// use crate::io::Write;
// let _ = writeln!(
// out,
// "note: run with `RUST_BACKTRACE=1` environment variable to display a \
// backtrace"
// );
// if cfg!(miri) {
// let _ = writeln!(
// out,
// "note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` \
// for the environment variable to have an effect"
// );
// }
// }
// // If backtraces aren't supported or are forced-off, do nothing.
// None => {}
// }
// }
// #[cfg(not(test))]
// #[doc(hidden)]
// #[alloc_error_handler]
// #[unstable(feature = "alloc_internals", issue = "none")]
// pub fn rust_oom(layout: Layout) -> ! {
// crate::sys::backtrace::__rust_end_short_backtrace(|| {
// let hook = HOOK.load(Ordering::Acquire);
// let hook: fn(Layout) =
// if hook.is_null() { default_alloc_error_hook } else { unsafe { mem::transmute(hook) } };
// hook(layout);
// crate::process::abort()
// })
// }
#[cfg(not(test))]
#[doc(hidden)]
#[allow(unused_attributes)]
#[unstable(feature = "alloc_internals", issue = "none")]
pub mod __default_lib_allocator {
use super::{GlobalAlloc, Layout, System};
// These magic symbol names are used as a fallback for implementing the
// `__rust_alloc` etc symbols (see `src/liballoc/alloc.rs`) when there is
// no `#[global_allocator]` attribute.
// for symbol names src/librustc_ast/expand/allocator.rs
// for signatures src/librustc_allocator/lib.rs
// linkage directives are provided as part of the current compiler allocator
// ABI
#[rustc_std_internal_symbol]
pub unsafe extern "C" fn __rdl_alloc(size: usize, align: usize) -> *mut u8 {
// SAFETY: see the guarantees expected by `Layout::from_size_align` and
// `GlobalAlloc::alloc`.
unsafe {
let layout = Layout::from_size_align_unchecked(size, align);
System.alloc(layout)
}
}
#[rustc_std_internal_symbol]
pub unsafe extern "C" fn __rdl_dealloc(ptr: *mut u8, size: usize, align: usize) {
// SAFETY: see the guarantees expected by `Layout::from_size_align` and
// `GlobalAlloc::dealloc`.
unsafe { System.dealloc(ptr, Layout::from_size_align_unchecked(size, align)) }
}
#[rustc_std_internal_symbol]
pub unsafe extern "C" fn __rdl_realloc(
ptr: *mut u8,
old_size: usize,
align: usize,
new_size: usize,
) -> *mut u8 {
// SAFETY: see the guarantees expected by `Layout::from_size_align` and
// `GlobalAlloc::realloc`.
unsafe {
let old_layout = Layout::from_size_align_unchecked(old_size, align);
System.realloc(ptr, old_layout, new_size)
}
}
#[rustc_std_internal_symbol]
pub unsafe extern "C" fn __rdl_alloc_zeroed(size: usize, align: usize) -> *mut u8 {
// SAFETY: see the guarantees expected by `Layout::from_size_align` and
// `GlobalAlloc::alloc_zeroed`.
unsafe {
let layout = Layout::from_size_align_unchecked(size, align);
System.alloc_zeroed(layout)
}
}
}

4
crates/std/src/bstr.rs Normal file
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@@ -0,0 +1,4 @@
//! The `ByteStr` and `ByteString` types and trait implementations.
#[unstable(feature = "bstr", issue = "134915")]
pub use alloc_crate::bstr::{ByteStr, ByteString};

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4
crates/std/src/collections/hash/mod.rs Normal file
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@@ -0,0 +1,4 @@
//! Unordered containers, implemented as hash-tables
pub mod map;
pub mod set;

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6
crates/std/src/collections/mod.rs Normal file
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@@ -0,0 +1,6 @@
use core::marker::PhantomData;
pub struct HashMap<K, V, T> {
_phantom: PhantomData<(K, V, T)>,
}
pub use alloc_crate::collections;

5
crates/std/src/env.rs Normal file
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@@ -0,0 +1,5 @@
use crate::ffi::OsString;
pub fn var_os(s: &str) -> Option<OsString> {
None
}

4
crates/std/src/error.rs Normal file
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@@ -0,0 +1,4 @@
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::error::Error;
#[unstable(feature = "error_generic_member_access", issue = "99301")]
pub use core::error::{Request, request_ref, request_value};

14
crates/std/src/ffi/c_str.rs Normal file
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@@ -0,0 +1,14 @@
//! [`CStr`], [`CString`], and related types.
#[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")]
pub use alloc_crate::ffi::c_str::FromVecWithNulError;
#[stable(feature = "cstring_into", since = "1.7.0")]
pub use alloc_crate::ffi::c_str::IntoStringError;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::ffi::c_str::{CString, NulError};
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::ffi::c_str::CStr;
#[stable(feature = "cstr_from_bytes_until_nul", since = "1.69.0")]
pub use core::ffi::c_str::FromBytesUntilNulError;
#[stable(feature = "cstr_from_bytes", since = "1.10.0")]
pub use core::ffi::c_str::FromBytesWithNulError;

207
crates/std/src/ffi/mod.rs Normal file
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@@ -0,0 +1,207 @@
//! Utilities related to FFI bindings.
//!
//! This module provides utilities to handle data across non-Rust
//! interfaces, like other programming languages and the underlying
//! operating system. It is mainly of use for FFI (Foreign Function
//! Interface) bindings and code that needs to exchange C-like strings
//! with other languages.
//!
//! # Overview
//!
//! Rust represents owned strings with the [`String`] type, and
//! borrowed slices of strings with the [`str`] primitive. Both are
//! always in UTF-8 encoding, and may contain nul bytes in the middle,
//! i.e., if you look at the bytes that make up the string, there may
//! be a `\0` among them. Both `String` and `str` store their length
//! explicitly; there are no nul terminators at the end of strings
//! like in C.
//!
//! C strings are different from Rust strings:
//!
//! * **Encodings** - Rust strings are UTF-8, but C strings may use
//! other encodings. If you are using a string from C, you should
//! check its encoding explicitly, rather than just assuming that it
//! is UTF-8 like you can do in Rust.
//!
//! * **Character size** - C strings may use `char` or `wchar_t`-sized
//! characters; please **note** that C's `char` is different from Rust's.
//! The C standard leaves the actual sizes of those types open to
//! interpretation, but defines different APIs for strings made up of
//! each character type. Rust strings are always UTF-8, so different
//! Unicode characters will be encoded in a variable number of bytes
//! each. The Rust type [`char`] represents a '[Unicode scalar
//! value]', which is similar to, but not the same as, a '[Unicode
//! code point]'.
//!
//! * **Nul terminators and implicit string lengths** - Often, C
//! strings are nul-terminated, i.e., they have a `\0` character at the
//! end. The length of a string buffer is not stored, but has to be
//! calculated; to compute the length of a string, C code must
//! manually call a function like `strlen()` for `char`-based strings,
//! or `wcslen()` for `wchar_t`-based ones. Those functions return
//! the number of characters in the string excluding the nul
//! terminator, so the buffer length is really `len+1` characters.
//! Rust strings don't have a nul terminator; their length is always
//! stored and does not need to be calculated. While in Rust
//! accessing a string's length is an *O*(1) operation (because the
//! length is stored); in C it is an *O*(*n*) operation because the
//! length needs to be computed by scanning the string for the nul
//! terminator.
//!
//! * **Internal nul characters** - When C strings have a nul
//! terminator character, this usually means that they cannot have nul
//! characters in the middle — a nul character would essentially
//! truncate the string. Rust strings *can* have nul characters in
//! the middle, because nul does not have to mark the end of the
//! string in Rust.
//!
//! # Representations of non-Rust strings
//!
//! [`CString`] and [`CStr`] are useful when you need to transfer
//! UTF-8 strings to and from languages with a C ABI, like Python.
//!
//! * **From Rust to C:** [`CString`] represents an owned, C-friendly
//! string: it is nul-terminated, and has no internal nul characters.
//! Rust code can create a [`CString`] out of a normal string (provided
//! that the string doesn't have nul characters in the middle), and
//! then use a variety of methods to obtain a raw <code>\*mut [u8]</code> that can
//! then be passed as an argument to functions which use the C
//! conventions for strings.
//!
//! * **From C to Rust:** [`CStr`] represents a borrowed C string; it
//! is what you would use to wrap a raw <code>\*const [u8]</code> that you got from
//! a C function. A [`CStr`] is guaranteed to be a nul-terminated array
//! of bytes. Once you have a [`CStr`], you can convert it to a Rust
//! <code>&[str]</code> if it's valid UTF-8, or lossily convert it by adding
//! replacement characters.
//!
//! [`OsString`] and [`OsStr`] are useful when you need to transfer
//! strings to and from the operating system itself, or when capturing
//! the output of external commands. Conversions between [`OsString`],
//! [`OsStr`] and Rust strings work similarly to those for [`CString`]
//! and [`CStr`].
//!
//! * [`OsString`] losslessly represents an owned platform string. However, this
//! representation is not necessarily in a form native to the platform.
//! In the Rust standard library, various APIs that transfer strings to/from the operating
//! system use [`OsString`] instead of plain strings. For example,
//! [`env::var_os()`] is used to query environment variables; it
//! returns an <code>[Option]<[OsString]></code>. If the environment variable
//! exists you will get a <code>[Some]\(os_string)</code>, which you can
//! *then* try to convert to a Rust string. This yields a [`Result`], so that
//! your code can detect errors in case the environment variable did
//! not in fact contain valid Unicode data.
//!
//! * [`OsStr`] losslessly represents a borrowed reference to a platform string.
//! However, this representation is not necessarily in a form native to the platform.
//! It can be converted into a UTF-8 Rust string slice in a similar way to
//! [`OsString`].
//!
//! # Conversions
//!
//! ## On Unix
//!
//! On Unix, [`OsStr`] implements the
//! <code>std::os::unix::ffi::[OsStrExt][unix.OsStrExt]</code> trait, which
//! augments it with two methods, [`from_bytes`] and [`as_bytes`].
//! These do inexpensive conversions from and to byte slices.
//!
//! Additionally, on Unix [`OsString`] implements the
//! <code>std::os::unix::ffi::[OsStringExt][unix.OsStringExt]</code> trait,
//! which provides [`from_vec`] and [`into_vec`] methods that consume
//! their arguments, and take or produce vectors of [`u8`].
//!
//! ## On Windows
//!
//! An [`OsStr`] can be losslessly converted to a native Windows string. And
//! a native Windows string can be losslessly converted to an [`OsString`].
//!
//! On Windows, [`OsStr`] implements the
//! <code>std::os::windows::ffi::[OsStrExt][windows.OsStrExt]</code> trait,
//! which provides an [`encode_wide`] method. This provides an
//! iterator that can be [`collect`]ed into a vector of [`u16`]. After a nul
//! characters is appended, this is the same as a native Windows string.
//!
//! Additionally, on Windows [`OsString`] implements the
//! <code>std::os::windows:ffi::[OsStringExt][windows.OsStringExt]</code>
//! trait, which provides a [`from_wide`] method to convert a native Windows
//! string (without the terminating nul character) to an [`OsString`].
//!
//! ## Other platforms
//!
//! Many other platforms provide their own extension traits in a
//! `std::os::*::ffi` module.
//!
//! ## On all platforms
//!
//! On all platforms, [`OsStr`] consists of a sequence of bytes that is encoded as a superset of
//! UTF-8; see [`OsString`] for more details on its encoding on different platforms.
//!
//! For limited, inexpensive conversions from and to bytes, see [`OsStr::as_encoded_bytes`] and
//! [`OsStr::from_encoded_bytes_unchecked`].
//!
//! For basic string processing, see [`OsStr::slice_encoded_bytes`].
//!
//! [Unicode scalar value]: https://www.unicode.org/glossary/#unicode_scalar_value
//! [Unicode code point]: https://www.unicode.org/glossary/#code_point
//! [`env::set_var()`]: crate::env::set_var "env::set_var"
//! [`env::var_os()`]: crate::env::var_os "env::var_os"
//! [unix.OsStringExt]: crate::os::unix::ffi::OsStringExt "os::unix::ffi::OsStringExt"
//! [`from_vec`]: crate::os::unix::ffi::OsStringExt::from_vec "os::unix::ffi::OsStringExt::from_vec"
//! [`into_vec`]: crate::os::unix::ffi::OsStringExt::into_vec "os::unix::ffi::OsStringExt::into_vec"
//! [unix.OsStrExt]: crate::os::unix::ffi::OsStrExt "os::unix::ffi::OsStrExt"
//! [`from_bytes`]: crate::os::unix::ffi::OsStrExt::from_bytes "os::unix::ffi::OsStrExt::from_bytes"
//! [`as_bytes`]: crate::os::unix::ffi::OsStrExt::as_bytes "os::unix::ffi::OsStrExt::as_bytes"
//! [`OsStrExt`]: crate::os::unix::ffi::OsStrExt "os::unix::ffi::OsStrExt"
//! [windows.OsStrExt]: crate::os::windows::ffi::OsStrExt "os::windows::ffi::OsStrExt"
//! [`encode_wide`]: crate::os::windows::ffi::OsStrExt::encode_wide "os::windows::ffi::OsStrExt::encode_wide"
//! [`collect`]: crate::iter::Iterator::collect "iter::Iterator::collect"
//! [windows.OsStringExt]: crate::os::windows::ffi::OsStringExt "os::windows::ffi::OsStringExt"
//! [`from_wide`]: crate::os::windows::ffi::OsStringExt::from_wide "os::windows::ffi::OsStringExt::from_wide"
#![stable(feature = "rust1", since = "1.0.0")]
#[stable(feature = "c_str_module", since = "1.88.0")]
pub mod c_str;
#[stable(feature = "core_c_void", since = "1.30.0")]
pub use core::ffi::c_void;
#[unstable(
feature = "c_variadic",
reason = "the `c_variadic` feature has not been properly tested on \
all supported platforms",
issue = "44930"
)]
pub use core::ffi::{VaArgSafe, VaList};
#[stable(feature = "core_ffi_c", since = "1.64.0")]
pub use core::ffi::{
c_char, c_double, c_float, c_int, c_long, c_longlong, c_schar, c_short, c_uchar, c_uint,
c_ulong, c_ulonglong, c_ushort,
};
#[unstable(feature = "c_size_t", issue = "88345")]
pub use core::ffi::{c_ptrdiff_t, c_size_t, c_ssize_t};
#[doc(inline)]
#[stable(feature = "cstr_from_bytes_until_nul", since = "1.69.0")]
pub use self::c_str::FromBytesUntilNulError;
#[doc(inline)]
#[stable(feature = "cstr_from_bytes", since = "1.10.0")]
pub use self::c_str::FromBytesWithNulError;
#[doc(inline)]
#[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")]
pub use self::c_str::FromVecWithNulError;
#[doc(inline)]
#[stable(feature = "cstring_into", since = "1.7.0")]
pub use self::c_str::IntoStringError;
#[doc(inline)]
#[stable(feature = "rust1", since = "1.0.0")]
pub use self::c_str::NulError;
#[doc(inline)]
#[stable(feature = "rust1", since = "1.0.0")]
pub use self::c_str::{CStr, CString};
#[stable(feature = "rust1", since = "1.0.0")]
#[doc(inline)]
pub use self::os_str::{OsStr, OsString};
#[stable(feature = "os_str_display", since = "1.87.0")]
pub mod os_str;

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use super::*;
use crate::mem::MaybeUninit;
use crate::ptr;
#[test]
fn test_os_string_with_capacity() {
let os_string = OsString::with_capacity(0);
assert_eq!(0, os_string.inner.into_inner().capacity());
let os_string = OsString::with_capacity(10);
assert_eq!(10, os_string.inner.into_inner().capacity());
let mut os_string = OsString::with_capacity(0);
os_string.push("abc");
assert!(os_string.inner.into_inner().capacity() >= 3);
}
#[test]
fn test_os_string_clear() {
let mut os_string = OsString::from("abc");
assert_eq!(3, os_string.inner.as_inner().len());
os_string.clear();
assert_eq!(&os_string, "");
assert_eq!(0, os_string.inner.as_inner().len());
}
#[test]
fn test_os_string_leak() {
let os_string = OsString::from("have a cake");
let (len, cap) = (os_string.len(), os_string.capacity());
let leaked = os_string.leak();
assert_eq!(leaked.as_encoded_bytes(), b"have a cake");
unsafe { drop(String::from_raw_parts(leaked as *mut OsStr as _, len, cap)) }
}
#[test]
fn test_os_string_capacity() {
let os_string = OsString::with_capacity(0);
assert_eq!(0, os_string.capacity());
let os_string = OsString::with_capacity(10);
assert_eq!(10, os_string.capacity());
let mut os_string = OsString::with_capacity(0);
os_string.push("abc");
assert!(os_string.capacity() >= 3);
}
#[test]
fn test_os_string_reserve() {
let mut os_string = OsString::new();
assert_eq!(os_string.capacity(), 0);
os_string.reserve(2);
assert!(os_string.capacity() >= 2);
for _ in 0..16 {
os_string.push("a");
}
assert!(os_string.capacity() >= 16);
os_string.reserve(16);
assert!(os_string.capacity() >= 32);
os_string.push("a");
os_string.reserve(16);
assert!(os_string.capacity() >= 33)
}
#[test]
fn test_os_string_reserve_exact() {
let mut os_string = OsString::new();
assert_eq!(os_string.capacity(), 0);
os_string.reserve_exact(2);
assert!(os_string.capacity() >= 2);
for _ in 0..16 {
os_string.push("a");
}
assert!(os_string.capacity() >= 16);
os_string.reserve_exact(16);
assert!(os_string.capacity() >= 32);
os_string.push("a");
os_string.reserve_exact(16);
assert!(os_string.capacity() >= 33)
}
#[test]
fn test_os_string_join() {
let strings = [OsStr::new("hello"), OsStr::new("dear"), OsStr::new("world")];
assert_eq!("hello", strings[..1].join(OsStr::new(" ")));
assert_eq!("hello dear world", strings.join(OsStr::new(" ")));
assert_eq!("hellodearworld", strings.join(OsStr::new("")));
assert_eq!("hello.\n dear.\n world", strings.join(OsStr::new(".\n ")));
assert_eq!("dear world", strings[1..].join(&OsString::from(" ")));
let strings_abc = [OsString::from("a"), OsString::from("b"), OsString::from("c")];
assert_eq!("a b c", strings_abc.join(OsStr::new(" ")));
}
#[test]
fn test_os_string_default() {
let os_string: OsString = Default::default();
assert_eq!("", &os_string);
}
#[test]
fn test_os_str_is_empty() {
let mut os_string = OsString::new();
assert!(os_string.is_empty());
os_string.push("abc");
assert!(!os_string.is_empty());
os_string.clear();
assert!(os_string.is_empty());
}
#[test]
fn test_os_str_len() {
let mut os_string = OsString::new();
assert_eq!(0, os_string.len());
os_string.push("abc");
assert_eq!(3, os_string.len());
os_string.clear();
assert_eq!(0, os_string.len());
}
#[test]
fn test_os_str_default() {
let os_str: &OsStr = Default::default();
assert_eq!("", os_str);
}
#[test]
fn into_boxed() {
let orig = "Hello, world!";
let os_str = OsStr::new(orig);
let boxed: Box<OsStr> = Box::from(os_str);
let os_string = os_str.to_owned().into_boxed_os_str().into_os_string();
assert_eq!(os_str, &*boxed);
assert_eq!(&*boxed, &*os_string);
assert_eq!(&*os_string, os_str);
}
#[test]
fn boxed_default() {
let boxed = <Box<OsStr>>::default();
assert!(boxed.is_empty());
}
#[test]
fn test_os_str_clone_into() {
let mut os_string = OsString::with_capacity(123);
os_string.push("hello");
let os_str = OsStr::new("bonjour");
os_str.clone_into(&mut os_string);
assert_eq!(os_str, os_string);
assert!(os_string.capacity() >= 123);
}
#[test]
fn into_rc() {
let orig = "Hello, world!";
let os_str = OsStr::new(orig);
let rc: Rc<OsStr> = Rc::from(os_str);
let arc: Arc<OsStr> = Arc::from(os_str);
assert_eq!(&*rc, os_str);
assert_eq!(&*arc, os_str);
let rc2: Rc<OsStr> = Rc::from(os_str.to_owned());
let arc2: Arc<OsStr> = Arc::from(os_str.to_owned());
assert_eq!(&*rc2, os_str);
assert_eq!(&*arc2, os_str);
}
#[test]
fn slice_encoded_bytes() {
let os_str = OsStr::new("123θგ🦀");
// ASCII
let digits = os_str.slice_encoded_bytes(..3);
assert_eq!(digits, "123");
let three = os_str.slice_encoded_bytes(2..3);
assert_eq!(three, "3");
// 2-byte UTF-8
let theta = os_str.slice_encoded_bytes(3..5);
assert_eq!(theta, "θ");
// 3-byte UTF-8
let gani = os_str.slice_encoded_bytes(5..8);
assert_eq!(gani, "გ");
// 4-byte UTF-8
let crab = os_str.slice_encoded_bytes(8..);
assert_eq!(crab, "🦀");
}
#[test]
#[should_panic]
fn slice_out_of_bounds() {
let crab = OsStr::new("🦀");
let _ = crab.slice_encoded_bytes(..5);
}
#[test]
#[should_panic]
fn slice_mid_char() {
let crab = OsStr::new("🦀");
let _ = crab.slice_encoded_bytes(..2);
}
#[cfg(unix)]
#[test]
#[should_panic(expected = "byte index 1 is not an OsStr boundary")]
fn slice_invalid_data() {
use crate::os::unix::ffi::OsStrExt;
let os_string = OsStr::from_bytes(b"\xFF\xFF");
let _ = os_string.slice_encoded_bytes(1..);
}
#[cfg(unix)]
#[test]
#[should_panic(expected = "byte index 1 is not an OsStr boundary")]
fn slice_partial_utf8() {
use crate::os::unix::ffi::{OsStrExt, OsStringExt};
let part_crab = OsStr::from_bytes(&"🦀".as_bytes()[..3]);
let mut os_string = OsString::from_vec(vec![0xFF]);
os_string.push(part_crab);
let _ = os_string.slice_encoded_bytes(1..);
}
#[cfg(unix)]
#[test]
fn slice_invalid_edge() {
use crate::os::unix::ffi::{OsStrExt, OsStringExt};
let os_string = OsStr::from_bytes(b"a\xFFa");
assert_eq!(os_string.slice_encoded_bytes(..1), "a");
assert_eq!(os_string.slice_encoded_bytes(1..), OsStr::from_bytes(b"\xFFa"));
assert_eq!(os_string.slice_encoded_bytes(..2), OsStr::from_bytes(b"a\xFF"));
assert_eq!(os_string.slice_encoded_bytes(2..), "a");
let os_string = OsStr::from_bytes(&"abc🦀".as_bytes()[..6]);
assert_eq!(os_string.slice_encoded_bytes(..3), "abc");
assert_eq!(os_string.slice_encoded_bytes(3..), OsStr::from_bytes(b"\xF0\x9F\xA6"));
let mut os_string = OsString::from_vec(vec![0xFF]);
os_string.push("🦀");
assert_eq!(os_string.slice_encoded_bytes(..1), OsStr::from_bytes(b"\xFF"));
assert_eq!(os_string.slice_encoded_bytes(1..), "🦀");
}
#[cfg(windows)]
#[test]
#[should_panic(expected = "byte index 3 lies between surrogate codepoints")]
fn slice_between_surrogates() {
use crate::os::windows::ffi::OsStringExt;
let os_string = OsString::from_wide(&[0xD800, 0xD800]);
assert_eq!(os_string.as_encoded_bytes(), &[0xED, 0xA0, 0x80, 0xED, 0xA0, 0x80]);
let _ = os_string.slice_encoded_bytes(..3);
}
#[cfg(windows)]
#[test]
fn slice_surrogate_edge() {
use crate::os::windows::ffi::OsStringExt;
let surrogate = OsString::from_wide(&[0xD800]);
let mut pre_crab = surrogate.clone();
pre_crab.push("🦀");
assert_eq!(pre_crab.slice_encoded_bytes(..3), surrogate);
assert_eq!(pre_crab.slice_encoded_bytes(3..), "🦀");
let mut post_crab = OsString::from("🦀");
post_crab.push(&surrogate);
assert_eq!(post_crab.slice_encoded_bytes(..4), "🦀");
assert_eq!(post_crab.slice_encoded_bytes(4..), surrogate);
}
#[test]
fn clone_to_uninit() {
let a = OsStr::new("hello.txt");
let mut storage = vec![MaybeUninit::<u8>::uninit(); size_of_val::<OsStr>(a)];
unsafe { a.clone_to_uninit(ptr::from_mut::<[_]>(storage.as_mut_slice()).cast()) };
assert_eq!(a.as_encoded_bytes(), unsafe { storage.assume_init_ref() });
let mut b: Box<OsStr> = OsStr::new("world.exe").into();
assert_eq!(size_of_val::<OsStr>(a), size_of_val::<OsStr>(&b));
assert_ne!(a, &*b);
unsafe { a.clone_to_uninit(ptr::from_mut::<OsStr>(&mut b).cast()) };
assert_eq!(a, &*b);
}
#[test]
fn debug() {
let s = "'single quotes'";
assert_eq!(format!("{:?}", OsStr::new(s)), format!("{:?}", s));
}

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//! Generic hashing support.
//!
//! This module provides a generic way to compute the [hash] of a value.
//! Hashes are most commonly used with [`HashMap`] and [`HashSet`].
//!
//! [hash]: https://en.wikipedia.org/wiki/Hash_function
//! [`HashMap`]: ../../std/collections/struct.HashMap.html
//! [`HashSet`]: ../../std/collections/struct.HashSet.html
//!
//! The simplest way to make a type hashable is to use `#[derive(Hash)]`:
//!
//! # Examples
//!
//! ```rust
//! use std::hash::{DefaultHasher, Hash, Hasher};
//!
//! #[derive(Hash)]
//! struct Person {
//! id: u32,
//! name: String,
//! phone: u64,
//! }
//!
//! let person1 = Person {
//! id: 5,
//! name: "Janet".to_string(),
//! phone: 555_666_7777,
//! };
//! let person2 = Person {
//! id: 5,
//! name: "Bob".to_string(),
//! phone: 555_666_7777,
//! };
//!
//! assert!(calculate_hash(&person1) != calculate_hash(&person2));
//!
//! fn calculate_hash<T: Hash>(t: &T) -> u64 {
//! let mut s = DefaultHasher::new();
//! t.hash(&mut s);
//! s.finish()
//! }
//! ```
//!
//! If you need more control over how a value is hashed, you need to implement
//! the [`Hash`] trait:
//!
//! ```rust
//! use std::hash::{DefaultHasher, Hash, Hasher};
//!
//! struct Person {
//! id: u32,
//! # #[allow(dead_code)]
//! name: String,
//! phone: u64,
//! }
//!
//! impl Hash for Person {
//! fn hash<H: Hasher>(&self, state: &mut H) {
//! self.id.hash(state);
//! self.phone.hash(state);
//! }
//! }
//!
//! let person1 = Person {
//! id: 5,
//! name: "Janet".to_string(),
//! phone: 555_666_7777,
//! };
//! let person2 = Person {
//! id: 5,
//! name: "Bob".to_string(),
//! phone: 555_666_7777,
//! };
//!
//! assert_eq!(calculate_hash(&person1), calculate_hash(&person2));
//!
//! fn calculate_hash<T: Hash>(t: &T) -> u64 {
//! let mut s = DefaultHasher::new();
//! t.hash(&mut s);
//! s.finish()
//! }
//! ```
#![stable(feature = "rust1", since = "1.0.0")]
pub(crate) mod random;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::hash::*;
#[stable(feature = "std_hash_exports", since = "1.76.0")]
pub use self::random::{DefaultHasher, RandomState};

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//! This module exists to isolate [`RandomState`] and [`DefaultHasher`] outside of the
//! [`collections`] module without actually publicly exporting them, so that parts of that
//! implementation can more easily be moved to the [`alloc`] crate.
//!
//! Although its items are public and contain stability attributes, they can't actually be accessed
//! outside this crate.
//!
//! [`collections`]: crate::collections
use super::{BuildHasher, Hasher, SipHasher13};
use crate::cell::Cell;
use crate::fmt;
use crate::sys::random::hashmap_random_keys;
/// `RandomState` is the default state for [`HashMap`] types.
///
/// A particular instance `RandomState` will create the same instances of
/// [`Hasher`], but the hashers created by two different `RandomState`
/// instances are unlikely to produce the same result for the same values.
///
/// [`HashMap`]: crate::collections::HashMap
///
/// # Examples
///
/// ```
/// use std::collections::HashMap;
/// use std::hash::RandomState;
///
/// let s = RandomState::new();
/// let mut map = HashMap::with_hasher(s);
/// map.insert(1, 2);
/// ```
#[stable(feature = "hashmap_build_hasher", since = "1.7.0")]
#[derive(Clone)]
pub struct RandomState {
k0: u64,
k1: u64,
}
impl RandomState {
/// Constructs a new `RandomState` that is initialized with random keys.
///
/// # Examples
///
/// ```
/// use std::hash::RandomState;
///
/// let s = RandomState::new();
/// ```
#[inline]
#[allow(deprecated)]
// rand
#[must_use]
#[stable(feature = "hashmap_build_hasher", since = "1.7.0")]
pub fn new() -> RandomState {
// Historically this function did not cache keys from the OS and instead
// simply always called `rand::thread_rng().gen()` twice. In #31356 it
// was discovered, however, that because we re-seed the thread-local RNG
// from the OS periodically that this can cause excessive slowdown when
// many hash maps are created on a thread. To solve this performance
// trap we cache the first set of randomly generated keys per-thread.
//
// Later in #36481 it was discovered that exposing a deterministic
// iteration order allows a form of DOS attack. To counter that we
// increment one of the seeds on every RandomState creation, giving
// every corresponding HashMap a different iteration order.
thread_local!(static KEYS: Cell<(u64, u64)> = {
Cell::new(hashmap_random_keys())
});
KEYS.with(|keys| {
let (k0, k1) = keys.get();
keys.set((k0.wrapping_add(1), k1));
RandomState { k0, k1 }
})
}
}
#[stable(feature = "hashmap_build_hasher", since = "1.7.0")]
impl BuildHasher for RandomState {
type Hasher = DefaultHasher;
#[inline]
fn build_hasher(&self) -> DefaultHasher {
DefaultHasher(SipHasher13::new_with_keys(self.k0, self.k1))
}
}
/// The default [`Hasher`] used by [`RandomState`].
///
/// The internal algorithm is not specified, and so it and its hashes should
/// not be relied upon over releases.
#[derive(Clone, Debug)]
#[stable(feature = "hashmap_build_hasher", since = "1.7.0")]
pub struct DefaultHasher(SipHasher13);
impl DefaultHasher {
/// Creates a new `DefaultHasher`.
///
/// This hasher is not guaranteed to be the same as all other
/// `DefaultHasher` instances, but is the same as all other `DefaultHasher`
/// instances created through `new` or `default`.
#[stable(feature = "hashmap_default_hasher", since = "1.13.0")]
#[inline]
#[rustc_const_unstable(feature = "const_default", issue = "143894")]
#[must_use]
pub const fn new() -> DefaultHasher {
DefaultHasher(SipHasher13::new_with_keys(0, 0))
}
}
#[stable(feature = "hashmap_default_hasher", since = "1.13.0")]
#[rustc_const_unstable(feature = "const_default", issue = "143894")]
impl const Default for DefaultHasher {
/// Creates a new `DefaultHasher` using [`new`].
/// See its documentation for more.
///
/// [`new`]: DefaultHasher::new
#[inline]
fn default() -> DefaultHasher {
DefaultHasher::new()
}
}
#[stable(feature = "hashmap_default_hasher", since = "1.13.0")]
impl Hasher for DefaultHasher {
// The underlying `SipHasher13` doesn't override the other
// `write_*` methods, so it's ok not to forward them here.
#[inline]
fn write(&mut self, msg: &[u8]) {
self.0.write(msg)
}
#[inline]
fn write_str(&mut self, s: &str) {
self.0.write_str(s);
}
#[inline]
fn finish(&self) -> u64 {
self.0.finish()
}
}
#[stable(feature = "hashmap_build_hasher", since = "1.7.0")]
impl Default for RandomState {
/// Constructs a new `RandomState`.
#[inline]
fn default() -> RandomState {
RandomState::new()
}
}
#[stable(feature = "std_debug", since = "1.16.0")]
impl fmt::Debug for RandomState {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("RandomState").finish_non_exhaustive()
}
}

600
crates/io/src/io/mod.rs → crates/std/src/io.rs
View File

@@ -1,338 +1,54 @@
//! Traits, helpers, and type definitions for core I/O functionality.
//!
//! The `std::io` module contains a number of common things you'll need
//! when doing input and output. The most core part of this module is
//! the [`Read`] and [`Write`] traits, which provide the
//! most general interface for reading and writing input and output.
//!
//! ## Read and Write
//!
//! Because they are traits, [`Read`] and [`Write`] are implemented by a number
//! of other types, and you can implement them for your types too. As such,
//! you'll see a few different types of I/O throughout the documentation in
//! this module: [`File`]s, [`TcpStream`]s, and sometimes even [`Vec<T>`]s. For
//! example, [`Read`] adds a [`read`][`Read::read`] method, which we can use on
//! [`File`]s:
//!
//! ```no_run
//! use std::io;
//! use std::io::prelude::*;
//! use std::fs::File;
//!
//! fn main() -> io::Result<()> {
//! let mut f = File::open("foo.txt")?;
//! let mut buffer = [0; 10];
//!
//! // read up to 10 bytes
//! let n = f.read(&mut buffer)?;
//!
//! println!("The bytes: {:?}", &buffer[..n]);
//! Ok(())
//! }
//! ```
//!
//! [`Read`] and [`Write`] are so important, implementors of the two traits have a
//! nickname: readers and writers. So you'll sometimes see 'a reader' instead
//! of 'a type that implements the [`Read`] trait'. Much easier!
//!
//! ## Seek and BufRead
//!
//! Beyond that, there are two important traits that are provided: [`Seek`]
//! and [`BufRead`]. Both of these build on top of a reader to control
//! how the reading happens. [`Seek`] lets you control where the next byte is
//! coming from:
//!
//! ```no_run
//! use std::io;
//! use std::io::prelude::*;
//! use std::io::SeekFrom;
//! use std::fs::File;
//!
//! fn main() -> io::Result<()> {
//! let mut f = File::open("foo.txt")?;
//! let mut buffer = [0; 10];
//!
//! // skip to the last 10 bytes of the file
//! f.seek(SeekFrom::End(-10))?;
//!
//! // read up to 10 bytes
//! let n = f.read(&mut buffer)?;
//!
//! println!("The bytes: {:?}", &buffer[..n]);
//! Ok(())
//! }
//! ```
//!
//! [`BufRead`] uses an internal buffer to provide a number of other ways to read, but
//! to show it off, we'll need to talk about buffers in general. Keep reading!
//!
//! ## BufReader and BufWriter
//!
//! Byte-based interfaces are unwieldy and can be inefficient, as we'd need to be
//! making near-constant calls to the operating system. To help with this,
//! `std::io` comes with two structs, [`BufReader`] and [`BufWriter`], which wrap
//! readers and writers. The wrapper uses a buffer, reducing the number of
//! calls and providing nicer methods for accessing exactly what you want.
//!
//! For example, [`BufReader`] works with the [`BufRead`] trait to add extra
//! methods to any reader:
//!
//! ```no_run
//! use std::io;
//! use std::io::prelude::*;
//! use std::io::BufReader;
//! use std::fs::File;
//!
//! fn main() -> io::Result<()> {
//! let f = File::open("foo.txt")?;
//! let mut reader = BufReader::new(f);
//! let mut buffer = String::new();
//!
//! // read a line into buffer
//! reader.read_line(&mut buffer)?;
//!
//! println!("{buffer}");
//! Ok(())
//! }
//! ```
//!
//! [`BufWriter`] doesn't add any new ways of writing; it just buffers every call
//! to [`write`][`Write::write`]:
//!
//! ```no_run
//! use std::io;
//! use std::io::prelude::*;
//! use std::io::BufWriter;
//! use std::fs::File;
//!
//! fn main() -> io::Result<()> {
//! let f = File::create("foo.txt")?;
//! {
//! let mut writer = BufWriter::new(f);
//!
//! // write a byte to the buffer
//! writer.write(&[42])?;
//!
//! } // the buffer is flushed once writer goes out of scope
//!
//! Ok(())
//! }
//! ```
//!
//! ## Standard input and output
//!
//! A very common source of input is standard input:
//!
//! ```no_run
//! use std::io;
//!
//! fn main() -> io::Result<()> {
//! let mut input = String::new();
//!
//! io::stdin().read_line(&mut input)?;
//!
//! println!("You typed: {}", input.trim());
//! Ok(())
//! }
//! ```
//!
//! Note that you cannot use the [`?` operator] in functions that do not return
//! a [`Result<T, E>`][`Result`]. Instead, you can call [`.unwrap()`]
//! or `match` on the return value to catch any possible errors:
//!
//! ```no_run
//! use std::io;
//!
//! let mut input = String::new();
//!
//! io::stdin().read_line(&mut input).unwrap();
//! ```
//!
//! And a very common source of output is standard output:
//!
//! ```no_run
//! use std::io;
//! use std::io::prelude::*;
//!
//! fn main() -> io::Result<()> {
//! io::stdout().write(&[42])?;
//! Ok(())
//! }
//! ```
//!
//! Of course, using [`io::stdout`] directly is less common than something like
//! [`println!`].
//!
//! ## Iterator types
//!
//! A large number of the structures provided by `std::io` are for various
//! ways of iterating over I/O. For example, [`Lines`] is used to split over
//! lines:
//!
//! ```no_run
//! use std::io;
//! use std::io::prelude::*;
//! use std::io::BufReader;
//! use std::fs::File;
//!
//! fn main() -> io::Result<()> {
//! let f = File::open("foo.txt")?;
//! let reader = BufReader::new(f);
//!
//! for line in reader.lines() {
//! println!("{}", line?);
//! }
//! Ok(())
//! }
//! ```
//!
//! ## Functions
//!
//! There are a number of [functions][functions-list] that offer access to various
//! features. For example, we can use three of these functions to copy everything
//! from standard input to standard output:
//!
//! ```no_run
//! use std::io;
//!
//! fn main() -> io::Result<()> {
//! io::copy(&mut io::stdin(), &mut io::stdout())?;
//! Ok(())
//! }
//! ```
//!
//! [functions-list]: #functions-1
//!
//! ## io::Result
//!
//! Last, but certainly not least, is [`io::Result`]. This type is used
//! as the return type of many `std::io` functions that can cause an error, and
//! can be returned from your own functions as well. Many of the examples in this
//! module use the [`?` operator]:
//!
//! ```
//! use std::io;
//!
//! fn read_input() -> io::Result<()> {
//! let mut input = String::new();
//!
//! io::stdin().read_line(&mut input)?;
//!
//! println!("You typed: {}", input.trim());
//!
//! Ok(())
//! }
//! ```
//!
//! The return type of `read_input()`, [`io::Result<()>`][`io::Result`], is a very
//! common type for functions which don't have a 'real' return value, but do want to
//! return errors if they happen. In this case, the only purpose of this function is
//! to read the line and print it, so we use `()`.
//!
//! ## Platform-specific behavior
//!
//! Many I/O functions throughout the standard library are documented to indicate
//! what various library or syscalls they are delegated to. This is done to help
//! applications both understand what's happening under the hood as well as investigate
//! any possibly unclear semantics. Note, however, that this is informative, not a binding
//! contract. The implementation of many of these functions are subject to change over
//! time and may call fewer or more syscalls/library functions.
//!
//! ## I/O Safety
//!
//! Rust follows an I/O safety discipline that is comparable to its memory safety discipline. This
//! means that file descriptors can be *exclusively owned*. (Here, "file descriptor" is meant to
//! subsume similar concepts that exist across a wide range of operating systems even if they might
//! use a different name, such as "handle".) An exclusively owned file descriptor is one that no
//! other code is allowed to access in any way, but the owner is allowed to access and even close
//! it any time. A type that owns its file descriptor should usually close it in its `drop`
//! function. Types like [`File`] own their file descriptor. Similarly, file descriptors
//! can be *borrowed*, granting the temporary right to perform operations on this file descriptor.
//! This indicates that the file descriptor will not be closed for the lifetime of the borrow, but
//! it does *not* imply any right to close this file descriptor, since it will likely be owned by
//! someone else.
//!
//! The platform-specific parts of the Rust standard library expose types that reflect these
//! concepts, see [`os::unix`] and [`os::windows`].
//!
//! To uphold I/O safety, it is crucial that no code acts on file descriptors it does not own or
//! borrow, and no code closes file descriptors it does not own. In other words, a safe function
//! that takes a regular integer, treats it as a file descriptor, and acts on it, is *unsound*.
//!
//! Not upholding I/O safety and acting on a file descriptor without proof of ownership can lead to
//! misbehavior and even Undefined Behavior in code that relies on ownership of its file
//! descriptors: a closed file descriptor could be re-allocated, so the original owner of that file
//! descriptor is now working on the wrong file. Some code might even rely on fully encapsulating
//! its file descriptors with no operations being performed by any other part of the program.
//!
//! Note that exclusive ownership of a file descriptor does *not* imply exclusive ownership of the
//! underlying kernel object that the file descriptor references (also called "open file description" on
//! some operating systems). File descriptors basically work like [`Arc`]: when you receive an owned
//! file descriptor, you cannot know whether there are any other file descriptors that reference the
//! same kernel object. However, when you create a new kernel object, you know that you are holding
//! the only reference to it. Just be careful not to lend it to anyone, since they can obtain a
//! clone and then you can no longer know what the reference count is! In that sense, [`OwnedFd`] is
//! like `Arc` and [`BorrowedFd<'a>`] is like `&'a Arc` (and similar for the Windows types). In
//! particular, given a `BorrowedFd<'a>`, you are not allowed to close the file descriptor -- just
//! like how, given a `&'a Arc`, you are not allowed to decrement the reference count and
//! potentially free the underlying object. There is no equivalent to `Box` for file descriptors in
//! the standard library (that would be a type that guarantees that the reference count is `1`),
//! however, it would be possible for a crate to define a type with those semantics.
//!
//! [`File`]: crate::fs::File
//! [`TcpStream`]: crate::net::TcpStream
//! [`io::stdout`]: stdout
//! [`io::Result`]: self::Result
//! [`?` operator]: ../../book/appendix-02-operators.html
//! [`Result`]: crate::result::Result
//! [`.unwrap()`]: crate::result::Result::unwrap
//! [`os::unix`]: ../os/unix/io/index.html
//! [`os::windows`]: ../os/windows/io/index.html
//! [`OwnedFd`]: ../os/fd/struct.OwnedFd.html
//! [`BorrowedFd<'a>`]: ../os/fd/struct.BorrowedFd.html
//! [`Arc`]: crate::sync::Arc
#[cfg(test)]
mod tests;
#![stable(feature = "rust1", since = "1.0.0")]
pub mod error;
pub use self::buffered::{BufReader, BufWriter, IntoInnerError, LineWriter};
pub use self::error::{Error, ErrorKind, Result, SimpleMessage, const_error};
pub mod buffered;
pub mod copy;
pub mod cursor;
pub mod impls;
pub mod pipe;
pub mod stdio;
pub mod prelude;
pub mod util;
#[unstable(feature = "read_buf", issue = "78485")]
pub use core::io::{BorrowedBuf, BorrowedCursor};
use core::slice::memchr;
#[stable(feature = "bufwriter_into_parts", since = "1.56.0")]
pub use self::buffered::WriterPanicked;
#[unstable(feature = "raw_os_error_ty", issue = "107792")]
pub use self::error::RawOsError;
#[doc(hidden)]
#[unstable(feature = "io_const_error_internals", issue = "none")]
pub use self::error::SimpleMessage;
#[unstable(feature = "io_const_error", issue = "133448")]
pub use self::error::const_error;
#[doc(hidden)]
#[doc(no_inline, hidden)]
#[stable(feature = "rust1", since = "1.0.0")]
pub use self::{
buffered::{BufReader, BufWriter, IntoInnerError, LineWriter},
copy::copy,
cursor::Cursor,
error::{Error, ErrorKind, Result},
util::{Empty, Repeat, Sink, empty, repeat, sink},
};
use crate::mem::{MaybeUninit, take};
use crate::ops::{Deref, DerefMut};
use crate::{cmp, fmt, slice, str, sys};
#[unstable(feature = "read_buf", issue = "78485")]
pub use core::io::{BorrowedBuf, BorrowedCursor};
pub use cursor::Cursor;
use core::slice::memchr;
pub use stdio::try_set_output_capture;
mod buffered;
pub(crate) mod copy;
mod cursor;
mod error;
mod impls;
pub mod prelude;
mod util;
use crate::fs::File;
use io::IoBase;
// pub use io::Read;
// pub use io::Seek;
// pub use io::SeekFrom;
// pub use io::Write;
pub struct Stdin;
impl IoBase for Stdin {
type Error = ();
}
impl io::Read for Stdin {
fn read(&mut self, buf: &mut [u8]) -> core::result::Result<usize, Self::Error> {
unsafe { File::from_raw_fd(0).read(buf) }
}
}
pub fn stdin() -> Stdin {
Stdin
}
// Part took from the real std
const DEFAULT_BUF_SIZE: usize = crate::sys::io::DEFAULT_BUF_SIZE;
struct Guard<'a> {
buf: &'a mut Vec<u8>,
len: usize,
@@ -346,30 +62,14 @@ impl Drop for Guard<'_> {
}
}
// Several `read_to_string` and `read_line` methods in the standard library will
// append data into a `String` buffer, but we need to be pretty careful when
// doing this. The implementation will just call `.as_mut_vec()` and then
// delegate to a byte-oriented reading method, but we must ensure that when
// returning we never leave `buf` in a state such that it contains invalid UTF-8
// in its bounds.
//
// To this end, we use an RAII guard (to protect against panics) which updates
// the length of the string when it is dropped. This guard initially truncates
// the string to the prior length and only after we've validated that the
// new contents are valid UTF-8 do we allow it to set a longer length.
//
// The unsafety in this function is twofold:
//
// 1. We're looking at the raw bytes of `buf`, so we take on the burden of UTF-8
// checks.
// 2. We're passing a raw buffer to the function `f`, and it is expected that
// the function only *appends* bytes to the buffer. We'll get undefined
// behavior if existing bytes are overwritten to have non-UTF-8 data.
pub(crate) unsafe fn append_to_string<F>(buf: &mut String, f: F) -> Result<usize>
where
F: FnOnce(&mut Vec<u8>) -> Result<usize>,
{
let mut g = Guard { len: buf.len(), buf: unsafe { buf.as_mut_vec() } };
let mut g = Guard {
len: buf.len(),
buf: unsafe { buf.as_mut_vec() },
};
let ret = f(g.buf);
// SAFETY: the caller promises to only append data to `buf`
@@ -401,7 +101,10 @@ pub(crate) fn default_read_to_end<R: Read + ?Sized>(
// Optionally limit the maximum bytes read on each iteration.
// This adds an arbitrary fiddle factor to allow for more data than we expect.
let mut max_read_size = size_hint
.and_then(|s| s.checked_add(1024)?.checked_next_multiple_of(DEFAULT_BUF_SIZE))
.and_then(|s| {
s.checked_add(1024)?
.checked_next_multiple_of(DEFAULT_BUF_SIZE)
})
.unwrap_or(DEFAULT_BUF_SIZE);
let mut initialized = 0; // Extra initialized bytes from previous loop iteration
@@ -542,7 +245,10 @@ pub(crate) fn default_read_vectored<F>(read: F, bufs: &mut [IoSliceMut<'_>]) ->
where
F: FnOnce(&mut [u8]) -> Result<usize>,
{
let buf = bufs.iter_mut().find(|b| !b.is_empty()).map_or(&mut [][..], |b| &mut **b);
let buf = bufs
.iter_mut()
.find(|b| !b.is_empty())
.map_or(&mut [][..], |b| &mut **b);
read(buf)
}
@@ -550,7 +256,10 @@ pub(crate) fn default_write_vectored<F>(write: F, bufs: &[IoSlice<'_>]) -> Resul
where
F: FnOnce(&[u8]) -> Result<usize>,
{
let buf = bufs.iter().find(|b| !b.is_empty()).map_or(&[][..], |b| &**b);
let buf = bufs
.iter()
.find(|b| !b.is_empty())
.map_or(&[][..], |b| &**b);
write(buf)
}
@@ -565,7 +274,11 @@ pub(crate) fn default_read_exact<R: Read + ?Sized>(this: &mut R, mut buf: &mut [
Err(e) => return Err(e),
}
}
if !buf.is_empty() { Err(Error::READ_EXACT_EOF) } else { Ok(()) }
if !buf.is_empty() {
Err(Error::READ_EXACT_EOF)
} else {
Ok(())
}
}
pub(crate) fn default_read_buf<F>(read: F, mut cursor: BorrowedCursor<'_>) -> Result<()>
@@ -620,7 +333,10 @@ pub(crate) fn default_write_fmt<W: Write + ?Sized>(
}
}
let mut output = Adapter { inner: this, error: Ok(()) };
let mut output = Adapter {
inner: this,
error: Ok(()),
};
match fmt::write(&mut output, args) {
Ok(()) => Ok(()),
Err(..) => {
@@ -638,79 +354,6 @@ pub(crate) fn default_write_fmt<W: Write + ?Sized>(
}
}
/// The `Read` trait allows for reading bytes from a source.
///
/// Implementors of the `Read` trait are called 'readers'.
///
/// Readers are defined by one required method, [`read()`]. Each call to [`read()`]
/// will attempt to pull bytes from this source into a provided buffer. A
/// number of other methods are implemented in terms of [`read()`], giving
/// implementors a number of ways to read bytes while only needing to implement
/// a single method.
///
/// Readers are intended to be composable with one another. Many implementors
/// throughout [`std::io`] take and provide types which implement the `Read`
/// trait.
///
/// Please note that each call to [`read()`] may involve a system call, and
/// therefore, using something that implements [`BufRead`], such as
/// [`BufReader`], will be more efficient.
///
/// Repeated calls to the reader use the same cursor, so for example
/// calling `read_to_end` twice on a [`File`] will only return the file's
/// contents once. It's recommended to first call `rewind()` in that case.
///
/// # Examples
///
/// [`File`]s implement `Read`:
///
/// ```no_run
/// use std::io;
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// fn main() -> io::Result<()> {
/// let mut f = File::open("foo.txt")?;
/// let mut buffer = [0; 10];
///
/// // read up to 10 bytes
/// f.read(&mut buffer)?;
///
/// let mut buffer = Vec::new();
/// // read the whole file
/// f.read_to_end(&mut buffer)?;
///
/// // read into a String, so that you don't need to do the conversion.
/// let mut buffer = String::new();
/// f.read_to_string(&mut buffer)?;
///
/// // and more! See the other methods for more details.
/// Ok(())
/// }
/// ```
///
/// Read from [`&str`] because [`&[u8]`][prim@slice] implements `Read`:
///
/// ```no_run
/// # use std::io;
/// use std::io::prelude::*;
///
/// fn main() -> io::Result<()> {
/// let mut b = "This string will be read".as_bytes();
/// let mut buffer = [0; 10];
///
/// // read up to 10 bytes
/// b.read(&mut buffer)?;
///
/// // etc... it works exactly as a File does!
/// Ok(())
/// }
/// ```
///
/// [`read()`]: Read::read
/// [`&str`]: prim@str
/// [`std::io`]: self
/// [`File`]: crate::fs::File
#[stable(feature = "rust1", since = "1.0.0")]
#[doc(notable_trait)]
#[cfg_attr(not(test), rustc_diagnostic_item = "IoRead")]
@@ -808,7 +451,8 @@ pub trait Read {
/// buffer provided, or an empty one if none exists.
#[stable(feature = "iovec", since = "1.36.0")]
fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize> {
default_read_vectored(|b| self.read(b), bufs)
// default_read_vectored(|b| self.read(b), bufs)
todo!()
}
/// Determines if this `Read`er has an efficient `read_vectored`
@@ -918,7 +562,8 @@ pub trait Read {
/// [`Vec::try_reserve`]: crate::vec::Vec::try_reserve
#[stable(feature = "rust1", since = "1.0.0")]
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
default_read_to_end(self, buf, None)
// default_read_to_end(self, buf, None)
todo!()
}
/// Reads all bytes until EOF in this source, appending them to `buf`.
@@ -974,7 +619,8 @@ pub trait Read {
/// [`std::fs::read_to_string`]: crate::fs::read_to_string
#[stable(feature = "rust1", since = "1.0.0")]
fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
default_read_to_string(self, buf, None)
// default_read_to_string(self, buf, None)
todo!()
}
/// Reads the exact number of bytes required to fill `buf`.
@@ -1027,7 +673,8 @@ pub trait Read {
/// ```
#[stable(feature = "read_exact", since = "1.6.0")]
fn read_exact(&mut self, buf: &mut [u8]) -> Result<()> {
default_read_exact(self, buf)
// default_read_exact(self, buf)
todo!()
}
/// Pull some bytes from this source into the specified buffer.
@@ -1040,7 +687,8 @@ pub trait Read {
/// This method makes it possible to return both data and an error but it is advised against.
#[unstable(feature = "read_buf", issue = "78485")]
fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<()> {
default_read_buf(|b| self.read(b), buf)
// default_read_buf(|b| self.read(b), buf)
todo!()
}
/// Reads the exact number of bytes required to fill `cursor`.
@@ -1063,7 +711,8 @@ pub trait Read {
/// If this function returns an error, all bytes read will be appended to `cursor`.
#[unstable(feature = "read_buf", issue = "78485")]
fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<()> {
default_read_buf_exact(self, cursor)
// default_read_buf_exact(self, cursor)
todo!()
}
/// Creates a "by reference" adapter for this instance of `Read`.
@@ -1186,7 +835,11 @@ pub trait Read {
where
Self: Sized,
{
Chain { first: self, second: next, done_first: false }
Chain {
first: self,
second: next,
done_first: false,
}
}
/// Creates an adapter which will read at most `limit` bytes from it.
@@ -1225,7 +878,11 @@ pub trait Read {
where
Self: Sized,
{
Take { inner: self, len: limit, limit }
Take {
inner: self,
len: limit,
limit,
}
}
/// Read and return a fixed array of bytes from this source.
@@ -2279,55 +1936,6 @@ fn skip_until<R: BufRead + ?Sized>(r: &mut R, delim: u8) -> Result<usize> {
}
}
/// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it
/// to perform extra ways of reading.
///
/// For example, reading line-by-line is inefficient without using a buffer, so
/// if you want to read by line, you'll need `BufRead`, which includes a
/// [`read_line`] method as well as a [`lines`] iterator.
///
/// # Examples
///
/// A locked standard input implements `BufRead`:
///
/// ```no_run
/// use std::io;
/// use std::io::prelude::*;
///
/// let stdin = io::stdin();
/// for line in stdin.lock().lines() {
/// println!("{}", line?);
/// }
/// # std::io::Result::Ok(())
/// ```
///
/// If you have something that implements [`Read`], you can use the [`BufReader`
/// type][`BufReader`] to turn it into a `BufRead`.
///
/// For example, [`File`] implements [`Read`], but not `BufRead`.
/// [`BufReader`] to the rescue!
///
/// [`File`]: crate::fs::File
/// [`read_line`]: BufRead::read_line
/// [`lines`]: BufRead::lines
///
/// ```no_run
/// use std::io::{self, BufReader};
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// fn main() -> io::Result<()> {
/// let f = File::open("foo.txt")?;
/// let f = BufReader::new(f);
///
/// for line in f.lines() {
/// let line = line?;
/// println!("{line}");
/// }
///
/// Ok(())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(test), rustc_diagnostic_item = "IoBufRead")]
pub trait BufRead: Read {
@@ -2651,7 +2259,10 @@ pub trait BufRead: Read {
where
Self: Sized,
{
Split { buf: self, delim: byte }
Split {
buf: self,
delim: byte,
}
}
/// Returns an iterator over the lines of this reader.
@@ -2691,7 +2302,6 @@ pub trait BufRead: Read {
Lines { buf: self }
}
}
/// Adapter to chain together two readers.
///
/// This struct is generally created by calling [`chain`] on a reader.
@@ -2857,7 +2467,11 @@ impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
}
fn consume(&mut self, amt: usize) {
if !self.done_first { self.first.consume(amt) } else { self.second.consume(amt) }
if !self.done_first {
self.first.consume(amt)
} else {
self.second.consume(amt)
}
}
fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> {
@@ -2887,13 +2501,15 @@ impl<T, U> SizeHint for Chain<T, U> {
#[inline]
fn upper_bound(&self) -> Option<usize> {
match (SizeHint::upper_bound(&self.first), SizeHint::upper_bound(&self.second)) {
match (
SizeHint::upper_bound(&self.first),
SizeHint::upper_bound(&self.second),
) {
(Some(first), Some(second)) => first.checked_add(second),
_ => None,
}
}
}
/// Reader adapter which limits the bytes read from an underlying reader.
///
/// This struct is generally created by calling [`take`] on a reader.
@@ -3176,7 +2792,11 @@ impl<T: Seek> Seek for Take<T> {
self.limit = self.limit.wrapping_sub(offset as u64);
break;
}
let offset = if new_position > self.position() { i64::MAX } else { i64::MIN };
let offset = if new_position > self.position() {
i64::MAX
} else {
i64::MIN
};
self.inner.seek_relative(offset)?;
self.limit = self.limit.wrapping_sub(offset as u64);
}
@@ -3192,7 +2812,11 @@ impl<T: Seek> Seek for Take<T> {
}
fn seek_relative(&mut self, offset: i64) -> Result<()> {
if !self.position().checked_add_signed(offset).is_some_and(|p| p <= self.len) {
if !self
.position()
.checked_add_signed(offset)
.is_some_and(|p| p <= self.len)
{
return Err(ErrorKind::InvalidInput.into());
}
self.inner.seek_relative(offset)?;

0
crates/io/src/io/buffered/bufreader.rs → crates/std/src/io/buffered/bufreader.rs
View File

0
crates/io/src/io/buffered/bufreader/buffer.rs → crates/std/src/io/buffered/bufreader/buffer.rs
View File

0
crates/io/src/io/buffered/bufwriter.rs → crates/std/src/io/buffered/bufwriter.rs
View File

0
crates/io/src/io/buffered/linewriter.rs → crates/std/src/io/buffered/linewriter.rs
View File

0
crates/io/src/io/buffered/linewritershim.rs → crates/std/src/io/buffered/linewritershim.rs
View File

2
crates/io/src/io/buffered/mod.rs → crates/std/src/io/buffered/mod.rs
View File

@@ -5,6 +5,8 @@ mod bufwriter;
mod linewriter;
mod linewritershim;
#[cfg(test)]
mod tests;
#[stable(feature = "bufwriter_into_parts", since = "1.56.0")]
pub use bufwriter::WriterPanicked;

4
crates/io/src/io/copy.rs → crates/std/src/io/copy.rs
View File

@@ -1,11 +1,13 @@
use super::{BorrowedBuf, BufReader, BufWriter, DEFAULT_BUF_SIZE, Read, Result, Write};
use crate::alloc::Allocator;
use crate::cmp;
use crate::collections::VecDeque;
use alloc_crate::collections::VecDeque;
use crate::io::IoSlice;
use crate::mem::MaybeUninit;
use crate::sys::io::{CopyState, kernel_copy};
#[cfg(test)]
mod tests;
/// Copies the entire contents of a reader into a writer.
///

147
crates/std/src/io/copy/tests.rs Normal file
View File

@@ -0,0 +1,147 @@
use crate::cmp::{max, min};
use alloc_crate::collections::VecDeque;
use crate::io;
use crate::io::*;
#[test]
fn copy_copies() {
let mut r = repeat(0).take(4);
let mut w = sink();
assert_eq!(copy(&mut r, &mut w).unwrap(), 4);
let mut r = repeat(0).take(1 << 17);
assert_eq!(copy(&mut r as &mut dyn Read, &mut w as &mut dyn Write).unwrap(), 1 << 17);
}
struct ShortReader {
cap: usize,
read_size: usize,
observed_buffer: usize,
}
impl Read for ShortReader {
fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
let bytes = min(self.cap, self.read_size).min(buf.len());
self.cap -= bytes;
self.observed_buffer = max(self.observed_buffer, buf.len());
Ok(bytes)
}
}
struct WriteObserver {
observed_buffer: usize,
}
impl Write for WriteObserver {
fn write(&mut self, buf: &[u8]) -> Result<usize> {
self.observed_buffer = max(self.observed_buffer, buf.len());
Ok(buf.len())
}
fn flush(&mut self) -> Result<()> {
Ok(())
}
}
#[test]
fn copy_specializes_bufwriter() {
let cap = 117 * 1024;
let buf_sz = 16 * 1024;
let mut r = ShortReader { cap, observed_buffer: 0, read_size: 1337 };
let mut w = BufWriter::with_capacity(buf_sz, WriteObserver { observed_buffer: 0 });
assert_eq!(
copy(&mut r, &mut w).unwrap(),
cap as u64,
"expected the whole capacity to be copied"
);
assert_eq!(r.observed_buffer, buf_sz, "expected a large buffer to be provided to the reader");
assert!(w.get_mut().observed_buffer > DEFAULT_BUF_SIZE, "expected coalesced writes");
}
#[test]
fn copy_specializes_bufreader() {
let mut source = vec![0; 768 * 1024];
source[1] = 42;
let mut buffered = BufReader::with_capacity(256 * 1024, Cursor::new(&mut source));
let mut sink = Vec::new();
assert_eq!(crate::io::copy(&mut buffered, &mut sink).unwrap(), source.len() as u64);
assert_eq!(source.as_slice(), sink.as_slice());
let buf_sz = 71 * 1024;
assert!(buf_sz > DEFAULT_BUF_SIZE, "test precondition");
let mut buffered = BufReader::with_capacity(buf_sz, Cursor::new(&mut source));
let mut sink = WriteObserver { observed_buffer: 0 };
assert_eq!(crate::io::copy(&mut buffered, &mut sink).unwrap(), source.len() as u64);
assert_eq!(
sink.observed_buffer, buf_sz,
"expected a large buffer to be provided to the writer"
);
}
#[test]
fn copy_specializes_to_vec() {
let cap = DEFAULT_BUF_SIZE * 10;
let mut source = ShortReader { cap, observed_buffer: 0, read_size: DEFAULT_BUF_SIZE };
let mut sink = Vec::new();
let copied = io::copy(&mut source, &mut sink).unwrap();
assert_eq!(cap as u64, copied);
assert_eq!(sink.len() as u64, copied);
assert!(
source.observed_buffer > DEFAULT_BUF_SIZE,
"expected a large buffer to be provided to the reader, got {}",
source.observed_buffer
);
}
#[test]
fn copy_specializes_from_vecdeque() {
let mut source = VecDeque::with_capacity(100 * 1024);
for _ in 0..20 * 1024 {
source.push_front(0);
}
for _ in 0..20 * 1024 {
source.push_back(0);
}
let mut sink = WriteObserver { observed_buffer: 0 };
assert_eq!(40 * 1024u64, io::copy(&mut source, &mut sink).unwrap());
assert_eq!(20 * 1024, sink.observed_buffer);
}
#[test]
fn copy_specializes_from_slice() {
let mut source = [1; 60 * 1024].as_slice();
let mut sink = WriteObserver { observed_buffer: 0 };
assert_eq!(60 * 1024u64, io::copy(&mut source, &mut sink).unwrap());
assert_eq!(60 * 1024, sink.observed_buffer);
}
#[cfg(unix)]
mod io_benches {
use test::Bencher;
use crate::fs::{File, OpenOptions};
use crate::io::BufReader;
use crate::io::prelude::*;
#[bench]
#[cfg_attr(target_os = "emscripten", ignore)] // no /dev
fn bench_copy_buf_reader(b: &mut Bencher) {
let mut file_in = File::open("/dev/zero").expect("opening /dev/zero failed");
// use dyn to avoid specializations unrelated to readbuf
let dyn_in = &mut file_in as &mut dyn Read;
let mut reader = BufReader::with_capacity(256 * 1024, dyn_in.take(0));
let mut writer =
OpenOptions::new().write(true).open("/dev/null").expect("opening /dev/null failed");
const BYTES: u64 = 1024 * 1024;
b.bytes = BYTES;
b.iter(|| {
reader.get_mut().set_limit(BYTES);
crate::io::copy(&mut reader, &mut writer).unwrap()
});
}
}

2
crates/io/src/io/cursor.rs → crates/std/src/io/cursor.rs
View File

@@ -1,3 +1,5 @@
#[cfg(test)]
mod tests;
use crate::alloc::Allocator;
use crate::cmp;

567
crates/std/src/io/cursor/tests.rs Normal file
View File

@@ -0,0 +1,567 @@
use crate::io::prelude::*;
use crate::io::{Cursor, IoSlice, IoSliceMut, SeekFrom};
#[test]
fn test_vec_writer() {
let mut writer = Vec::new();
assert_eq!(writer.write(&[0]).unwrap(), 1);
assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
assert_eq!(
writer
.write_vectored(&[IoSlice::new(&[]), IoSlice::new(&[8, 9]), IoSlice::new(&[10])],)
.unwrap(),
3
);
let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
assert_eq!(writer, b);
}
#[test]
fn test_mem_writer() {
let mut writer = Cursor::new(Vec::new());
writer.set_position(10);
assert_eq!(writer.write(&[0]).unwrap(), 1);
assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
assert_eq!(
writer
.write_vectored(&[IoSlice::new(&[]), IoSlice::new(&[8, 9]), IoSlice::new(&[10])],)
.unwrap(),
3
);
let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
assert_eq!(&writer.get_ref()[..10], &[0; 10]);
assert_eq!(&writer.get_ref()[10..], b);
}
#[test]
fn test_mem_writer_preallocated() {
let mut writer = Cursor::new(vec![0, 0, 0, 0, 0, 0, 0, 0, 8, 9, 10]);
assert_eq!(writer.write(&[0]).unwrap(), 1);
assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
assert_eq!(&writer.get_ref()[..], b);
}
#[test]
fn test_mem_mut_writer() {
let mut vec = Vec::new();
let mut writer = Cursor::new(&mut vec);
assert_eq!(writer.write(&[0]).unwrap(), 1);
assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
assert_eq!(
writer
.write_vectored(&[IoSlice::new(&[]), IoSlice::new(&[8, 9]), IoSlice::new(&[10])],)
.unwrap(),
3
);
let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
assert_eq!(&writer.get_ref()[..], b);
}
fn test_slice_writer<T>(writer: &mut Cursor<T>)
where
T: AsRef<[u8]>,
Cursor<T>: Write,
{
assert_eq!(writer.position(), 0);
assert_eq!(writer.write(&[0]).unwrap(), 1);
assert_eq!(writer.position(), 1);
assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
assert_eq!(writer.position(), 8);
assert_eq!(writer.write(&[]).unwrap(), 0);
assert_eq!(writer.position(), 8);
assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
assert_eq!(writer.write(&[10]).unwrap(), 0);
let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
assert_eq!(writer.get_ref().as_ref(), b);
}
fn test_slice_writer_vectored<T>(writer: &mut Cursor<T>)
where
T: AsRef<[u8]>,
Cursor<T>: Write,
{
assert_eq!(writer.position(), 0);
assert_eq!(writer.write_vectored(&[IoSlice::new(&[0])]).unwrap(), 1);
assert_eq!(writer.position(), 1);
assert_eq!(
writer.write_vectored(&[IoSlice::new(&[1, 2, 3]), IoSlice::new(&[4, 5, 6, 7]),]).unwrap(),
7,
);
assert_eq!(writer.position(), 8);
assert_eq!(writer.write_vectored(&[]).unwrap(), 0);
assert_eq!(writer.position(), 8);
assert_eq!(writer.write_vectored(&[IoSlice::new(&[8, 9])]).unwrap(), 1);
assert_eq!(writer.write_vectored(&[IoSlice::new(&[10])]).unwrap(), 0);
let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
assert_eq!(writer.get_ref().as_ref(), b);
}
#[test]
fn test_box_slice_writer() {
let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
test_slice_writer(&mut writer);
}
#[test]
fn test_box_slice_writer_vectored() {
let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
test_slice_writer_vectored(&mut writer);
}
#[test]
fn test_array_writer() {
let mut writer = Cursor::new([0u8; 9]);
test_slice_writer(&mut writer);
}
#[test]
fn test_array_writer_vectored() {
let mut writer = Cursor::new([0u8; 9]);
test_slice_writer_vectored(&mut writer);
}
#[test]
fn test_buf_writer() {
let mut buf = [0 as u8; 9];
let mut writer = Cursor::new(&mut buf[..]);
test_slice_writer(&mut writer);
}
#[test]
fn test_buf_writer_vectored() {
let mut buf = [0 as u8; 9];
let mut writer = Cursor::new(&mut buf[..]);
test_slice_writer_vectored(&mut writer);
}
#[test]
fn test_buf_writer_seek() {
let mut buf = [0 as u8; 8];
{
let mut writer = Cursor::new(&mut buf[..]);
assert_eq!(writer.position(), 0);
assert_eq!(writer.write(&[1]).unwrap(), 1);
assert_eq!(writer.position(), 1);
assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2);
assert_eq!(writer.position(), 2);
assert_eq!(writer.write(&[2]).unwrap(), 1);
assert_eq!(writer.position(), 3);
assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1);
assert_eq!(writer.position(), 1);
assert_eq!(writer.write(&[3]).unwrap(), 1);
assert_eq!(writer.position(), 2);
assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
assert_eq!(writer.position(), 7);
assert_eq!(writer.write(&[4]).unwrap(), 1);
assert_eq!(writer.position(), 8);
}
let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4];
assert_eq!(buf, b);
}
#[test]
fn test_buf_writer_error() {
let mut buf = [0 as u8; 2];
let mut writer = Cursor::new(&mut buf[..]);
assert_eq!(writer.write(&[0]).unwrap(), 1);
assert_eq!(writer.write(&[0, 0]).unwrap(), 1);
assert_eq!(writer.write(&[0, 0]).unwrap(), 0);
}
#[test]
fn test_mem_reader() {
let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7]);
let mut buf = [];
assert_eq!(reader.read(&mut buf).unwrap(), 0);
assert_eq!(reader.position(), 0);
let mut buf = [0];
assert_eq!(reader.read(&mut buf).unwrap(), 1);
assert_eq!(reader.position(), 1);
let b: &[_] = &[0];
assert_eq!(buf, b);
let mut buf = [0; 4];
assert_eq!(reader.read(&mut buf).unwrap(), 4);
assert_eq!(reader.position(), 5);
let b: &[_] = &[1, 2, 3, 4];
assert_eq!(buf, b);
assert_eq!(reader.read(&mut buf).unwrap(), 3);
let b: &[_] = &[5, 6, 7];
assert_eq!(&buf[..3], b);
assert_eq!(reader.read(&mut buf).unwrap(), 0);
}
#[test]
fn test_mem_reader_vectored() {
let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7]);
let mut buf = [];
assert_eq!(reader.read_vectored(&mut [IoSliceMut::new(&mut buf)]).unwrap(), 0);
assert_eq!(reader.position(), 0);
let mut buf = [0];
assert_eq!(
reader.read_vectored(&mut [IoSliceMut::new(&mut []), IoSliceMut::new(&mut buf),]).unwrap(),
1,
);
assert_eq!(reader.position(), 1);
let b: &[_] = &[0];
assert_eq!(buf, b);
let mut buf1 = [0; 4];
let mut buf2 = [0; 4];
assert_eq!(
reader
.read_vectored(&mut [IoSliceMut::new(&mut buf1), IoSliceMut::new(&mut buf2),])
.unwrap(),
7,
);
let b1: &[_] = &[1, 2, 3, 4];
let b2: &[_] = &[5, 6, 7];
assert_eq!(buf1, b1);
assert_eq!(&buf2[..3], b2);
assert_eq!(reader.read(&mut buf).unwrap(), 0);
}
#[test]
fn test_boxed_slice_reader() {
let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7].into_boxed_slice());
let mut buf = [];
assert_eq!(reader.read(&mut buf).unwrap(), 0);
assert_eq!(reader.position(), 0);
let mut buf = [0];
assert_eq!(reader.read(&mut buf).unwrap(), 1);
assert_eq!(reader.position(), 1);
let b: &[_] = &[0];
assert_eq!(buf, b);
let mut buf = [0; 4];
assert_eq!(reader.read(&mut buf).unwrap(), 4);
assert_eq!(reader.position(), 5);
let b: &[_] = &[1, 2, 3, 4];
assert_eq!(buf, b);
assert_eq!(reader.read(&mut buf).unwrap(), 3);
let b: &[_] = &[5, 6, 7];
assert_eq!(&buf[..3], b);
assert_eq!(reader.read(&mut buf).unwrap(), 0);
}
#[test]
fn test_boxed_slice_reader_vectored() {
let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7].into_boxed_slice());
let mut buf = [];
assert_eq!(reader.read_vectored(&mut [IoSliceMut::new(&mut buf)]).unwrap(), 0);
assert_eq!(reader.position(), 0);
let mut buf = [0];
assert_eq!(
reader.read_vectored(&mut [IoSliceMut::new(&mut []), IoSliceMut::new(&mut buf),]).unwrap(),
1,
);
assert_eq!(reader.position(), 1);
let b: &[_] = &[0];
assert_eq!(buf, b);
let mut buf1 = [0; 4];
let mut buf2 = [0; 4];
assert_eq!(
reader
.read_vectored(&mut [IoSliceMut::new(&mut buf1), IoSliceMut::new(&mut buf2)],)
.unwrap(),
7,
);
let b1: &[_] = &[1, 2, 3, 4];
let b2: &[_] = &[5, 6, 7];
assert_eq!(buf1, b1);
assert_eq!(&buf2[..3], b2);
assert_eq!(reader.read(&mut buf).unwrap(), 0);
}
#[test]
fn read_to_end() {
let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7]);
let mut v = Vec::new();
reader.read_to_end(&mut v).unwrap();
assert_eq!(v, [0, 1, 2, 3, 4, 5, 6, 7]);
}
#[test]
fn test_slice_reader() {
let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
let reader = &mut &in_buf[..];
let mut buf = [];
assert_eq!(reader.read(&mut buf).unwrap(), 0);
let mut buf = [0];
assert_eq!(reader.read(&mut buf).unwrap(), 1);
assert_eq!(reader.len(), 7);
let b: &[_] = &[0];
assert_eq!(&buf[..], b);
let mut buf = [0; 4];
assert_eq!(reader.read(&mut buf).unwrap(), 4);
assert_eq!(reader.len(), 3);
let b: &[_] = &[1, 2, 3, 4];
assert_eq!(&buf[..], b);
assert_eq!(reader.read(&mut buf).unwrap(), 3);
let b: &[_] = &[5, 6, 7];
assert_eq!(&buf[..3], b);
assert_eq!(reader.read(&mut buf).unwrap(), 0);
}
#[test]
fn test_slice_reader_vectored() {
let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
let reader = &mut &in_buf[..];
let mut buf = [];
assert_eq!(reader.read_vectored(&mut [IoSliceMut::new(&mut buf)]).unwrap(), 0);
let mut buf = [0];
assert_eq!(
reader.read_vectored(&mut [IoSliceMut::new(&mut []), IoSliceMut::new(&mut buf),]).unwrap(),
1,
);
assert_eq!(reader.len(), 7);
let b: &[_] = &[0];
assert_eq!(buf, b);
let mut buf1 = [0; 4];
let mut buf2 = [0; 4];
assert_eq!(
reader
.read_vectored(&mut [IoSliceMut::new(&mut buf1), IoSliceMut::new(&mut buf2)],)
.unwrap(),
7,
);
let b1: &[_] = &[1, 2, 3, 4];
let b2: &[_] = &[5, 6, 7];
assert_eq!(buf1, b1);
assert_eq!(&buf2[..3], b2);
assert_eq!(reader.read(&mut buf).unwrap(), 0);
}
#[test]
fn test_read_exact() {
let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
let reader = &mut &in_buf[..];
let mut buf = [];
assert!(reader.read_exact(&mut buf).is_ok());
let mut buf = [8];
assert!(reader.read_exact(&mut buf).is_ok());
assert_eq!(buf[0], 0);
assert_eq!(reader.len(), 7);
let mut buf = [0, 0, 0, 0, 0, 0, 0];
assert!(reader.read_exact(&mut buf).is_ok());
assert_eq!(buf, [1, 2, 3, 4, 5, 6, 7]);
assert_eq!(reader.len(), 0);
let mut buf = [0];
assert!(reader.read_exact(&mut buf).is_err());
}
#[test]
fn test_buf_reader() {
let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
let mut reader = Cursor::new(&in_buf[..]);
let mut buf = [];
assert_eq!(reader.read(&mut buf).unwrap(), 0);
assert_eq!(reader.position(), 0);
let mut buf = [0];
assert_eq!(reader.read(&mut buf).unwrap(), 1);
assert_eq!(reader.position(), 1);
let b: &[_] = &[0];
assert_eq!(buf, b);
let mut buf = [0; 4];
assert_eq!(reader.read(&mut buf).unwrap(), 4);
assert_eq!(reader.position(), 5);
let b: &[_] = &[1, 2, 3, 4];
assert_eq!(buf, b);
assert_eq!(reader.read(&mut buf).unwrap(), 3);
let b: &[_] = &[5, 6, 7];
assert_eq!(&buf[..3], b);
assert_eq!(reader.read(&mut buf).unwrap(), 0);
}
#[test]
fn seek_past_end() {
let buf = [0xff];
let mut r = Cursor::new(&buf[..]);
assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
assert_eq!(r.read(&mut [0]).unwrap(), 0);
let mut r = Cursor::new(vec![10]);
assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
assert_eq!(r.read(&mut [0]).unwrap(), 0);
let mut buf = [0];
let mut r = Cursor::new(&mut buf[..]);
assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
assert_eq!(r.write(&[3]).unwrap(), 0);
let mut r = Cursor::new(vec![10].into_boxed_slice());
assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
assert_eq!(r.write(&[3]).unwrap(), 0);
}
#[test]
fn seek_past_i64() {
let buf = [0xff];
let mut r = Cursor::new(&buf[..]);
assert_eq!(r.seek(SeekFrom::Start(6)).unwrap(), 6);
assert_eq!(r.seek(SeekFrom::Current(0x7ffffffffffffff0)).unwrap(), 0x7ffffffffffffff6);
assert_eq!(r.seek(SeekFrom::Current(0x10)).unwrap(), 0x8000000000000006);
assert_eq!(r.seek(SeekFrom::Current(0)).unwrap(), 0x8000000000000006);
assert!(r.seek(SeekFrom::Current(0x7ffffffffffffffd)).is_err());
assert_eq!(r.seek(SeekFrom::Current(-0x8000000000000000)).unwrap(), 6);
let mut r = Cursor::new(vec![10]);
assert_eq!(r.seek(SeekFrom::Start(6)).unwrap(), 6);
assert_eq!(r.seek(SeekFrom::Current(0x7ffffffffffffff0)).unwrap(), 0x7ffffffffffffff6);
assert_eq!(r.seek(SeekFrom::Current(0x10)).unwrap(), 0x8000000000000006);
assert_eq!(r.seek(SeekFrom::Current(0)).unwrap(), 0x8000000000000006);
assert!(r.seek(SeekFrom::Current(0x7ffffffffffffffd)).is_err());
assert_eq!(r.seek(SeekFrom::Current(-0x8000000000000000)).unwrap(), 6);
let mut buf = [0];
let mut r = Cursor::new(&mut buf[..]);
assert_eq!(r.seek(SeekFrom::Start(6)).unwrap(), 6);
assert_eq!(r.seek(SeekFrom::Current(0x7ffffffffffffff0)).unwrap(), 0x7ffffffffffffff6);
assert_eq!(r.seek(SeekFrom::Current(0x10)).unwrap(), 0x8000000000000006);
assert_eq!(r.seek(SeekFrom::Current(0)).unwrap(), 0x8000000000000006);
assert!(r.seek(SeekFrom::Current(0x7ffffffffffffffd)).is_err());
assert_eq!(r.seek(SeekFrom::Current(-0x8000000000000000)).unwrap(), 6);
let mut r = Cursor::new(vec![10].into_boxed_slice());
assert_eq!(r.seek(SeekFrom::Start(6)).unwrap(), 6);
assert_eq!(r.seek(SeekFrom::Current(0x7ffffffffffffff0)).unwrap(), 0x7ffffffffffffff6);
assert_eq!(r.seek(SeekFrom::Current(0x10)).unwrap(), 0x8000000000000006);
assert_eq!(r.seek(SeekFrom::Current(0)).unwrap(), 0x8000000000000006);
assert!(r.seek(SeekFrom::Current(0x7ffffffffffffffd)).is_err());
assert_eq!(r.seek(SeekFrom::Current(-0x8000000000000000)).unwrap(), 6);
}
#[test]
fn seek_before_0() {
let buf = [0xff];
let mut r = Cursor::new(&buf[..]);
assert!(r.seek(SeekFrom::End(-2)).is_err());
let mut r = Cursor::new(vec![10]);
assert!(r.seek(SeekFrom::End(-2)).is_err());
let mut buf = [0];
let mut r = Cursor::new(&mut buf[..]);
assert!(r.seek(SeekFrom::End(-2)).is_err());
let mut r = Cursor::new(vec![10].into_boxed_slice());
assert!(r.seek(SeekFrom::End(-2)).is_err());
}
#[test]
fn test_seekable_mem_writer() {
let mut writer = Cursor::new(Vec::<u8>::new());
assert_eq!(writer.position(), 0);
assert_eq!(writer.write(&[0]).unwrap(), 1);
assert_eq!(writer.position(), 1);
assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
assert_eq!(writer.position(), 8);
let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
assert_eq!(&writer.get_ref()[..], b);
assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0);
assert_eq!(writer.position(), 0);
assert_eq!(writer.write(&[3, 4]).unwrap(), 2);
let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7];
assert_eq!(&writer.get_ref()[..], b);
assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3);
assert_eq!(writer.write(&[0, 1]).unwrap(), 2);
let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7];
assert_eq!(&writer.get_ref()[..], b);
assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
assert_eq!(writer.write(&[1, 2]).unwrap(), 2);
let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2];
assert_eq!(&writer.get_ref()[..], b);
assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10);
assert_eq!(writer.write(&[1]).unwrap(), 1);
let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1];
assert_eq!(&writer.get_ref()[..], b);
}
#[test]
fn vec_seek_past_end() {
let mut r = Cursor::new(Vec::new());
assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
assert_eq!(r.write(&[3]).unwrap(), 1);
}
#[test]
fn vec_seek_before_0() {
let mut r = Cursor::new(Vec::new());
assert!(r.seek(SeekFrom::End(-2)).is_err());
}
#[test]
#[cfg(target_pointer_width = "32")]
fn vec_seek_and_write_past_usize_max() {
let mut c = Cursor::new(Vec::new());
c.set_position(usize::MAX as u64 + 1);
assert!(c.write_all(&[1, 2, 3]).is_err());
}
#[test]
fn test_partial_eq() {
assert_eq!(Cursor::new(Vec::<u8>::new()), Cursor::new(Vec::<u8>::new()));
}
#[test]
fn test_eq() {
struct AssertEq<T: Eq>(pub T);
let _: AssertEq<Cursor<Vec<u8>>> = AssertEq(Cursor::new(Vec::new()));
}
#[allow(dead_code)]
fn const_cursor() {
const CURSOR: Cursor<&[u8]> = Cursor::new(&[0]);
const _: &&[u8] = CURSOR.get_ref();
const _: u64 = CURSOR.position();
}
#[bench]
fn bench_write_vec(b: &mut test::Bencher) {
let slice = &[1; 128];
b.iter(|| {
let mut buf = b"some random data to overwrite".to_vec();
let mut cursor = Cursor::new(&mut buf);
let _ = cursor.write_all(slice);
test::black_box(&cursor);
})
}
#[bench]
fn bench_write_vec_vectored(b: &mut test::Bencher) {
let slices = [
IoSlice::new(&[1; 128]),
IoSlice::new(&[2; 256]),
IoSlice::new(&[3; 512]),
IoSlice::new(&[4; 1024]),
IoSlice::new(&[5; 2048]),
IoSlice::new(&[6; 4096]),
IoSlice::new(&[7; 8192]),
IoSlice::new(&[8; 8192 * 2]),
];
b.iter(|| {
let mut buf = b"some random data to overwrite".to_vec();
let mut cursor = Cursor::new(&mut buf);
let mut slices = slices;
let _ = cursor.write_all_vectored(&mut slices);
test::black_box(&cursor);
})
}

2
crates/io/src/io/error.rs → crates/std/src/io/error.rs
View File

@@ -1,3 +1,5 @@
#[cfg(test)]
mod tests;
// On 64-bit platforms, `io::Error` may use a bit-packed representation to
// reduce size. However, this representation assumes that error codes are

0
crates/io/src/io/error/repr_bitpacked.rs → crates/std/src/io/error/repr_bitpacked.rs
View File

0
crates/io/src/io/error/repr_unpacked.rs → crates/std/src/io/error/repr_unpacked.rs
View File

191
crates/std/src/io/error/tests.rs Normal file
View File

@@ -0,0 +1,191 @@
use super::{Custom, Error, ErrorData, ErrorKind, Repr, SimpleMessage, const_error};
use crate::sys::io::{decode_error_kind, error_string};
use crate::{assert_matches, error, fmt};
#[test]
fn test_size() {
assert!(size_of::<Error>() <= size_of::<[usize; 2]>());
}
#[test]
fn test_debug_error() {
let code = 6;
let msg = error_string(code);
let kind = decode_error_kind(code);
let err = Error {
repr: Repr::new_custom(Box::new(Custom {
kind: ErrorKind::InvalidInput,
error: Box::new(Error { repr: super::Repr::new_os(code) }),
})),
};
let expected = format!(
"Custom {{ \
kind: InvalidInput, \
error: Os {{ \
code: {:?}, \
kind: {:?}, \
message: {:?} \
}} \
}}",
code, kind, msg
);
assert_eq!(format!("{err:?}"), expected);
}
#[test]
fn test_downcasting() {
#[derive(Debug)]
struct TestError;
impl fmt::Display for TestError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("asdf")
}
}
impl error::Error for TestError {}
// we have to call all of these UFCS style right now since method
// resolution won't implicitly drop the Send+Sync bounds
let mut err = Error::new(ErrorKind::Other, TestError);
assert!(err.get_ref().unwrap().is::<TestError>());
assert_eq!("asdf", err.get_ref().unwrap().to_string());
assert!(err.get_mut().unwrap().is::<TestError>());
let extracted = err.into_inner().unwrap();
extracted.downcast::<TestError>().unwrap();
}
#[test]
fn test_const() {
const E: Error = const_error!(ErrorKind::NotFound, "hello");
assert_eq!(E.kind(), ErrorKind::NotFound);
assert_eq!(E.to_string(), "hello");
assert!(format!("{E:?}").contains("\"hello\""));
assert!(format!("{E:?}").contains("NotFound"));
}
#[test]
fn test_os_packing() {
for code in -20..20 {
let e = Error::from_raw_os_error(code);
assert_eq!(e.raw_os_error(), Some(code));
assert_matches!(
e.repr.data(),
ErrorData::Os(c) if c == code,
);
}
}
#[test]
fn test_errorkind_packing() {
assert_eq!(Error::from(ErrorKind::NotFound).kind(), ErrorKind::NotFound);
assert_eq!(Error::from(ErrorKind::PermissionDenied).kind(), ErrorKind::PermissionDenied);
assert_eq!(Error::from(ErrorKind::Uncategorized).kind(), ErrorKind::Uncategorized);
// Check that the innards look like what we want.
assert_matches!(
Error::from(ErrorKind::OutOfMemory).repr.data(),
ErrorData::Simple(ErrorKind::OutOfMemory),
);
}
#[test]
fn test_simple_message_packing() {
use super::ErrorKind::*;
use super::SimpleMessage;
macro_rules! check_simple_msg {
($err:expr, $kind:ident, $msg:literal) => {{
let e = &$err;
// Check that the public api is right.
assert_eq!(e.kind(), $kind);
assert!(format!("{e:?}").contains($msg));
// and we got what we expected
assert_matches!(
e.repr.data(),
ErrorData::SimpleMessage(SimpleMessage { kind: $kind, message: $msg })
);
}};
}
let not_static = const_error!(Uncategorized, "not a constant!");
check_simple_msg!(not_static, Uncategorized, "not a constant!");
const CONST: Error = const_error!(NotFound, "definitely a constant!");
check_simple_msg!(CONST, NotFound, "definitely a constant!");
static STATIC: Error = const_error!(BrokenPipe, "a constant, sort of!");
check_simple_msg!(STATIC, BrokenPipe, "a constant, sort of!");
}
#[derive(Debug, PartialEq)]
struct Bojji(bool);
impl error::Error for Bojji {}
impl fmt::Display for Bojji {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "ah! {:?}", self)
}
}
#[test]
fn test_custom_error_packing() {
use super::Custom;
let test = Error::new(ErrorKind::Uncategorized, Bojji(true));
assert_matches!(
test.repr.data(),
ErrorData::Custom(Custom {
kind: ErrorKind::Uncategorized,
error,
}) if error.downcast_ref::<Bojji>().as_deref() == Some(&Bojji(true)),
);
}
#[derive(Debug)]
struct E;
impl fmt::Display for E {
fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
Ok(())
}
}
impl error::Error for E {}
#[test]
fn test_std_io_error_downcast() {
// Case 1: custom error, downcast succeeds
let io_error = Error::new(ErrorKind::Other, Bojji(true));
let e: Bojji = io_error.downcast().unwrap();
assert!(e.0);
// Case 2: custom error, downcast fails
let io_error = Error::new(ErrorKind::Other, Bojji(true));
let io_error = io_error.downcast::<E>().unwrap_err();
// ensures that the custom error is intact
assert_eq!(ErrorKind::Other, io_error.kind());
let e: Bojji = io_error.downcast().unwrap();
assert!(e.0);
// Case 3: os error
let errno = 20;
let io_error = Error::from_raw_os_error(errno);
let io_error = io_error.downcast::<E>().unwrap_err();
assert_eq!(errno, io_error.raw_os_error().unwrap());
// Case 4: simple
let kind = ErrorKind::OutOfMemory;
let io_error: Error = kind.into();
let io_error = io_error.downcast::<E>().unwrap_err();
assert_eq!(kind, io_error.kind());
// Case 5: simple message
const SIMPLE_MESSAGE: SimpleMessage =
SimpleMessage { kind: ErrorKind::Other, message: "simple message error test" };
let io_error = Error::from_static_message(&SIMPLE_MESSAGE);
let io_error = io_error.downcast::<E>().unwrap_err();
assert_eq!(SIMPLE_MESSAGE.kind, io_error.kind());
assert_eq!(SIMPLE_MESSAGE.message, format!("{io_error}"));
}

4
crates/io/src/io/impls.rs → crates/std/src/io/impls.rs
View File

@@ -1,6 +1,8 @@
#[cfg(test)]
mod tests;
use crate::alloc::Allocator;
use crate::collections::VecDeque;
use alloc_crate::collections::VecDeque;
use crate::io::{self, BorrowedCursor, BufRead, IoSlice, IoSliceMut, Read, Seek, SeekFrom, Write};
use crate::{cmp, fmt, mem, str};

57
crates/std/src/io/impls/tests.rs Normal file
View File

@@ -0,0 +1,57 @@
use crate::io::prelude::*;
#[bench]
fn bench_read_slice(b: &mut test::Bencher) {
let buf = [5; 1024];
let mut dst = [0; 128];
b.iter(|| {
let mut rd = &buf[..];
for _ in 0..8 {
let _ = rd.read(&mut dst);
test::black_box(&dst);
}
})
}
#[bench]
fn bench_write_slice(b: &mut test::Bencher) {
let mut buf = [0; 1024];
let src = [5; 128];
b.iter(|| {
let mut wr = &mut buf[..];
for _ in 0..8 {
let _ = wr.write_all(&src);
test::black_box(&wr);
}
})
}
#[bench]
fn bench_read_vec(b: &mut test::Bencher) {
let buf = vec![5; 1024];
let mut dst = [0; 128];
b.iter(|| {
let mut rd = &buf[..];
for _ in 0..8 {
let _ = rd.read(&mut dst);
test::black_box(&dst);
}
})
}
#[bench]
fn bench_write_vec(b: &mut test::Bencher) {
let mut buf = Vec::with_capacity(1024);
let src = [5; 128];
b.iter(|| {
let mut wr = &mut buf[..];
for _ in 0..8 {
let _ = wr.write_all(&src);
test::black_box(&wr);
}
})
}

295
crates/std/src/io/pipe.rs Normal file
View File

@@ -0,0 +1,295 @@
use crate::io;
use crate::sys::{FromInner, IntoInner, pipe as imp};
/// Creates an anonymous pipe.
///
/// # Behavior
///
/// A pipe is a one-way data channel provided by the OS, which works across processes. A pipe is
/// typically used to communicate between two or more separate processes, as there are better,
/// faster ways to communicate within a single process.
///
/// In particular:
///
/// * A read on a [`PipeReader`] blocks until the pipe is non-empty.
/// * A write on a [`PipeWriter`] blocks when the pipe is full.
/// * When all copies of a [`PipeWriter`] are closed, a read on the corresponding [`PipeReader`]
/// returns EOF.
/// * [`PipeWriter`] can be shared, and multiple processes or threads can write to it at once, but
/// writes (above a target-specific threshold) may have their data interleaved.
/// * [`PipeReader`] can be shared, and multiple processes or threads can read it at once. Any
/// given byte will only get consumed by one reader. There are no guarantees about data
/// interleaving.
/// * Portable applications cannot assume any atomicity of messages larger than a single byte.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `pipe` function on Unix and the
/// `CreatePipe` function on Windows.
///
/// Note that this [may change in the future][changes].
///
/// # Capacity
///
/// Pipe capacity is platform dependent. To quote the Linux [man page]:
///
/// > Different implementations have different limits for the pipe capacity. Applications should
/// > not rely on a particular capacity: an application should be designed so that a reading process
/// > consumes data as soon as it is available, so that a writing process does not remain blocked.
///
/// # Example
///
/// ```no_run
/// # #[cfg(miri)] fn main() {}
/// # #[cfg(not(miri))]
/// # fn main() -> std::io::Result<()> {
/// use std::io::{Read, Write, pipe};
/// use std::process::Command;
/// let (ping_reader, mut ping_writer) = pipe()?;
/// let (mut pong_reader, pong_writer) = pipe()?;
///
/// // Spawn a child process that echoes its input.
/// let mut echo_command = Command::new("cat");
/// echo_command.stdin(ping_reader);
/// echo_command.stdout(pong_writer);
/// let mut echo_child = echo_command.spawn()?;
///
/// // Send input to the child process. Note that because we're writing all the input before we
/// // read any output, this could deadlock if the child's input and output pipe buffers both
/// // filled up. Those buffers are usually at least a few KB, so "hello" is fine, but for longer
/// // inputs we'd need to read and write at the same time, e.g. using threads.
/// ping_writer.write_all(b"hello")?;
///
/// // `cat` exits when it reads EOF from stdin, but that can't happen while any ping writer
/// // remains open. We need to drop our ping writer, or read_to_string will deadlock below.
/// drop(ping_writer);
///
/// // The pong reader can't report EOF while any pong writer remains open. Our Command object is
/// // holding a pong writer, and again read_to_string will deadlock if we don't drop it.
/// drop(echo_command);
///
/// let mut buf = String::new();
/// // Block until `cat` closes its stdout (a pong writer).
/// pong_reader.read_to_string(&mut buf)?;
/// assert_eq!(&buf, "hello");
///
/// // At this point we know `cat` has exited, but we still need to wait to clean up the "zombie".
/// echo_child.wait()?;
/// # Ok(())
/// # }
/// ```
/// [changes]: io#platform-specific-behavior
/// [man page]: https://man7.org/linux/man-pages/man7/pipe.7.html
#[stable(feature = "anonymous_pipe", since = "1.87.0")]
#[inline]
pub fn pipe() -> io::Result<(PipeReader, PipeWriter)> {
imp::pipe().map(|(reader, writer)| (PipeReader(reader), PipeWriter(writer)))
}
/// Read end of an anonymous pipe.
#[stable(feature = "anonymous_pipe", since = "1.87.0")]
#[derive(Debug)]
pub struct PipeReader(pub(crate) imp::Pipe);
/// Write end of an anonymous pipe.
#[stable(feature = "anonymous_pipe", since = "1.87.0")]
#[derive(Debug)]
pub struct PipeWriter(pub(crate) imp::Pipe);
impl FromInner<imp::Pipe> for PipeReader {
fn from_inner(inner: imp::Pipe) -> Self {
Self(inner)
}
}
impl IntoInner<imp::Pipe> for PipeReader {
fn into_inner(self) -> imp::Pipe {
self.0
}
}
impl FromInner<imp::Pipe> for PipeWriter {
fn from_inner(inner: imp::Pipe) -> Self {
Self(inner)
}
}
impl IntoInner<imp::Pipe> for PipeWriter {
fn into_inner(self) -> imp::Pipe {
self.0
}
}
impl PipeReader {
/// Creates a new [`PipeReader`] instance that shares the same underlying file description.
///
/// # Examples
///
/// ```no_run
/// # #[cfg(miri)] fn main() {}
/// # #[cfg(not(miri))]
/// # fn main() -> std::io::Result<()> {
/// use std::fs;
/// use std::io::{pipe, Write};
/// use std::process::Command;
/// const NUM_SLOT: u8 = 2;
/// const NUM_PROC: u8 = 5;
/// const OUTPUT: &str = "work.txt";
///
/// let mut jobs = vec![];
/// let (reader, mut writer) = pipe()?;
///
/// // Write NUM_SLOT characters the pipe.
/// writer.write_all(&[b'|'; NUM_SLOT as usize])?;
///
/// // Spawn several processes that read a character from the pipe, do some work, then
/// // write back to the pipe. When the pipe is empty, the processes block, so only
/// // NUM_SLOT processes can be working at any given time.
/// for _ in 0..NUM_PROC {
/// jobs.push(
/// Command::new("bash")
/// .args(["-c",
/// &format!(
/// "read -n 1\n\
/// echo -n 'x' >> '{OUTPUT}'\n\
/// echo -n '|'",
/// ),
/// ])
/// .stdin(reader.try_clone()?)
/// .stdout(writer.try_clone()?)
/// .spawn()?,
/// );
/// }
///
/// // Wait for all jobs to finish.
/// for mut job in jobs {
/// job.wait()?;
/// }
///
/// // Check our work and clean up.
/// let xs = fs::read_to_string(OUTPUT)?;
/// fs::remove_file(OUTPUT)?;
/// assert_eq!(xs, "x".repeat(NUM_PROC.into()));
/// # Ok(())
/// # }
/// ```
#[stable(feature = "anonymous_pipe", since = "1.87.0")]
pub fn try_clone(&self) -> io::Result<Self> {
self.0.try_clone().map(Self)
}
}
impl PipeWriter {
/// Creates a new [`PipeWriter`] instance that shares the same underlying file description.
///
/// # Examples
///
/// ```no_run
/// # #[cfg(miri)] fn main() {}
/// # #[cfg(not(miri))]
/// # fn main() -> std::io::Result<()> {
/// use std::process::Command;
/// use std::io::{pipe, Read};
/// let (mut reader, writer) = pipe()?;
///
/// // Spawn a process that writes to stdout and stderr.
/// let mut peer = Command::new("bash")
/// .args([
/// "-c",
/// "echo -n foo\n\
/// echo -n bar >&2"
/// ])
/// .stdout(writer.try_clone()?)
/// .stderr(writer)
/// .spawn()?;
///
/// // Read and check the result.
/// let mut msg = String::new();
/// reader.read_to_string(&mut msg)?;
/// assert_eq!(&msg, "foobar");
///
/// peer.wait()?;
/// # Ok(())
/// # }
/// ```
#[stable(feature = "anonymous_pipe", since = "1.87.0")]
pub fn try_clone(&self) -> io::Result<Self> {
self.0.try_clone().map(Self)
}
}
#[stable(feature = "anonymous_pipe", since = "1.87.0")]
impl io::Read for &PipeReader {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
self.0.read(buf)
}
fn read_vectored(&mut self, bufs: &mut [io::IoSliceMut<'_>]) -> io::Result<usize> {
self.0.read_vectored(bufs)
}
#[inline]
fn is_read_vectored(&self) -> bool {
self.0.is_read_vectored()
}
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
self.0.read_to_end(buf)
}
fn read_buf(&mut self, buf: io::BorrowedCursor<'_>) -> io::Result<()> {
self.0.read_buf(buf)
}
}
#[stable(feature = "anonymous_pipe", since = "1.87.0")]
impl io::Read for PipeReader {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
self.0.read(buf)
}
fn read_vectored(&mut self, bufs: &mut [io::IoSliceMut<'_>]) -> io::Result<usize> {
self.0.read_vectored(bufs)
}
#[inline]
fn is_read_vectored(&self) -> bool {
self.0.is_read_vectored()
}
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
self.0.read_to_end(buf)
}
fn read_buf(&mut self, buf: io::BorrowedCursor<'_>) -> io::Result<()> {
self.0.read_buf(buf)
}
}
#[stable(feature = "anonymous_pipe", since = "1.87.0")]
impl io::Write for &PipeWriter {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
self.0.write(buf)
}
#[inline]
fn flush(&mut self) -> io::Result<()> {
Ok(())
}
fn write_vectored(&mut self, bufs: &[io::IoSlice<'_>]) -> io::Result<usize> {
self.0.write_vectored(bufs)
}
#[inline]
fn is_write_vectored(&self) -> bool {
self.0.is_write_vectored()
}
}
#[stable(feature = "anonymous_pipe", since = "1.87.0")]
impl io::Write for PipeWriter {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
self.0.write(buf)
}
#[inline]
fn flush(&mut self) -> io::Result<()> {
Ok(())
}
fn write_vectored(&mut self, bufs: &[io::IoSlice<'_>]) -> io::Result<usize> {
self.0.write_vectored(bufs)
}
#[inline]
fn is_write_vectored(&self) -> bool {
self.0.is_write_vectored()
}
}

18
crates/std/src/io/pipe/tests.rs Normal file
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@@ -0,0 +1,18 @@
use crate::io::{Read, Write, pipe};
#[test]
#[cfg(all(any(unix, windows), not(miri)))]
fn pipe_creation_clone_and_rw() {
let (rx, tx) = pipe().unwrap();
tx.try_clone().unwrap().write_all(b"12345").unwrap();
drop(tx);
let mut rx2 = rx.try_clone().unwrap();
drop(rx);
let mut s = String::new();
rx2.read_to_string(&mut s).unwrap();
drop(rx2);
assert_eq!(s, "12345");
}

0
crates/io/src/io/prelude.rs → crates/std/src/io/prelude.rs
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1292
crates/std/src/io/stdio.rs Normal file
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947
crates/std/src/io/tests.rs Normal file
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@@ -0,0 +1,947 @@
use super::{BorrowedBuf, Cursor, SeekFrom, repeat};
use crate::cmp::{self, min};
use crate::io::{
self, BufRead, BufReader, DEFAULT_BUF_SIZE, IoSlice, IoSliceMut, Read, Seek, Write,
};
use crate::mem::MaybeUninit;
use crate::ops::Deref;
#[test]
fn read_until() {
let mut buf = Cursor::new(&b"12"[..]);
let mut v = Vec::new();
assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
assert_eq!(v, b"12");
let mut buf = Cursor::new(&b"1233"[..]);
let mut v = Vec::new();
assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
assert_eq!(v, b"123");
v.truncate(0);
assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
assert_eq!(v, b"3");
v.truncate(0);
assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
assert_eq!(v, []);
}
#[test]
fn skip_until() {
let bytes: &[u8] = b"read\0ignore\0read\0ignore\0read\0ignore\0";
let mut reader = BufReader::new(bytes);
// read from the bytes, alternating between
// consuming `read\0`s and skipping `ignore\0`s
loop {
// consume `read\0`
let mut out = Vec::new();
let read = reader.read_until(0, &mut out).unwrap();
if read == 0 {
// eof
break;
} else {
assert_eq!(out, b"read\0");
assert_eq!(read, b"read\0".len());
}
// skip past `ignore\0`
let skipped = reader.skip_until(0).unwrap();
assert_eq!(skipped, b"ignore\0".len());
}
// ensure we are at the end of the byte slice and that we can skip no further
// also ensure skip_until matches the behavior of read_until at EOF
let skipped = reader.skip_until(0).unwrap();
assert_eq!(skipped, 0);
}
#[test]
fn split() {
let buf = Cursor::new(&b"12"[..]);
let mut s = buf.split(b'3');
assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
assert!(s.next().is_none());
let buf = Cursor::new(&b"1233"[..]);
let mut s = buf.split(b'3');
assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
assert_eq!(s.next().unwrap().unwrap(), vec![]);
assert!(s.next().is_none());
}
#[test]
fn read_line() {
let mut buf = Cursor::new(&b"12"[..]);
let mut v = String::new();
assert_eq!(buf.read_line(&mut v).unwrap(), 2);
assert_eq!(v, "12");
let mut buf = Cursor::new(&b"12\n\n"[..]);
let mut v = String::new();
assert_eq!(buf.read_line(&mut v).unwrap(), 3);
assert_eq!(v, "12\n");
v.truncate(0);
assert_eq!(buf.read_line(&mut v).unwrap(), 1);
assert_eq!(v, "\n");
v.truncate(0);
assert_eq!(buf.read_line(&mut v).unwrap(), 0);
assert_eq!(v, "");
}
#[test]
fn lines() {
let buf = Cursor::new(&b"12\r"[..]);
let mut s = buf.lines();
assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
assert!(s.next().is_none());
let buf = Cursor::new(&b"12\r\n\n"[..]);
let mut s = buf.lines();
assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
assert_eq!(s.next().unwrap().unwrap(), "".to_string());
assert!(s.next().is_none());
}
#[test]
fn buf_read_has_data_left() {
let mut buf = Cursor::new(&b"abcd"[..]);
assert!(buf.has_data_left().unwrap());
buf.read_exact(&mut [0; 2]).unwrap();
assert!(buf.has_data_left().unwrap());
buf.read_exact(&mut [0; 2]).unwrap();
assert!(!buf.has_data_left().unwrap());
}
#[test]
fn read_to_end() {
let mut c = Cursor::new(&b""[..]);
let mut v = Vec::new();
assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
assert_eq!(v, []);
let mut c = Cursor::new(&b"1"[..]);
let mut v = Vec::new();
assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
assert_eq!(v, b"1");
let cap = if cfg!(miri) { 1024 } else { 1024 * 1024 };
let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
let mut v = Vec::new();
let (a, b) = data.split_at(data.len() / 2);
assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len());
assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len());
assert_eq!(v, data);
}
#[test]
fn read_to_string() {
let mut c = Cursor::new(&b""[..]);
let mut v = String::new();
assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
assert_eq!(v, "");
let mut c = Cursor::new(&b"1"[..]);
let mut v = String::new();
assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
assert_eq!(v, "1");
let mut c = Cursor::new(&b"\xff"[..]);
let mut v = String::new();
assert!(c.read_to_string(&mut v).is_err());
}
#[test]
fn read_exact() {
let mut buf = [0; 4];
let mut c = Cursor::new(&b""[..]);
assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..]));
c.read_exact(&mut buf).unwrap();
assert_eq!(&buf, b"1234");
c.read_exact(&mut buf).unwrap();
assert_eq!(&buf, b"5678");
assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
}
#[test]
fn read_exact_slice() {
let mut buf = [0; 4];
let mut c = &b""[..];
assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
let mut c = &b"123"[..];
assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
// make sure the optimized (early returning) method is being used
assert_eq!(&buf, &[0; 4]);
let mut c = &b"1234"[..];
c.read_exact(&mut buf).unwrap();
assert_eq!(&buf, b"1234");
let mut c = &b"56789"[..];
c.read_exact(&mut buf).unwrap();
assert_eq!(&buf, b"5678");
assert_eq!(c, b"9");
}
#[test]
fn read_buf_exact() {
let buf: &mut [_] = &mut [0; 4];
let mut buf: BorrowedBuf<'_> = buf.into();
let mut c = Cursor::new(&b""[..]);
assert_eq!(c.read_buf_exact(buf.unfilled()).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
let mut c = Cursor::new(&b"123456789"[..]);
c.read_buf_exact(buf.unfilled()).unwrap();
assert_eq!(buf.filled(), b"1234");
buf.clear();
c.read_buf_exact(buf.unfilled()).unwrap();
assert_eq!(buf.filled(), b"5678");
buf.clear();
assert_eq!(c.read_buf_exact(buf.unfilled()).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
}
#[test]
#[should_panic]
fn borrowed_cursor_advance_overflow() {
let mut buf = [0; 512];
let mut buf = BorrowedBuf::from(&mut buf[..]);
buf.unfilled().advance(1);
buf.unfilled().advance(usize::MAX);
}
#[test]
fn take_eof() {
struct R;
impl Read for R {
fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
Err(io::const_error!(io::ErrorKind::Other, ""))
}
}
impl BufRead for R {
fn fill_buf(&mut self) -> io::Result<&[u8]> {
Err(io::const_error!(io::ErrorKind::Other, ""))
}
fn consume(&mut self, _amt: usize) {}
}
let mut buf = [0; 1];
assert_eq!(0, R.take(0).read(&mut buf).unwrap());
assert_eq!(b"", R.take(0).fill_buf().unwrap());
}
fn cmp_bufread<Br1: BufRead, Br2: BufRead>(mut br1: Br1, mut br2: Br2, exp: &[u8]) {
let mut cat = Vec::new();
loop {
let consume = {
let buf1 = br1.fill_buf().unwrap();
let buf2 = br2.fill_buf().unwrap();
let minlen = if buf1.len() < buf2.len() { buf1.len() } else { buf2.len() };
assert_eq!(buf1[..minlen], buf2[..minlen]);
cat.extend_from_slice(&buf1[..minlen]);
minlen
};
if consume == 0 {
break;
}
br1.consume(consume);
br2.consume(consume);
}
assert_eq!(br1.fill_buf().unwrap().len(), 0);
assert_eq!(br2.fill_buf().unwrap().len(), 0);
assert_eq!(&cat[..], &exp[..])
}
#[test]
fn chain_bufread() {
let testdata = b"ABCDEFGHIJKL";
let chain1 =
(&testdata[..3]).chain(&testdata[3..6]).chain(&testdata[6..9]).chain(&testdata[9..]);
let chain2 = (&testdata[..4]).chain(&testdata[4..8]).chain(&testdata[8..]);
cmp_bufread(chain1, chain2, &testdata[..]);
}
#[test]
fn chain_splitted_char() {
let chain = b"\xc3".chain(b"\xa9".as_slice());
assert_eq!(crate::io::read_to_string(chain).unwrap(), "é");
let mut chain = b"\xc3".chain(b"\xa9\n".as_slice());
let mut buf = String::new();
assert_eq!(chain.read_line(&mut buf).unwrap(), 3);
assert_eq!(buf, "é\n");
}
#[test]
fn bufreader_size_hint() {
let testdata = b"ABCDEFGHIJKL";
let mut buf_reader = BufReader::new(&testdata[..]);
assert_eq!(buf_reader.buffer().len(), 0);
let buffer_length = testdata.len();
buf_reader.fill_buf().unwrap();
// Check that size hint matches buffer contents
let mut buffered_bytes = buf_reader.bytes();
let (lower_bound, _upper_bound) = buffered_bytes.size_hint();
assert_eq!(lower_bound, buffer_length);
// Check that size hint matches buffer contents after advancing
buffered_bytes.next().unwrap().unwrap();
let (lower_bound, _upper_bound) = buffered_bytes.size_hint();
assert_eq!(lower_bound, buffer_length - 1);
}
#[test]
fn empty_size_hint() {
let size_hint = io::empty().bytes().size_hint();
assert_eq!(size_hint, (0, Some(0)));
}
#[test]
fn slice_size_hint() {
let size_hint = (&[1, 2, 3]).bytes().size_hint();
assert_eq!(size_hint, (3, Some(3)));
}
#[test]
fn take_size_hint() {
let size_hint = (&[1, 2, 3]).take(2).bytes().size_hint();
assert_eq!(size_hint, (2, Some(2)));
let size_hint = (&[1, 2, 3]).take(4).bytes().size_hint();
assert_eq!(size_hint, (3, Some(3)));
let size_hint = io::repeat(0).take(3).bytes().size_hint();
assert_eq!(size_hint, (3, Some(3)));
}
#[test]
fn chain_empty_size_hint() {
let chain = io::empty().chain(io::empty());
let size_hint = chain.bytes().size_hint();
assert_eq!(size_hint, (0, Some(0)));
}
#[test]
fn chain_size_hint() {
let testdata = b"ABCDEFGHIJKL";
let mut buf_reader_1 = BufReader::new(&testdata[..6]);
let mut buf_reader_2 = BufReader::new(&testdata[6..]);
buf_reader_1.fill_buf().unwrap();
buf_reader_2.fill_buf().unwrap();
let chain = buf_reader_1.chain(buf_reader_2);
let size_hint = chain.bytes().size_hint();
assert_eq!(size_hint, (testdata.len(), Some(testdata.len())));
}
#[test]
fn chain_zero_length_read_is_not_eof() {
let a = b"A";
let b = b"B";
let mut s = String::new();
let mut chain = (&a[..]).chain(&b[..]);
chain.read(&mut []).unwrap();
chain.read_to_string(&mut s).unwrap();
assert_eq!("AB", s);
}
#[bench]
#[cfg_attr(miri, ignore)] // Miri isn't fast...
fn bench_read_to_end(b: &mut test::Bencher) {
b.iter(|| {
let mut lr = repeat(1).take(10000000);
let mut vec = Vec::with_capacity(1024);
super::default_read_to_end(&mut lr, &mut vec, None)
});
}
#[test]
fn seek_len() -> io::Result<()> {
let mut c = Cursor::new(vec![0; 15]);
assert_eq!(c.stream_len()?, 15);
c.seek(SeekFrom::End(0))?;
let old_pos = c.stream_position()?;
assert_eq!(c.stream_len()?, 15);
assert_eq!(c.stream_position()?, old_pos);
c.seek(SeekFrom::Start(7))?;
c.seek(SeekFrom::Current(2))?;
let old_pos = c.stream_position()?;
assert_eq!(c.stream_len()?, 15);
assert_eq!(c.stream_position()?, old_pos);
Ok(())
}
#[test]
fn seek_position() -> io::Result<()> {
// All `asserts` are duplicated here to make sure the method does not
// change anything about the seek state.
let mut c = Cursor::new(vec![0; 15]);
assert_eq!(c.stream_position()?, 0);
assert_eq!(c.stream_position()?, 0);
c.seek(SeekFrom::End(0))?;
assert_eq!(c.stream_position()?, 15);
assert_eq!(c.stream_position()?, 15);
c.seek(SeekFrom::Start(7))?;
c.seek(SeekFrom::Current(2))?;
assert_eq!(c.stream_position()?, 9);
assert_eq!(c.stream_position()?, 9);
c.seek(SeekFrom::End(-3))?;
c.seek(SeekFrom::Current(1))?;
c.seek(SeekFrom::Current(-5))?;
assert_eq!(c.stream_position()?, 8);
assert_eq!(c.stream_position()?, 8);
c.rewind()?;
assert_eq!(c.stream_position()?, 0);
assert_eq!(c.stream_position()?, 0);
Ok(())
}
#[test]
fn take_seek() -> io::Result<()> {
let mut buf = Cursor::new(b"0123456789");
buf.set_position(2);
let mut take = buf.by_ref().take(4);
let mut buf1 = [0u8; 1];
let mut buf2 = [0u8; 2];
assert_eq!(take.position(), 0);
assert_eq!(take.seek(SeekFrom::Start(0))?, 0);
take.read_exact(&mut buf2)?;
assert_eq!(buf2, [b'2', b'3']);
assert_eq!(take.seek(SeekFrom::Start(1))?, 1);
take.read_exact(&mut buf2)?;
assert_eq!(buf2, [b'3', b'4']);
assert_eq!(take.seek(SeekFrom::Start(2))?, 2);
take.read_exact(&mut buf2)?;
assert_eq!(buf2, [b'4', b'5']);
assert_eq!(take.seek(SeekFrom::Start(3))?, 3);
take.read_exact(&mut buf1)?;
assert_eq!(buf1, [b'5']);
assert_eq!(take.seek(SeekFrom::Start(4))?, 4);
assert_eq!(take.read(&mut buf1)?, 0);
assert_eq!(take.seek(SeekFrom::End(0))?, 4);
assert_eq!(take.seek(SeekFrom::End(-1))?, 3);
take.read_exact(&mut buf1)?;
assert_eq!(buf1, [b'5']);
assert_eq!(take.seek(SeekFrom::End(-2))?, 2);
take.read_exact(&mut buf2)?;
assert_eq!(buf2, [b'4', b'5']);
assert_eq!(take.seek(SeekFrom::End(-3))?, 1);
take.read_exact(&mut buf2)?;
assert_eq!(buf2, [b'3', b'4']);
assert_eq!(take.seek(SeekFrom::End(-4))?, 0);
take.read_exact(&mut buf2)?;
assert_eq!(buf2, [b'2', b'3']);
assert_eq!(take.seek(SeekFrom::Current(0))?, 2);
take.read_exact(&mut buf2)?;
assert_eq!(buf2, [b'4', b'5']);
assert_eq!(take.seek(SeekFrom::Current(-3))?, 1);
take.read_exact(&mut buf2)?;
assert_eq!(buf2, [b'3', b'4']);
assert_eq!(take.seek(SeekFrom::Current(-1))?, 2);
take.read_exact(&mut buf2)?;
assert_eq!(buf2, [b'4', b'5']);
assert_eq!(take.seek(SeekFrom::Current(-4))?, 0);
take.read_exact(&mut buf2)?;
assert_eq!(buf2, [b'2', b'3']);
assert_eq!(take.seek(SeekFrom::Current(2))?, 4);
assert_eq!(take.read(&mut buf1)?, 0);
Ok(())
}
#[test]
fn take_seek_error() {
let buf = Cursor::new(b"0123456789");
let mut take = buf.take(2);
assert!(take.seek(SeekFrom::Start(3)).is_err());
assert!(take.seek(SeekFrom::End(1)).is_err());
assert!(take.seek(SeekFrom::End(-3)).is_err());
assert!(take.seek(SeekFrom::Current(-1)).is_err());
assert!(take.seek(SeekFrom::Current(3)).is_err());
}
struct ExampleHugeRangeOfZeroes {
position: u64,
}
impl Read for ExampleHugeRangeOfZeroes {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
let max = buf.len().min(usize::MAX);
for i in 0..max {
if self.position == u64::MAX {
return Ok(i);
}
self.position += 1;
buf[i] = 0;
}
Ok(max)
}
}
impl Seek for ExampleHugeRangeOfZeroes {
fn seek(&mut self, pos: io::SeekFrom) -> io::Result<u64> {
match pos {
io::SeekFrom::Start(i) => self.position = i,
io::SeekFrom::End(i) if i >= 0 => self.position = u64::MAX,
io::SeekFrom::End(i) => self.position = self.position - i.unsigned_abs(),
io::SeekFrom::Current(i) => {
self.position = if i >= 0 {
self.position.saturating_add(i.unsigned_abs())
} else {
self.position.saturating_sub(i.unsigned_abs())
};
}
}
Ok(self.position)
}
}
#[test]
fn take_seek_big_offsets() -> io::Result<()> {
let inner = ExampleHugeRangeOfZeroes { position: 1 };
let mut take = inner.take(u64::MAX - 2);
assert_eq!(take.seek(io::SeekFrom::Start(u64::MAX - 2))?, u64::MAX - 2);
assert_eq!(take.inner.position, u64::MAX - 1);
assert_eq!(take.seek(io::SeekFrom::Start(0))?, 0);
assert_eq!(take.inner.position, 1);
assert_eq!(take.seek(io::SeekFrom::End(-1))?, u64::MAX - 3);
assert_eq!(take.inner.position, u64::MAX - 2);
Ok(())
}
// A simple example reader which uses the default implementation of
// read_to_end.
struct ExampleSliceReader<'a> {
slice: &'a [u8],
}
impl<'a> Read for ExampleSliceReader<'a> {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
let len = cmp::min(self.slice.len(), buf.len());
buf[..len].copy_from_slice(&self.slice[..len]);
self.slice = &self.slice[len..];
Ok(len)
}
}
#[test]
fn test_read_to_end_capacity() -> io::Result<()> {
let input = &b"foo"[..];
// read_to_end() takes care not to over-allocate when a buffer is the
// exact size needed.
let mut vec1 = Vec::with_capacity(input.len());
ExampleSliceReader { slice: input }.read_to_end(&mut vec1)?;
assert_eq!(vec1.len(), input.len());
assert_eq!(vec1.capacity(), input.len(), "did not allocate more");
Ok(())
}
#[test]
fn io_slice_mut_advance_slices() {
let mut buf1 = [1; 8];
let mut buf2 = [2; 16];
let mut buf3 = [3; 8];
let mut bufs = &mut [
IoSliceMut::new(&mut buf1),
IoSliceMut::new(&mut buf2),
IoSliceMut::new(&mut buf3),
][..];
// Only in a single buffer..
IoSliceMut::advance_slices(&mut bufs, 1);
assert_eq!(bufs[0].deref(), [1; 7].as_ref());
assert_eq!(bufs[1].deref(), [2; 16].as_ref());
assert_eq!(bufs[2].deref(), [3; 8].as_ref());
// Removing a buffer, leaving others as is.
IoSliceMut::advance_slices(&mut bufs, 7);
assert_eq!(bufs[0].deref(), [2; 16].as_ref());
assert_eq!(bufs[1].deref(), [3; 8].as_ref());
// Removing a buffer and removing from the next buffer.
IoSliceMut::advance_slices(&mut bufs, 18);
assert_eq!(bufs[0].deref(), [3; 6].as_ref());
}
#[test]
#[should_panic]
fn io_slice_mut_advance_slices_empty_slice() {
let mut empty_bufs = &mut [][..];
IoSliceMut::advance_slices(&mut empty_bufs, 1);
}
#[test]
#[should_panic]
fn io_slice_mut_advance_slices_beyond_total_length() {
let mut buf1 = [1; 8];
let mut bufs = &mut [IoSliceMut::new(&mut buf1)][..];
IoSliceMut::advance_slices(&mut bufs, 9);
assert!(bufs.is_empty());
}
#[test]
fn io_slice_advance_slices() {
let buf1 = [1; 8];
let buf2 = [2; 16];
let buf3 = [3; 8];
let mut bufs = &mut [IoSlice::new(&buf1), IoSlice::new(&buf2), IoSlice::new(&buf3)][..];
// Only in a single buffer..
IoSlice::advance_slices(&mut bufs, 1);
assert_eq!(bufs[0].deref(), [1; 7].as_ref());
assert_eq!(bufs[1].deref(), [2; 16].as_ref());
assert_eq!(bufs[2].deref(), [3; 8].as_ref());
// Removing a buffer, leaving others as is.
IoSlice::advance_slices(&mut bufs, 7);
assert_eq!(bufs[0].deref(), [2; 16].as_ref());
assert_eq!(bufs[1].deref(), [3; 8].as_ref());
// Removing a buffer and removing from the next buffer.
IoSlice::advance_slices(&mut bufs, 18);
assert_eq!(bufs[0].deref(), [3; 6].as_ref());
}
#[test]
#[should_panic]
fn io_slice_advance_slices_empty_slice() {
let mut empty_bufs = &mut [][..];
IoSlice::advance_slices(&mut empty_bufs, 1);
}
#[test]
#[should_panic]
fn io_slice_advance_slices_beyond_total_length() {
let buf1 = [1; 8];
let mut bufs = &mut [IoSlice::new(&buf1)][..];
IoSlice::advance_slices(&mut bufs, 9);
assert!(bufs.is_empty());
}
#[test]
fn io_slice_as_slice() {
let buf = [1; 8];
let slice = IoSlice::new(&buf).as_slice();
assert_eq!(slice, buf);
}
#[test]
fn io_slice_into_slice() {
let mut buf = [1; 8];
let slice = IoSliceMut::new(&mut buf).into_slice();
assert_eq!(slice, [1; 8]);
}
/// Creates a new writer that reads from at most `n_bufs` and reads
/// `per_call` bytes (in total) per call to write.
fn test_writer(n_bufs: usize, per_call: usize) -> TestWriter {
TestWriter { n_bufs, per_call, written: Vec::new() }
}
struct TestWriter {
n_bufs: usize,
per_call: usize,
written: Vec<u8>,
}
impl Write for TestWriter {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
self.write_vectored(&[IoSlice::new(buf)])
}
fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
let mut left = self.per_call;
let mut written = 0;
for buf in bufs.iter().take(self.n_bufs) {
let n = min(left, buf.len());
self.written.extend_from_slice(&buf[0..n]);
left -= n;
written += n;
}
Ok(written)
}
fn flush(&mut self) -> io::Result<()> {
Ok(())
}
}
#[test]
fn test_writer_read_from_one_buf() {
let mut writer = test_writer(1, 2);
assert_eq!(writer.write(&[]).unwrap(), 0);
assert_eq!(writer.write_vectored(&[]).unwrap(), 0);
// Read at most 2 bytes.
assert_eq!(writer.write(&[1, 1, 1]).unwrap(), 2);
let bufs = &[IoSlice::new(&[2, 2, 2])];
assert_eq!(writer.write_vectored(bufs).unwrap(), 2);
// Only read from first buf.
let bufs = &[IoSlice::new(&[3]), IoSlice::new(&[4, 4])];
assert_eq!(writer.write_vectored(bufs).unwrap(), 1);
assert_eq!(writer.written, &[1, 1, 2, 2, 3]);
}
#[test]
fn test_writer_read_from_multiple_bufs() {
let mut writer = test_writer(3, 3);
// Read at most 3 bytes from two buffers.
let bufs = &[IoSlice::new(&[1]), IoSlice::new(&[2, 2, 2])];
assert_eq!(writer.write_vectored(bufs).unwrap(), 3);
// Read at most 3 bytes from three buffers.
let bufs = &[IoSlice::new(&[3]), IoSlice::new(&[4]), IoSlice::new(&[5, 5])];
assert_eq!(writer.write_vectored(bufs).unwrap(), 3);
assert_eq!(writer.written, &[1, 2, 2, 3, 4, 5]);
}
#[test]
fn test_write_all_vectored() {
#[rustfmt::skip] // Becomes unreadable otherwise.
let tests: Vec<(_, &'static [u8])> = vec![
(vec![], &[]),
(vec![IoSlice::new(&[]), IoSlice::new(&[])], &[]),
(vec![IoSlice::new(&[1])], &[1]),
(vec![IoSlice::new(&[1, 2])], &[1, 2]),
(vec![IoSlice::new(&[1, 2, 3])], &[1, 2, 3]),
(vec![IoSlice::new(&[1, 2, 3, 4])], &[1, 2, 3, 4]),
(vec![IoSlice::new(&[1, 2, 3, 4, 5])], &[1, 2, 3, 4, 5]),
(vec![IoSlice::new(&[1]), IoSlice::new(&[2])], &[1, 2]),
(vec![IoSlice::new(&[1]), IoSlice::new(&[2, 2])], &[1, 2, 2]),
(vec![IoSlice::new(&[1, 1]), IoSlice::new(&[2, 2])], &[1, 1, 2, 2]),
(vec![IoSlice::new(&[1, 1]), IoSlice::new(&[2, 2, 2])], &[1, 1, 2, 2, 2]),
(vec![IoSlice::new(&[1, 1]), IoSlice::new(&[2, 2, 2])], &[1, 1, 2, 2, 2]),
(vec![IoSlice::new(&[1, 1, 1]), IoSlice::new(&[2, 2, 2])], &[1, 1, 1, 2, 2, 2]),
(vec![IoSlice::new(&[1, 1, 1]), IoSlice::new(&[2, 2, 2, 2])], &[1, 1, 1, 2, 2, 2, 2]),
(vec![IoSlice::new(&[1, 1, 1, 1]), IoSlice::new(&[2, 2, 2, 2])], &[1, 1, 1, 1, 2, 2, 2, 2]),
(vec![IoSlice::new(&[1]), IoSlice::new(&[2]), IoSlice::new(&[3])], &[1, 2, 3]),
(vec![IoSlice::new(&[1, 1]), IoSlice::new(&[2, 2]), IoSlice::new(&[3, 3])], &[1, 1, 2, 2, 3, 3]),
(vec![IoSlice::new(&[1]), IoSlice::new(&[2, 2]), IoSlice::new(&[3, 3, 3])], &[1, 2, 2, 3, 3, 3]),
(vec![IoSlice::new(&[1, 1, 1]), IoSlice::new(&[2, 2, 2]), IoSlice::new(&[3, 3, 3])], &[1, 1, 1, 2, 2, 2, 3, 3, 3]),
];
let writer_configs = &[(1, 1), (1, 2), (1, 3), (2, 2), (2, 3), (3, 3)];
for (n_bufs, per_call) in writer_configs.iter().copied() {
for (mut input, wanted) in tests.clone().into_iter() {
let mut writer = test_writer(n_bufs, per_call);
assert!(writer.write_all_vectored(&mut *input).is_ok());
assert_eq!(&*writer.written, &*wanted);
}
}
}
// Issue 94981
#[test]
#[should_panic = "number of read bytes exceeds limit"]
fn test_take_wrong_length() {
struct LieAboutSize(bool);
impl Read for LieAboutSize {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
// Lie about the read size at first time of read.
if core::mem::take(&mut self.0) { Ok(buf.len() + 1) } else { Ok(buf.len()) }
}
}
let mut buffer = vec![0; 4];
let mut reader = LieAboutSize(true).take(4);
// Primed the `Limit` by lying about the read size.
let _ = reader.read(&mut buffer[..]);
}
#[test]
fn slice_read_exact_eof() {
let slice = &b"123456"[..];
let mut r = slice;
assert!(r.read_exact(&mut [0; 10]).is_err());
assert!(r.is_empty());
let mut r = slice;
let buf = &mut [0; 10];
let mut buf = BorrowedBuf::from(buf.as_mut_slice());
assert!(r.read_buf_exact(buf.unfilled()).is_err());
assert!(r.is_empty());
assert_eq!(buf.filled(), b"123456");
}
#[test]
fn cursor_read_exact_eof() {
let slice = Cursor::new(b"123456");
let mut r = slice.clone();
assert!(r.read_exact(&mut [0; 10]).is_err());
assert!(Cursor::split(&r).1.is_empty());
let mut r = slice;
let buf = &mut [0; 10];
let mut buf = BorrowedBuf::from(buf.as_mut_slice());
assert!(r.read_buf_exact(buf.unfilled()).is_err());
assert!(Cursor::split(&r).1.is_empty());
assert_eq!(buf.filled(), b"123456");
}
#[bench]
fn bench_take_read(b: &mut test::Bencher) {
b.iter(|| {
let mut buf = [0; 64];
[255; 128].take(64).read(&mut buf).unwrap();
});
}
#[bench]
fn bench_take_read_buf(b: &mut test::Bencher) {
b.iter(|| {
let buf: &mut [_] = &mut [MaybeUninit::uninit(); 64];
let mut buf: BorrowedBuf<'_> = buf.into();
[255; 128].take(64).read_buf(buf.unfilled()).unwrap();
});
}
// Issue #120603
#[test]
#[should_panic]
fn read_buf_broken_read() {
struct MalformedRead;
impl Read for MalformedRead {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
// broken length calculation
Ok(buf.len() + 1)
}
}
let _ = BufReader::new(MalformedRead).fill_buf();
}
#[test]
fn read_buf_full_read() {
struct FullRead;
impl Read for FullRead {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
Ok(buf.len())
}
}
assert_eq!(BufReader::new(FullRead).fill_buf().unwrap().len(), DEFAULT_BUF_SIZE);
}
struct DataAndErrorReader(&'static [u8]);
impl Read for DataAndErrorReader {
fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> {
panic!("We want tests to use `read_buf`")
}
fn read_buf(&mut self, buf: io::BorrowedCursor<'_>) -> io::Result<()> {
self.0.read_buf(buf).unwrap();
Err(io::Error::other("error"))
}
}
#[test]
fn read_buf_data_and_error_take() {
let mut buf = [0; 64];
let mut buf = io::BorrowedBuf::from(buf.as_mut_slice());
let mut r = DataAndErrorReader(&[4, 5, 6]).take(1);
assert!(r.read_buf(buf.unfilled()).is_err());
assert_eq!(buf.filled(), &[4]);
assert!(r.read_buf(buf.unfilled()).is_ok());
assert_eq!(buf.filled(), &[4]);
assert_eq!(r.get_ref().0, &[5, 6]);
}
#[test]
fn read_buf_data_and_error_buf() {
let mut r = BufReader::new(DataAndErrorReader(&[4, 5, 6]));
assert!(r.fill_buf().is_err());
assert_eq!(r.fill_buf().unwrap(), &[4, 5, 6]);
}
#[test]
fn read_buf_data_and_error_read_to_end() {
let mut r = DataAndErrorReader(&[4, 5, 6]);
let mut v = Vec::with_capacity(200);
assert!(r.read_to_end(&mut v).is_err());
assert_eq!(v, &[4, 5, 6]);
}
#[test]
fn read_to_end_error() {
struct ErrorReader;
impl Read for ErrorReader {
fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> {
Err(io::Error::other("error"))
}
}
let mut r = [4, 5, 6].chain(ErrorReader);
let mut v = Vec::with_capacity(200);
assert!(r.read_to_end(&mut v).is_err());
assert_eq!(v, &[4, 5, 6]);
}
#[test]
fn try_oom_error() {
use alloc::alloc::Layout;
use alloc::collections::{TryReserveError, TryReserveErrorKind};
// We simulate a `Vec::try_reserve` error rather than attempting a huge size for real. This way
// we're not subject to the whims of optimization that might skip the actual allocation, and it
// also works for 32-bit targets and miri that might not OOM at all.
let layout = Layout::new::<u8>();
let kind = TryReserveErrorKind::AllocError { layout, non_exhaustive: () };
let reserve_err = TryReserveError::from(kind);
let io_err = io::Error::from(reserve_err);
assert_eq!(io::ErrorKind::OutOfMemory, io_err.kind());
}

2
crates/io/src/io/util.rs → crates/std/src/io/util.rs
View File

@@ -1,5 +1,7 @@
#![allow(missing_copy_implementations)]
#[cfg(test)]
mod tests;
use crate::fmt;
use crate::io::{

185
crates/std/src/io/util/tests.rs Normal file
View File

@@ -0,0 +1,185 @@
use crate::fmt;
use crate::io::prelude::*;
use crate::io::{
BorrowedBuf, Empty, ErrorKind, IoSlice, IoSliceMut, Repeat, SeekFrom, Sink, empty, repeat, sink,
};
use crate::mem::MaybeUninit;
struct ErrorDisplay;
impl fmt::Display for ErrorDisplay {
fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
Err(fmt::Error)
}
}
struct PanicDisplay;
impl fmt::Display for PanicDisplay {
fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
panic!()
}
}
#[track_caller]
fn test_sinking<W: Write>(mut w: W) {
assert_eq!(w.write(&[]).unwrap(), 0);
assert_eq!(w.write(&[0]).unwrap(), 1);
assert_eq!(w.write(&[0; 1024]).unwrap(), 1024);
w.write_all(&[]).unwrap();
w.write_all(&[0]).unwrap();
w.write_all(&[0; 1024]).unwrap();
let mut bufs =
[IoSlice::new(&[]), IoSlice::new(&[0]), IoSlice::new(&[0; 1024]), IoSlice::new(&[])];
assert!(w.is_write_vectored());
assert_eq!(w.write_vectored(&[]).unwrap(), 0);
assert_eq!(w.write_vectored(&bufs).unwrap(), 1025);
w.write_all_vectored(&mut []).unwrap();
w.write_all_vectored(&mut bufs).unwrap();
assert!(w.flush().is_ok());
assert_eq!(w.by_ref().write(&[0; 1024]).unwrap(), 1024);
// Ignores fmt arguments
w.write_fmt(format_args!("{}", ErrorDisplay)).unwrap();
w.write_fmt(format_args!("{}", PanicDisplay)).unwrap();
}
#[test]
fn sink_sinks() {
test_sinking(sink());
}
#[test]
fn empty_reads() {
let mut e = empty();
assert_eq!(e.read(&mut []).unwrap(), 0);
assert_eq!(e.read(&mut [0]).unwrap(), 0);
assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0);
assert_eq!(Read::by_ref(&mut e).read(&mut [0; 1024]).unwrap(), 0);
e.read_exact(&mut []).unwrap();
assert_eq!(e.read_exact(&mut [0]).unwrap_err().kind(), ErrorKind::UnexpectedEof);
assert_eq!(e.read_exact(&mut [0; 1024]).unwrap_err().kind(), ErrorKind::UnexpectedEof);
assert!(!e.is_read_vectored());
assert_eq!(e.read_vectored(&mut []).unwrap(), 0);
let (mut buf1, mut buf1024) = ([0], [0; 1024]);
let bufs = &mut [
IoSliceMut::new(&mut []),
IoSliceMut::new(&mut buf1),
IoSliceMut::new(&mut buf1024),
IoSliceMut::new(&mut []),
];
assert_eq!(e.read_vectored(bufs).unwrap(), 0);
let buf: &mut [MaybeUninit<_>] = &mut [];
let mut buf: BorrowedBuf<'_> = buf.into();
e.read_buf(buf.unfilled()).unwrap();
assert_eq!(buf.len(), 0);
assert_eq!(buf.init_len(), 0);
let buf: &mut [_] = &mut [MaybeUninit::uninit()];
let mut buf: BorrowedBuf<'_> = buf.into();
e.read_buf(buf.unfilled()).unwrap();
assert_eq!(buf.len(), 0);
assert_eq!(buf.init_len(), 0);
let buf: &mut [_] = &mut [MaybeUninit::uninit(); 1024];
let mut buf: BorrowedBuf<'_> = buf.into();
e.read_buf(buf.unfilled()).unwrap();
assert_eq!(buf.len(), 0);
assert_eq!(buf.init_len(), 0);
let buf: &mut [_] = &mut [MaybeUninit::uninit(); 1024];
let mut buf: BorrowedBuf<'_> = buf.into();
Read::by_ref(&mut e).read_buf(buf.unfilled()).unwrap();
assert_eq!(buf.len(), 0);
assert_eq!(buf.init_len(), 0);
let buf: &mut [MaybeUninit<_>] = &mut [];
let mut buf: BorrowedBuf<'_> = buf.into();
e.read_buf_exact(buf.unfilled()).unwrap();
assert_eq!(buf.len(), 0);
assert_eq!(buf.init_len(), 0);
let buf: &mut [_] = &mut [MaybeUninit::uninit()];
let mut buf: BorrowedBuf<'_> = buf.into();
assert_eq!(e.read_buf_exact(buf.unfilled()).unwrap_err().kind(), ErrorKind::UnexpectedEof);
assert_eq!(buf.len(), 0);
assert_eq!(buf.init_len(), 0);
let buf: &mut [_] = &mut [MaybeUninit::uninit(); 1024];
let mut buf: BorrowedBuf<'_> = buf.into();
assert_eq!(e.read_buf_exact(buf.unfilled()).unwrap_err().kind(), ErrorKind::UnexpectedEof);
assert_eq!(buf.len(), 0);
assert_eq!(buf.init_len(), 0);
let buf: &mut [_] = &mut [MaybeUninit::uninit(); 1024];
let mut buf: BorrowedBuf<'_> = buf.into();
assert_eq!(
Read::by_ref(&mut e).read_buf_exact(buf.unfilled()).unwrap_err().kind(),
ErrorKind::UnexpectedEof,
);
assert_eq!(buf.len(), 0);
assert_eq!(buf.init_len(), 0);
let mut buf = Vec::new();
assert_eq!(e.read_to_end(&mut buf).unwrap(), 0);
assert_eq!(buf, vec![]);
let mut buf = vec![1, 2, 3];
assert_eq!(e.read_to_end(&mut buf).unwrap(), 0);
assert_eq!(buf, vec![1, 2, 3]);
let mut buf = String::new();
assert_eq!(e.read_to_string(&mut buf).unwrap(), 0);
assert_eq!(buf, "");
let mut buf = "hello".to_owned();
assert_eq!(e.read_to_string(&mut buf).unwrap(), 0);
assert_eq!(buf, "hello");
}
#[test]
fn empty_seeks() {
let mut e = empty();
assert!(matches!(e.seek(SeekFrom::Start(0)), Ok(0)));
assert!(matches!(e.seek(SeekFrom::Start(1)), Ok(0)));
assert!(matches!(e.seek(SeekFrom::Start(u64::MAX)), Ok(0)));
assert!(matches!(e.seek(SeekFrom::End(i64::MIN)), Ok(0)));
assert!(matches!(e.seek(SeekFrom::End(-1)), Ok(0)));
assert!(matches!(e.seek(SeekFrom::End(0)), Ok(0)));
assert!(matches!(e.seek(SeekFrom::End(1)), Ok(0)));
assert!(matches!(e.seek(SeekFrom::End(i64::MAX)), Ok(0)));
assert!(matches!(e.seek(SeekFrom::Current(i64::MIN)), Ok(0)));
assert!(matches!(e.seek(SeekFrom::Current(-1)), Ok(0)));
assert!(matches!(e.seek(SeekFrom::Current(0)), Ok(0)));
assert!(matches!(e.seek(SeekFrom::Current(1)), Ok(0)));
assert!(matches!(e.seek(SeekFrom::Current(i64::MAX)), Ok(0)));
}
#[test]
fn empty_sinks() {
test_sinking(empty());
}
#[test]
fn repeat_repeats() {
let mut r = repeat(4);
let mut b = [0; 1024];
assert_eq!(r.read(&mut b).unwrap(), 1024);
assert!(b.iter().all(|b| *b == 4));
}
#[test]
fn take_some_bytes() {
assert_eq!(repeat(4).take(100).bytes().count(), 100);
assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4);
assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20);
}
#[allow(dead_code)]
fn const_utils() {
const _: Empty = empty();
const _: Repeat = repeat(b'c');
const _: Sink = sink();
}

329
crates/std/src/lib.rs Normal file
View File

@@ -0,0 +1,329 @@
#![unstable(feature = "custom_std", issue = "none")]
#![no_std]
//
// Lints:
#![warn(deprecated_in_future)]
// #![warn(missing_docs)]
// #![warn(missing_debug_implementations)]
#![allow(explicit_outlives_requirements)]
#![allow(unused_lifetimes)]
#![allow(internal_features)]
#![deny(fuzzy_provenance_casts)]
#![deny(unsafe_op_in_unsafe_fn)]
#![allow(rustdoc::redundant_explicit_links)]
#![warn(rustdoc::unescaped_backticks)]
// Ensure that std can be linked against panic_abort despite compiled with `-C panic=unwind`
#![deny(ffi_unwind_calls)]
// std may use features in a platform-specific way
#![allow(unused_features)]
//
// Features:
#![cfg_attr(
test,
feature(internal_output_capture, print_internals, update_panic_count, rt)
)]
#![cfg_attr(
all(target_vendor = "fortanix", target_env = "sgx"),
feature(slice_index_methods, coerce_unsized, sgx_platform)
)]
#![cfg_attr(all(test, target_os = "uefi"), feature(uefi_std))]
#![cfg_attr(target_family = "wasm", feature(stdarch_wasm_atomic_wait))]
#![cfg_attr(target_arch = "wasm64", feature(simd_wasm64))]
//
// Language features:
// tidy-alphabetical-start
#![feature(alloc_error_handler)]
#![feature(allocator_internals)]
#![feature(allow_internal_unsafe)]
#![feature(allow_internal_unstable)]
#![feature(asm_experimental_arch)]
#![feature(autodiff)]
#![feature(cfg_sanitizer_cfi)]
#![feature(cfg_target_thread_local)]
#![feature(cfi_encoding)]
#![feature(const_default)]
#![feature(const_trait_impl)]
#![feature(core_float_math)]
#![feature(decl_macro)]
#![feature(deprecated_suggestion)]
#![feature(doc_cfg)]
#![feature(doc_masked)]
#![feature(doc_notable_trait)]
#![feature(dropck_eyepatch)]
#![feature(f16)]
#![feature(f128)]
#![feature(ffi_const)]
#![feature(formatting_options)]
#![feature(funnel_shifts)]
#![feature(if_let_guard)]
#![feature(intra_doc_pointers)]
#![feature(iter_advance_by)]
#![feature(iter_next_chunk)]
#![feature(lang_items)]
#![feature(link_cfg)]
#![feature(linkage)]
#![feature(macro_metavar_expr_concat)]
#![feature(maybe_uninit_fill)]
#![feature(min_specialization)]
#![feature(must_not_suspend)]
#![feature(needs_panic_runtime)]
#![feature(negative_impls)]
#![feature(never_type)]
#![feature(optimize_attribute)]
#![feature(prelude_import)]
#![feature(rustc_attrs)]
#![feature(rustdoc_internals)]
#![feature(staged_api)]
#![feature(stmt_expr_attributes)]
#![feature(strict_provenance_lints)]
#![feature(thread_local)]
#![feature(try_blocks)]
#![feature(try_trait_v2)]
#![feature(type_alias_impl_trait)]
// tidy-alphabetical-end
//
// Library features (core):
// tidy-alphabetical-start
#![feature(bstr)]
#![feature(bstr_internals)]
#![feature(cast_maybe_uninit)]
#![feature(cfg_select)]
#![feature(char_internals)]
#![feature(clone_to_uninit)]
#![feature(const_convert)]
#![feature(core_intrinsics)]
#![feature(core_io_borrowed_buf)]
#![feature(drop_guard)]
#![feature(duration_constants)]
#![feature(error_generic_member_access)]
#![feature(error_iter)]
#![feature(exact_size_is_empty)]
#![feature(exclusive_wrapper)]
#![feature(extend_one)]
#![feature(float_algebraic)]
// #![feature(float_gamma)]
#![feature(float_minimum_maximum)]
#![feature(fmt_internals)]
#![feature(fn_ptr_trait)]
#![feature(generic_atomic)]
#![feature(hasher_prefixfree_extras)]
#![feature(hashmap_internals)]
#![feature(hint_must_use)]
#![feature(int_from_ascii)]
#![feature(ip)]
#![feature(maybe_uninit_array_assume_init)]
#![feature(panic_can_unwind)]
#![feature(panic_internals)]
#![feature(pin_coerce_unsized_trait)]
#![feature(pointer_is_aligned_to)]
#![feature(portable_simd)]
#![feature(ptr_as_uninit)]
#![feature(ptr_mask)]
#![feature(random)]
#![feature(slice_internals)]
#![feature(slice_ptr_get)]
#![feature(slice_range)]
#![feature(slice_split_once)]
#![feature(std_internals)]
#![feature(str_internals)]
#![feature(sync_unsafe_cell)]
#![feature(temporary_niche_types)]
#![feature(ub_checks)]
#![feature(used_with_arg)]
// tidy-alphabetical-end
//
// Library features (alloc):
// tidy-alphabetical-start
#![feature(alloc_layout_extra)]
#![feature(allocator_api)]
#![feature(clone_from_ref)]
#![feature(get_mut_unchecked)]
#![feature(map_try_insert)]
#![feature(slice_concat_trait)]
#![feature(thin_box)]
#![feature(try_reserve_kind)]
#![feature(try_with_capacity)]
#![feature(unique_rc_arc)]
#![feature(wtf8_internals)]
// tidy-alphabetical-end
//
// Library features (unwind):
// tidy-alphabetical-start
// #![feature(panic_unwind)]
// tidy-alphabetical-end
//
// Library features (std_detect):
// tidy-alphabetical-start
// #![feature(stdarch_internal)]
// tidy-alphabetical-end
//
// Only for re-exporting:
// tidy-alphabetical-start
#![feature(assert_matches)]
#![feature(async_iterator)]
#![feature(c_variadic)]
#![feature(cfg_accessible)]
#![feature(cfg_eval)]
#![feature(concat_bytes)]
#![feature(const_format_args)]
#![feature(custom_test_frameworks)]
#![feature(edition_panic)]
#![feature(format_args_nl)]
#![feature(log_syntax)]
#![feature(test)]
#![feature(trace_macros)]
// tidy-alphabetical-end
//
// Only used in tests/benchmarks:
//
// Only for const-ness:
// tidy-alphabetical-start
#![feature(io_const_error)]
// tidy-alphabetical-end
//
#![feature(c_size_t, unsafe_binders)]
#![allow(clippy::doc_lazy_continuation, clippy::all)]
#![allow(
stable_features,
incomplete_features,
unexpected_cfgs,
unfulfilled_lint_expectations
)]
#![allow(unused)]
#[macro_use]
extern crate alloc as alloc_crate;
pub use core::any;
pub use core::array;
pub use core::async_iter;
pub use core::cell;
pub use core::char;
pub use core::clone;
pub use core::cmp;
pub use core::convert;
pub use core::default;
pub use core::future;
pub use core::hint;
#[allow(deprecated, deprecated_in_future)]
pub use core::i8;
#[allow(deprecated, deprecated_in_future)]
pub use core::i16;
#[allow(deprecated, deprecated_in_future)]
pub use core::i32;
#[allow(deprecated, deprecated_in_future)]
pub use core::i64;
#[allow(deprecated, deprecated_in_future)]
pub use core::i128;
pub use core::intrinsics;
#[allow(deprecated, deprecated_in_future)]
pub use core::isize;
pub use core::iter;
pub use core::marker;
pub use core::mem;
pub use core::ops;
pub use core::option;
pub use core::pin;
pub use core::ptr;
pub use core::range;
pub use core::result;
#[allow(deprecated, deprecated_in_future)]
pub use core::u8;
#[allow(deprecated, deprecated_in_future)]
pub use core::u16;
#[allow(deprecated, deprecated_in_future)]
pub use core::u32;
#[allow(deprecated, deprecated_in_future)]
pub use core::u64;
#[allow(deprecated, deprecated_in_future)]
pub use core::u128;
pub use core::unsafe_binder;
#[allow(deprecated, deprecated_in_future)]
pub use core::usize;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::borrow;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::boxed;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::fmt;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::format;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::rc;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::slice;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::str;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::string;
#[stable(feature = "rust1", since = "1.0.0")]
pub use alloc_crate::vec;
#[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
pub use core::{
assert, cfg, column, compile_error, concat, const_format_args, env, file, format_args,
format_args_nl, include, include_bytes, include_str, line, log_syntax, module_path, option_env,
stringify, trace_macros,
};
#[rustc_std_internal_symbol]
pub unsafe fn __rust_start_panic(_payload: &mut dyn core::panic::PanicPayload) -> u32 {
todo!()
}
pub mod ffi;
pub mod hash;
pub mod io;
// pub mod fs;
pub mod error;
pub mod num;
pub mod path;
pub mod prelude;
pub mod process;
#[macro_use]
pub mod rt;
pub mod alloc;
pub mod bstr;
pub mod collections;
pub mod env;
pub mod panic;
pub mod panicking;
pub mod sync;
pub mod sys;
pub mod thread;
pub mod time;
#[prelude_import]
#[allow(unused_imports)]
pub use prelude::rust_2024::*;
#[allow(unused)]
mod sealed {
/// This trait being unreachable from outside the crate
/// prevents outside implementations of our extension traits.
/// This allows adding more trait methods in the future.
#[unstable(feature = "sealed", issue = "none")]
pub trait Sealed {}
}
pub use shared::fs;
pub use shared::syscall;
#[macro_export]
macro_rules! print {
($($args:expr),*) => {
$crate::syscall::write_string_temp(&format!($($args),*))
};
}
#[macro_export]
macro_rules! println {
() => {
$crate::print!("");
// $crate::print!("\n\r");
};
($($args:expr),*) => {
$crate::print!($($args),*);
// $crate::println!();
};
}

28
crates/std/src/num/mod.rs Normal file
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@@ -0,0 +1,28 @@
//! Additional functionality for numerics.
//!
//! This module provides some extra types that are useful when doing numerical
//! work. See the individual documentation for each piece for more information.
#![stable(feature = "rust1", since = "1.0.0")]
#![allow(missing_docs)]
#[stable(feature = "int_error_matching", since = "1.55.0")]
pub use core::num::IntErrorKind;
#[stable(feature = "generic_nonzero", since = "1.79.0")]
pub use core::num::NonZero;
#[stable(feature = "saturating_int_impl", since = "1.74.0")]
pub use core::num::Saturating;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::num::Wrapping;
#[unstable(
feature = "nonzero_internals",
reason = "implementation detail which may disappear or be replaced at any time",
issue = "none"
)]
pub use core::num::ZeroablePrimitive;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::num::{FpCategory, ParseFloatError, ParseIntError, TryFromIntError};
#[stable(feature = "signed_nonzero", since = "1.34.0")]
pub use core::num::{NonZeroI8, NonZeroI16, NonZeroI32, NonZeroI64, NonZeroI128, NonZeroIsize};
#[stable(feature = "nonzero", since = "1.28.0")]
pub use core::num::{NonZeroU8, NonZeroU16, NonZeroU32, NonZeroU64, NonZeroU128, NonZeroUsize};

534
crates/std/src/panic.rs Normal file
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@@ -0,0 +1,534 @@
//! Panic support in the standard library.
#![stable(feature = "std_panic", since = "1.9.0")]
use crate::any::Any;
use crate::sync::atomic::{Atomic, AtomicU8, Ordering};
use crate::sync::{Condvar, Mutex, RwLock};
use crate::thread::Result;
use crate::{collections, fmt, panicking};
#[stable(feature = "panic_hooks", since = "1.10.0")]
#[deprecated(
since = "1.82.0",
note = "use `PanicHookInfo` instead",
suggestion = "std::panic::PanicHookInfo"
)]
/// A struct providing information about a panic.
///
/// `PanicInfo` has been renamed to [`PanicHookInfo`] to avoid confusion with
/// [`core::panic::PanicInfo`].
pub type PanicInfo<'a> = PanicHookInfo<'a>;
/// A struct providing information about a panic.
///
/// `PanicHookInfo` structure is passed to a panic hook set by the [`set_hook`] function.
///
/// # Examples
///
/// ```should_panic
/// use std::panic;
///
/// panic::set_hook(Box::new(|panic_info| {
/// println!("panic occurred: {panic_info}");
/// }));
///
/// panic!("critical system failure");
/// ```
///
/// [`set_hook`]: ../../std/panic/fn.set_hook.html
#[stable(feature = "panic_hook_info", since = "1.81.0")]
#[derive(Debug)]
pub struct PanicHookInfo<'a> {
payload: &'a (dyn Any + Send),
location: &'a Location<'a>,
can_unwind: bool,
force_no_backtrace: bool,
}
impl<'a> PanicHookInfo<'a> {
#[inline]
pub(crate) fn new(
location: &'a Location<'a>,
payload: &'a (dyn Any + Send),
can_unwind: bool,
force_no_backtrace: bool,
) -> Self {
PanicHookInfo { payload, location, can_unwind, force_no_backtrace }
}
/// Returns the payload associated with the panic.
///
/// This will commonly, but not always, be a `&'static str` or [`String`].
/// If you only care about such payloads, use [`payload_as_str`] instead.
///
/// A invocation of the `panic!()` macro in Rust 2021 or later will always result in a
/// panic payload of type `&'static str` or `String`.
///
/// Only an invocation of [`panic_any`]
/// (or, in Rust 2018 and earlier, `panic!(x)` where `x` is something other than a string)
/// can result in a panic payload other than a `&'static str` or `String`.
///
/// [`String`]: ../../std/string/struct.String.html
/// [`payload_as_str`]: PanicHookInfo::payload_as_str
///
/// # Examples
///
/// ```should_panic
/// use std::panic;
///
/// panic::set_hook(Box::new(|panic_info| {
/// if let Some(s) = panic_info.payload().downcast_ref::<&str>() {
/// println!("panic occurred: {s:?}");
/// } else if let Some(s) = panic_info.payload().downcast_ref::<String>() {
/// println!("panic occurred: {s:?}");
/// } else {
/// println!("panic occurred");
/// }
/// }));
///
/// panic!("Normal panic");
/// ```
#[must_use]
#[inline]
#[stable(feature = "panic_hooks", since = "1.10.0")]
pub fn payload(&self) -> &(dyn Any + Send) {
self.payload
}
/// Returns the payload associated with the panic, if it is a string.
///
/// This returns the payload if it is of type `&'static str` or `String`.
///
/// A invocation of the `panic!()` macro in Rust 2021 or later will always result in a
/// panic payload where `payload_as_str` returns `Some`.
///
/// Only an invocation of [`panic_any`]
/// (or, in Rust 2018 and earlier, `panic!(x)` where `x` is something other than a string)
/// can result in a panic payload where `payload_as_str` returns `None`.
///
/// # Example
///
/// ```should_panic
/// std::panic::set_hook(Box::new(|panic_info| {
/// if let Some(s) = panic_info.payload_as_str() {
/// println!("panic occurred: {s:?}");
/// } else {
/// println!("panic occurred");
/// }
/// }));
///
/// panic!("Normal panic");
/// ```
#[must_use]
#[inline]
#[stable(feature = "panic_payload_as_str", since = "1.91.0")]
pub fn payload_as_str(&self) -> Option<&str> {
if let Some(s) = self.payload.downcast_ref::<&str>() {
Some(s)
} else if let Some(s) = self.payload.downcast_ref::<String>() {
Some(s)
} else {
None
}
}
/// Returns information about the location from which the panic originated,
/// if available.
///
/// This method will currently always return [`Some`], but this may change
/// in future versions.
///
/// # Examples
///
/// ```should_panic
/// use std::panic;
///
/// panic::set_hook(Box::new(|panic_info| {
/// if let Some(location) = panic_info.location() {
/// println!("panic occurred in file '{}' at line {}",
/// location.file(),
/// location.line(),
/// );
/// } else {
/// println!("panic occurred but can't get location information...");
/// }
/// }));
///
/// panic!("Normal panic");
/// ```
#[must_use]
#[inline]
#[stable(feature = "panic_hooks", since = "1.10.0")]
pub fn location(&self) -> Option<&Location<'_>> {
// NOTE: If this is changed to sometimes return None,
// deal with that case in std::panicking::default_hook and core::panicking::panic_fmt.
Some(&self.location)
}
/// Returns whether the panic handler is allowed to unwind the stack from
/// the point where the panic occurred.
///
/// This is true for most kinds of panics with the exception of panics
/// caused by trying to unwind out of a `Drop` implementation or a function
/// whose ABI does not support unwinding.
///
/// It is safe for a panic handler to unwind even when this function returns
/// false, however this will simply cause the panic handler to be called
/// again.
#[must_use]
#[inline]
#[unstable(feature = "panic_can_unwind", issue = "92988")]
pub fn can_unwind(&self) -> bool {
self.can_unwind
}
#[unstable(
feature = "panic_internals",
reason = "internal details of the implementation of the `panic!` and related macros",
issue = "none"
)]
#[doc(hidden)]
#[inline]
pub fn force_no_backtrace(&self) -> bool {
self.force_no_backtrace
}
}
#[stable(feature = "panic_hook_display", since = "1.26.0")]
impl fmt::Display for PanicHookInfo<'_> {
fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
formatter.write_str("panicked at ")?;
self.location.fmt(formatter)?;
if let Some(payload) = self.payload_as_str() {
formatter.write_str(":\n")?;
formatter.write_str(payload)?;
}
Ok(())
}
}
#[doc(hidden)]
#[unstable(feature = "edition_panic", issue = "none", reason = "use panic!() instead")]
#[allow_internal_unstable(libstd_sys_internals, const_format_args, panic_internals, rt)]
#[cfg_attr(not(test), rustc_diagnostic_item = "std_panic_2015_macro")]
#[rustc_macro_transparency = "semiopaque"]
pub macro panic_2015 {
() => ({
$crate::rt::begin_panic("explicit panic")
}),
($msg:expr $(,)?) => ({
$crate::rt::begin_panic($msg);
}),
// Special-case the single-argument case for const_panic.
("{}", $arg:expr $(,)?) => ({
$crate::rt::panic_display(&$arg);
}),
($fmt:expr, $($arg:tt)+) => ({
// Semicolon to prevent temporaries inside the formatting machinery from
// being considered alive in the caller after the panic_fmt call.
$crate::rt::panic_fmt($crate::const_format_args!($fmt, $($arg)+));
}),
}
#[stable(feature = "panic_hooks", since = "1.10.0")]
pub use core::panic::Location;
#[doc(hidden)]
#[unstable(feature = "edition_panic", issue = "none", reason = "use panic!() instead")]
pub use core::panic::panic_2021;
#[stable(feature = "catch_unwind", since = "1.9.0")]
pub use core::panic::{AssertUnwindSafe, RefUnwindSafe, UnwindSafe};
#[unstable(feature = "panic_update_hook", issue = "92649")]
pub use crate::panicking::update_hook;
#[stable(feature = "panic_hooks", since = "1.10.0")]
pub use crate::panicking::{set_hook, take_hook};
/// Panics the current thread with the given message as the panic payload.
///
/// The message can be of any (`Any + Send`) type, not just strings.
///
/// The message is wrapped in a `Box<'static + Any + Send>`, which can be
/// accessed later using [`PanicHookInfo::payload`].
///
/// See the [`panic!`] macro for more information about panicking.
#[stable(feature = "panic_any", since = "1.51.0")]
#[inline]
#[track_caller]
#[cfg_attr(not(test), rustc_diagnostic_item = "panic_any")]
pub fn panic_any<M: 'static + Any + Send>(msg: M) -> ! {
crate::panicking::begin_panic(msg);
}
#[stable(feature = "catch_unwind", since = "1.9.0")]
impl<T: ?Sized> UnwindSafe for Mutex<T> {}
#[stable(feature = "catch_unwind", since = "1.9.0")]
impl<T: ?Sized> UnwindSafe for RwLock<T> {}
#[stable(feature = "catch_unwind", since = "1.9.0")]
impl UnwindSafe for Condvar {}
#[stable(feature = "unwind_safe_lock_refs", since = "1.12.0")]
impl<T: ?Sized> RefUnwindSafe for Mutex<T> {}
#[stable(feature = "unwind_safe_lock_refs", since = "1.12.0")]
impl<T: ?Sized> RefUnwindSafe for RwLock<T> {}
#[stable(feature = "unwind_safe_lock_refs", since = "1.12.0")]
impl RefUnwindSafe for Condvar {}
// https://github.com/rust-lang/rust/issues/62301
#[stable(feature = "hashbrown", since = "1.36.0")]
impl<K, V, S> UnwindSafe for collections::HashMap<K, V, S>
where
K: UnwindSafe,
V: UnwindSafe,
S: UnwindSafe,
{
}
#[unstable(feature = "abort_unwind", issue = "130338")]
pub use core::panic::abort_unwind;
/// Invokes a closure, capturing the cause of an unwinding panic if one occurs.
///
/// This function will return `Ok` with the closure's result if the closure does
/// not panic, and will return `Err(cause)` if the closure panics. The `cause`
/// returned is the object with which panic was originally invoked.
///
/// Rust functions that are expected to be called from foreign code that does
/// not support unwinding (such as C compiled with `-fno-exceptions`) should be
/// defined using `extern "C"`, which ensures that if the Rust code panics, it
/// is automatically caught and the process is aborted. If this is the desired
/// behavior, it is not necessary to use `catch_unwind` explicitly. This
/// function should instead be used when more graceful error-handling is needed.
///
/// It is **not** recommended to use this function for a general try/catch
/// mechanism. The [`Result`] type is more appropriate to use for functions that
/// can fail on a regular basis. Additionally, this function is not guaranteed
/// to catch all panics, see the "Notes" section below.
///
/// The closure provided is required to adhere to the [`UnwindSafe`] trait to
/// ensure that all captured variables are safe to cross this boundary. The
/// purpose of this bound is to encode the concept of [exception safety][rfc] in
/// the type system. Most usage of this function should not need to worry about
/// this bound as programs are naturally unwind safe without `unsafe` code. If
/// it becomes a problem the [`AssertUnwindSafe`] wrapper struct can be used to
/// quickly assert that the usage here is indeed unwind safe.
///
/// [rfc]: https://github.com/rust-lang/rfcs/blob/master/text/1236-stabilize-catch-panic.md
///
/// # Notes
///
/// This function **might not catch all Rust panics**. A Rust panic is not
/// always implemented via unwinding, but can be implemented by aborting the
/// process as well. This function *only* catches unwinding panics, not those
/// that abort the process.
///
/// If a custom panic hook has been set, it will be invoked before the panic is
/// caught, before unwinding.
///
/// Although unwinding into Rust code with a foreign exception (e.g. an
/// exception thrown from C++ code, or a `panic!` in Rust code compiled or
/// linked with a different runtime) via an appropriate ABI (e.g. `"C-unwind"`)
/// is permitted, catching such an exception using this function will have one
/// of two behaviors, and it is unspecified which will occur:
///
/// * The process aborts, after executing all destructors of `f` and the
/// functions it called.
/// * The function returns a `Result::Err` containing an opaque type.
///
/// Finally, be **careful in how you drop the result of this function**. If it
/// is `Err`, it contains the panic payload, and dropping that may in turn
/// panic!
///
/// # Examples
///
/// ```
/// use std::panic;
///
/// let result = panic::catch_unwind(|| {
/// println!("hello!");
/// });
/// assert!(result.is_ok());
///
/// let result = panic::catch_unwind(|| {
/// panic!("oh no!");
/// });
/// assert!(result.is_err());
/// ```
#[stable(feature = "catch_unwind", since = "1.9.0")]
pub fn catch_unwind<F: FnOnce() -> R + UnwindSafe, R>(f: F) -> Result<R> {
unsafe { panicking::catch_unwind(f) }
}
/// Triggers a panic without invoking the panic hook.
///
/// This is designed to be used in conjunction with [`catch_unwind`] to, for
/// example, carry a panic across a layer of C code.
///
/// # Notes
///
/// Note that panics in Rust are not always implemented via unwinding, but they
/// may be implemented by aborting the process. If this function is called when
/// panics are implemented this way then this function will abort the process,
/// not trigger an unwind.
///
/// # Examples
///
/// ```should_panic
/// use std::panic;
///
/// let result = panic::catch_unwind(|| {
/// if 1 != 2 {
/// panic!("oh no!");
/// }
/// });
///
/// if let Err(err) = result {
/// panic::resume_unwind(err);
/// }
/// ```
#[stable(feature = "resume_unwind", since = "1.9.0")]
pub fn resume_unwind(payload: Box<dyn Any + Send>) -> ! {
panicking::resume_unwind(payload)
}
/// Makes all future panics abort directly without running the panic hook or unwinding.
///
/// There is no way to undo this; the effect lasts until the process exits or
/// execs (or the equivalent).
///
/// # Use after fork
///
/// This function is particularly useful for calling after `libc::fork`. After `fork`, in a
/// multithreaded program it is (on many platforms) not safe to call the allocator. It is also
/// generally highly undesirable for an unwind to unwind past the `fork`, because that results in
/// the unwind propagating to code that was only ever expecting to run in the parent.
///
/// `panic::always_abort()` helps avoid both of these. It directly avoids any further unwinding,
/// and if there is a panic, the abort will occur without allocating provided that the arguments to
/// panic can be formatted without allocating.
///
/// Examples
///
/// ```no_run
/// #![feature(panic_always_abort)]
/// use std::panic;
///
/// panic::always_abort();
///
/// let _ = panic::catch_unwind(|| {
/// panic!("inside the catch");
/// });
///
/// // We will have aborted already, due to the panic.
/// unreachable!();
/// ```
#[unstable(feature = "panic_always_abort", issue = "84438")]
pub fn always_abort() {
crate::panicking::panic_count::set_always_abort();
}
/// The configuration for whether and how the default panic hook will capture
/// and display the backtrace.
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
#[unstable(feature = "panic_backtrace_config", issue = "93346")]
#[non_exhaustive]
pub enum BacktraceStyle {
/// Prints a terser backtrace which ideally only contains relevant
/// information.
Short,
/// Prints a backtrace with all possible information.
Full,
/// Disable collecting and displaying backtraces.
Off,
}
impl BacktraceStyle {
pub(crate) fn full() -> Option<Self> {
if cfg!(feature = "backtrace") { Some(BacktraceStyle::Full) } else { None }
}
fn as_u8(self) -> u8 {
match self {
BacktraceStyle::Short => 1,
BacktraceStyle::Full => 2,
BacktraceStyle::Off => 3,
}
}
fn from_u8(s: u8) -> Option<Self> {
match s {
1 => Some(BacktraceStyle::Short),
2 => Some(BacktraceStyle::Full),
3 => Some(BacktraceStyle::Off),
_ => None,
}
}
}
// Tracks whether we should/can capture a backtrace, and how we should display
// that backtrace.
//
// Internally stores equivalent of an Option<BacktraceStyle>.
static SHOULD_CAPTURE: Atomic<u8> = AtomicU8::new(0);
/// Configures whether the default panic hook will capture and display a
/// backtrace.
///
/// The default value for this setting may be set by the `RUST_BACKTRACE`
/// environment variable; see the details in [`get_backtrace_style`].
#[unstable(feature = "panic_backtrace_config", issue = "93346")]
pub fn set_backtrace_style(style: BacktraceStyle) {
if cfg!(feature = "backtrace") {
// If the `backtrace` feature of this crate is enabled, set the backtrace style.
SHOULD_CAPTURE.store(style.as_u8(), Ordering::Relaxed);
}
}
/// Checks whether the standard library's panic hook will capture and print a
/// backtrace.
///
/// This function will, if a backtrace style has not been set via
/// [`set_backtrace_style`], read the environment variable `RUST_BACKTRACE` to
/// determine a default value for the backtrace formatting:
///
/// The first call to `get_backtrace_style` may read the `RUST_BACKTRACE`
/// environment variable if `set_backtrace_style` has not been called to
/// override the default value. After a call to `set_backtrace_style` or
/// `get_backtrace_style`, any changes to `RUST_BACKTRACE` will have no effect.
///
/// `RUST_BACKTRACE` is read according to these rules:
///
/// * `0` for `BacktraceStyle::Off`
/// * `full` for `BacktraceStyle::Full`
/// * `1` for `BacktraceStyle::Short`
/// * Other values are currently `BacktraceStyle::Short`, but this may change in
/// the future
///
/// Returns `None` if backtraces aren't currently supported.
#[unstable(feature = "panic_backtrace_config", issue = "93346")]
pub fn get_backtrace_style() -> Option<BacktraceStyle> {
if !cfg!(feature = "backtrace") {
// If the `backtrace` feature of this crate isn't enabled quickly return
// `Unsupported` so this can be constant propagated all over the place
// to optimize away callers.
return None;
}
let current = SHOULD_CAPTURE.load(Ordering::Relaxed);
if let Some(style) = BacktraceStyle::from_u8(current) {
return Some(style);
}
let format = match crate::env::var_os("RUST_BACKTRACE") {
Some(x) if &x == "0" => BacktraceStyle::Off,
Some(x) if &x == "full" => BacktraceStyle::Full,
Some(_) => BacktraceStyle::Short,
None if crate::sys::backtrace::FULL_BACKTRACE_DEFAULT => BacktraceStyle::Full,
None => BacktraceStyle::Off,
};
match SHOULD_CAPTURE.compare_exchange(0, format.as_u8(), Ordering::Relaxed, Ordering::Relaxed) {
Ok(_) => Some(format),
Err(new) => BacktraceStyle::from_u8(new),
}
}

894
crates/std/src/panicking.rs Normal file
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@@ -0,0 +1,894 @@
//! Implementation of various bits and pieces of the `panic!` macro and
//! associated runtime pieces.
//!
//! Specifically, this module contains the implementation of:
//!
//! * Panic hooks
//! * Executing a panic up to doing the actual implementation
//! * Shims around "try"
#![deny(unsafe_op_in_unsafe_fn)]
use core::panic::{Location, PanicPayload};
// make sure to use the stderr output configured
// by libtest in the real copy of std
#[cfg(test)]
use realstd::io::try_set_output_capture;
use crate::any::Any;
#[cfg(not(test))]
use crate::io::try_set_output_capture;
use crate::mem::{self, ManuallyDrop};
use crate::panic::{BacktraceStyle, PanicHookInfo};
use crate::sync::atomic::{Atomic, AtomicBool, Ordering};
use crate::sync::nonpoison::RwLock;
use crate::sys::backtrace;
use crate::sys::stdio::panic_output;
use crate::{fmt, intrinsics, process, thread};
// This forces codegen of the function called by panic!() inside the std crate, rather than in
// downstream crates. Primarily this is useful for rustc's codegen tests, which rely on noticing
// complete removal of panic from generated IR. Since begin_panic is inline(never), it's only
// codegen'd once per crate-graph so this pushes that to std rather than our codegen test crates.
//
// (See https://github.com/rust-lang/rust/pull/123244 for more info on why).
//
// If this is causing problems we can also modify those codegen tests to use a crate type like
// cdylib which doesn't export "Rust" symbols to downstream linkage units.
#[unstable(feature = "libstd_sys_internals", reason = "used by the panic! macro", issue = "none")]
#[doc(hidden)]
#[allow(dead_code)]
#[used(compiler)]
pub static EMPTY_PANIC: fn(&'static str) -> ! =
begin_panic::<&'static str> as fn(&'static str) -> !;
// Binary interface to the panic runtime that the standard library depends on.
//
// The standard library is tagged with `#![needs_panic_runtime]` (introduced in
// RFC 1513) to indicate that it requires some other crate tagged with
// `#![panic_runtime]` to exist somewhere. Each panic runtime is intended to
// implement these symbols (with the same signatures) so we can get matched up
// to them.
//
// One day this may look a little less ad-hoc with the compiler helping out to
// hook up these functions, but it is not this day!
#[allow(improper_ctypes)]
unsafe extern "C" {
#[rustc_std_internal_symbol]
fn __rust_panic_cleanup(payload: *mut u8) -> *mut (dyn Any + Send + 'static);
}
unsafe extern "Rust" {
/// `PanicPayload` lazily performs allocation only when needed (this avoids
/// allocations when using the "abort" panic runtime).
#[rustc_std_internal_symbol]
fn __rust_start_panic(payload: &mut dyn PanicPayload) -> u32;
}
/// This function is called by the panic runtime if FFI code catches a Rust
/// panic but doesn't rethrow it. We don't support this case since it messes
/// with our panic count.
#[cfg(not(test))]
#[rustc_std_internal_symbol]
extern "C" fn __rust_drop_panic() -> ! {
rtabort!("Rust panics must be rethrown");
}
/// This function is called by the panic runtime if it catches an exception
/// object which does not correspond to a Rust panic.
#[cfg(not(test))]
#[rustc_std_internal_symbol]
extern "C" fn __rust_foreign_exception() -> ! {
rtabort!("Rust cannot catch foreign exceptions");
}
#[derive(Default)]
enum Hook {
#[default]
Default,
Custom(Box<dyn Fn(&PanicHookInfo<'_>) + 'static + Sync + Send>),
}
impl Hook {
#[inline]
fn into_box(self) -> Box<dyn Fn(&PanicHookInfo<'_>) + 'static + Sync + Send> {
match self {
Hook::Default => Box::new(default_hook),
Hook::Custom(hook) => hook,
}
}
}
static HOOK: RwLock<Hook> = RwLock::new(Hook::Default);
/// Registers a custom panic hook, replacing the previously registered hook.
///
/// The panic hook is invoked when a thread panics, but before the panic runtime
/// is invoked. As such, the hook will run with both the aborting and unwinding
/// runtimes.
///
/// The default hook, which is registered at startup, prints a message to standard error and
/// generates a backtrace if requested. This behavior can be customized using the `set_hook` function.
/// The current hook can be retrieved while reinstating the default hook with the [`take_hook`]
/// function.
///
/// [`take_hook`]: ./fn.take_hook.html
///
/// The hook is provided with a `PanicHookInfo` struct which contains information
/// about the origin of the panic, including the payload passed to `panic!` and
/// the source code location from which the panic originated.
///
/// The panic hook is a global resource.
///
/// # Panics
///
/// Panics if called from a panicking thread.
///
/// # Examples
///
/// The following will print "Custom panic hook":
///
/// ```should_panic
/// use std::panic;
///
/// panic::set_hook(Box::new(|_| {
/// println!("Custom panic hook");
/// }));
///
/// panic!("Normal panic");
/// ```
#[stable(feature = "panic_hooks", since = "1.10.0")]
pub fn set_hook(hook: Box<dyn Fn(&PanicHookInfo<'_>) + 'static + Sync + Send>) {
if thread::panicking() {
panic!("cannot modify the panic hook from a panicking thread");
}
// Drop the old hook after changing the hook to avoid deadlocking if its
// destructor panics.
drop(HOOK.replace(Hook::Custom(hook)));
}
/// Unregisters the current panic hook and returns it, registering the default hook
/// in its place.
///
/// *See also the function [`set_hook`].*
///
/// [`set_hook`]: ./fn.set_hook.html
///
/// If the default hook is registered it will be returned, but remain registered.
///
/// # Panics
///
/// Panics if called from a panicking thread.
///
/// # Examples
///
/// The following will print "Normal panic":
///
/// ```should_panic
/// use std::panic;
///
/// panic::set_hook(Box::new(|_| {
/// println!("Custom panic hook");
/// }));
///
/// let _ = panic::take_hook();
///
/// panic!("Normal panic");
/// ```
#[must_use]
#[stable(feature = "panic_hooks", since = "1.10.0")]
pub fn take_hook() -> Box<dyn Fn(&PanicHookInfo<'_>) + 'static + Sync + Send> {
if thread::panicking() {
panic!("cannot modify the panic hook from a panicking thread");
}
HOOK.replace(Hook::Default).into_box()
}
/// Atomic combination of [`take_hook`] and [`set_hook`]. Use this to replace the panic handler with
/// a new panic handler that does something and then executes the old handler.
///
/// [`take_hook`]: ./fn.take_hook.html
/// [`set_hook`]: ./fn.set_hook.html
///
/// # Panics
///
/// Panics if called from a panicking thread.
///
/// # Examples
///
/// The following will print the custom message, and then the normal output of panic.
///
/// ```should_panic
/// #![feature(panic_update_hook)]
/// use std::panic;
///
/// // Equivalent to
/// // let prev = panic::take_hook();
/// // panic::set_hook(Box::new(move |info| {
/// // println!("...");
/// // prev(info);
/// // }));
/// panic::update_hook(move |prev, info| {
/// println!("Print custom message and execute panic handler as usual");
/// prev(info);
/// });
///
/// panic!("Custom and then normal");
/// ```
#[unstable(feature = "panic_update_hook", issue = "92649")]
pub fn update_hook<F>(hook_fn: F)
where
F: Fn(&(dyn Fn(&PanicHookInfo<'_>) + Send + Sync + 'static), &PanicHookInfo<'_>)
+ Sync
+ Send
+ 'static,
{
if thread::panicking() {
panic!("cannot modify the panic hook from a panicking thread");
}
let mut hook = HOOK.write();
let prev = mem::take(&mut *hook).into_box();
*hook = Hook::Custom(Box::new(move |info| hook_fn(&prev, info)));
}
/// The default panic handler.
#[optimize(size)]
fn default_hook(info: &PanicHookInfo<'_>) {
// If this is a double panic, make sure that we print a backtrace
// for this panic. Otherwise only print it if logging is enabled.
let backtrace = if info.force_no_backtrace() {
None
} else if panic_count::get_count() >= 2 {
BacktraceStyle::full()
} else {
crate::panic::get_backtrace_style()
};
// The current implementation always returns `Some`.
let location = info.location().unwrap();
let msg = payload_as_str(info.payload());
let write = #[optimize(size)]
|err: &mut dyn crate::io::Write| {
// Use a lock to prevent mixed output in multithreading context.
// Some platforms also require it when printing a backtrace, like `SymFromAddr` on Windows.
let mut lock = backtrace::lock();
thread::with_current_name(|name| {
let name = name.unwrap_or("<unnamed>");
let tid = thread::current_os_id();
// Try to write the panic message to a buffer first to prevent other concurrent outputs
// interleaving with it.
let mut buffer = [0u8; 512];
let mut cursor = crate::io::Cursor::new(&mut buffer[..]);
let write_msg = |dst: &mut dyn crate::io::Write| {
// We add a newline to ensure the panic message appears at the start of a line.
writeln!(dst, "\nthread '{name}' ({tid}) panicked at {location}:\n{msg}")
};
if write_msg(&mut cursor).is_ok() {
let pos = cursor.position() as usize;
let _ = err.write_all(&buffer[0..pos]);
} else {
// The message did not fit into the buffer, write it directly instead.
let _ = write_msg(err);
};
});
static FIRST_PANIC: Atomic<bool> = AtomicBool::new(true);
match backtrace {
Some(BacktraceStyle::Short) => {
todo!()
}
Some(BacktraceStyle::Full) => {
todo!()
}
Some(BacktraceStyle::Off) => {
if FIRST_PANIC.swap(false, Ordering::Relaxed) {
let _ = writeln!(
err,
"note: run with `RUST_BACKTRACE=1` environment variable to display a \
backtrace"
);
if cfg!(miri) {
let _ = writeln!(
err,
"note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` \
for the environment variable to have an effect"
);
}
}
}
// If backtraces aren't supported or are forced-off, do nothing.
None => {}
}
};
if let Ok(Some(local)) = try_set_output_capture(None) {
write(&mut *local.lock().unwrap_or_else(|e| e.into_inner()));
try_set_output_capture(Some(local)).ok();
} else if let Some(mut out) = panic_output() {
write(&mut out);
}
}
#[cfg(not(test))]
#[doc(hidden)]
#[cfg(panic = "immediate-abort")]
#[unstable(feature = "update_panic_count", issue = "none")]
pub mod panic_count {
/// A reason for forcing an immediate abort on panic.
#[derive(Debug)]
pub enum MustAbort {
AlwaysAbort,
PanicInHook,
}
#[inline]
pub fn increase(run_panic_hook: bool) -> Option<MustAbort> {
None
}
#[inline]
pub fn finished_panic_hook() {}
#[inline]
pub fn decrease() {}
#[inline]
pub fn set_always_abort() {}
// Disregards ALWAYS_ABORT_FLAG
#[inline]
#[must_use]
pub fn get_count() -> usize {
0
}
#[must_use]
#[inline]
pub fn count_is_zero() -> bool {
true
}
}
#[cfg(not(test))]
#[doc(hidden)]
#[cfg(not(panic = "immediate-abort"))]
#[unstable(feature = "update_panic_count", issue = "none")]
pub mod panic_count {
use crate::cell::Cell;
use crate::sync::atomic::{Atomic, AtomicUsize, Ordering};
const ALWAYS_ABORT_FLAG: usize = 1 << (usize::BITS - 1);
/// A reason for forcing an immediate abort on panic.
#[derive(Debug)]
pub enum MustAbort {
AlwaysAbort,
PanicInHook,
}
// Panic count for the current thread and whether a panic hook is currently
// being executed..
thread_local! {
static LOCAL_PANIC_COUNT: Cell<(usize, bool)> = const { Cell::new((0, false)) }
}
// Sum of panic counts from all threads. The purpose of this is to have
// a fast path in `count_is_zero` (which is used by `panicking`). In any particular
// thread, if that thread currently views `GLOBAL_PANIC_COUNT` as being zero,
// then `LOCAL_PANIC_COUNT` in that thread is zero. This invariant holds before
// and after increase and decrease, but not necessarily during their execution.
//
// Additionally, the top bit of GLOBAL_PANIC_COUNT (GLOBAL_ALWAYS_ABORT_FLAG)
// records whether panic::always_abort() has been called. This can only be
// set, never cleared.
// panic::always_abort() is usually called to prevent memory allocations done by
// the panic handling in the child created by `libc::fork`.
// Memory allocations performed in a child created with `libc::fork` are undefined
// behavior in most operating systems.
// Accessing LOCAL_PANIC_COUNT in a child created by `libc::fork` would lead to a memory
// allocation. Only GLOBAL_PANIC_COUNT can be accessed in this situation. This is
// sufficient because a child process will always have exactly one thread only.
// See also #85261 for details.
//
// This could be viewed as a struct containing a single bit and an n-1-bit
// value, but if we wrote it like that it would be more than a single word,
// and even a newtype around usize would be clumsy because we need atomics.
// But we use such a tuple for the return type of increase().
//
// Stealing a bit is fine because it just amounts to assuming that each
// panicking thread consumes at least 2 bytes of address space.
static GLOBAL_PANIC_COUNT: Atomic<usize> = AtomicUsize::new(0);
// Increases the global and local panic count, and returns whether an
// immediate abort is required.
//
// This also updates thread-local state to keep track of whether a panic
// hook is currently executing.
pub fn increase(run_panic_hook: bool) -> Option<MustAbort> {
let global_count = GLOBAL_PANIC_COUNT.fetch_add(1, Ordering::Relaxed);
if global_count & ALWAYS_ABORT_FLAG != 0 {
// Do *not* access thread-local state, we might be after a `fork`.
return Some(MustAbort::AlwaysAbort);
}
LOCAL_PANIC_COUNT.with(|c| {
let (count, in_panic_hook) = c.get();
if in_panic_hook {
return Some(MustAbort::PanicInHook);
}
c.set((count + 1, run_panic_hook));
None
})
}
pub fn finished_panic_hook() {
LOCAL_PANIC_COUNT.with(|c| {
let (count, _) = c.get();
c.set((count, false));
});
}
pub fn decrease() {
GLOBAL_PANIC_COUNT.fetch_sub(1, Ordering::Relaxed);
LOCAL_PANIC_COUNT.with(|c| {
let (count, _) = c.get();
c.set((count - 1, false));
});
}
pub fn set_always_abort() {
GLOBAL_PANIC_COUNT.fetch_or(ALWAYS_ABORT_FLAG, Ordering::Relaxed);
}
// Disregards ALWAYS_ABORT_FLAG
#[must_use]
pub fn get_count() -> usize {
LOCAL_PANIC_COUNT.with(|c| c.get().0)
}
// Disregards ALWAYS_ABORT_FLAG
#[must_use]
#[inline]
pub fn count_is_zero() -> bool {
if GLOBAL_PANIC_COUNT.load(Ordering::Relaxed) & !ALWAYS_ABORT_FLAG == 0 {
// Fast path: if `GLOBAL_PANIC_COUNT` is zero, all threads
// (including the current one) will have `LOCAL_PANIC_COUNT`
// equal to zero, so TLS access can be avoided.
//
// In terms of performance, a relaxed atomic load is similar to a normal
// aligned memory read (e.g., a mov instruction in x86), but with some
// compiler optimization restrictions. On the other hand, a TLS access
// might require calling a non-inlinable function (such as `__tls_get_addr`
// when using the GD TLS model).
true
} else {
is_zero_slow_path()
}
}
// Slow path is in a separate function to reduce the amount of code
// inlined from `count_is_zero`.
#[inline(never)]
#[cold]
fn is_zero_slow_path() -> bool {
LOCAL_PANIC_COUNT.with(|c| c.get().0 == 0)
}
}
#[cfg(test)]
pub use realstd::rt::panic_count;
/// Invoke a closure, capturing the cause of an unwinding panic if one occurs.
#[cfg(panic = "immediate-abort")]
pub unsafe fn catch_unwind<R, F: FnOnce() -> R>(f: F) -> Result<R, Box<dyn Any + Send>> {
Ok(f())
}
/// Invoke a closure, capturing the cause of an unwinding panic if one occurs.
#[cfg(not(panic = "immediate-abort"))]
pub unsafe fn catch_unwind<R, F: FnOnce() -> R>(f: F) -> Result<R, Box<dyn Any + Send>> {
union Data<F, R> {
f: ManuallyDrop<F>,
r: ManuallyDrop<R>,
p: ManuallyDrop<Box<dyn Any + Send>>,
}
// We do some sketchy operations with ownership here for the sake of
// performance. We can only pass pointers down to `do_call` (can't pass
// objects by value), so we do all the ownership tracking here manually
// using a union.
//
// We go through a transition where:
//
// * First, we set the data field `f` to be the argumentless closure that we're going to call.
// * When we make the function call, the `do_call` function below, we take
// ownership of the function pointer. At this point the `data` union is
// entirely uninitialized.
// * If the closure successfully returns, we write the return value into the
// data's return slot (field `r`).
// * If the closure panics (`do_catch` below), we write the panic payload into field `p`.
// * Finally, when we come back out of the `try` intrinsic we're
// in one of two states:
//
// 1. The closure didn't panic, in which case the return value was
// filled in. We move it out of `data.r` and return it.
// 2. The closure panicked, in which case the panic payload was
// filled in. We move it out of `data.p` and return it.
//
// Once we stack all that together we should have the "most efficient'
// method of calling a catch panic whilst juggling ownership.
let mut data = Data { f: ManuallyDrop::new(f) };
let data_ptr = (&raw mut data) as *mut u8;
// SAFETY:
//
// Access to the union's fields: this is `std` and we know that the `catch_unwind`
// intrinsic fills in the `r` or `p` union field based on its return value.
//
// The call to `intrinsics::catch_unwind` is made safe by:
// - `do_call`, the first argument, can be called with the initial `data_ptr`.
// - `do_catch`, the second argument, can be called with the `data_ptr` as well.
// See their safety preconditions for more information
unsafe {
return if intrinsics::catch_unwind(do_call::<F, R>, data_ptr, do_catch::<F, R>) == 0 {
Ok(ManuallyDrop::into_inner(data.r))
} else {
Err(ManuallyDrop::into_inner(data.p))
};
}
// We consider unwinding to be rare, so mark this function as cold. However,
// do not mark it no-inline -- that decision is best to leave to the
// optimizer (in most cases this function is not inlined even as a normal,
// non-cold function, though, as of the writing of this comment).
#[cold]
#[optimize(size)]
unsafe fn cleanup(payload: *mut u8) -> Box<dyn Any + Send + 'static> {
// SAFETY: The whole unsafe block hinges on a correct implementation of
// the panic handler `__rust_panic_cleanup`. As such we can only
// assume it returns the correct thing for `Box::from_raw` to work
// without undefined behavior.
let obj = unsafe { Box::from_raw(__rust_panic_cleanup(payload)) };
panic_count::decrease();
obj
}
// SAFETY:
// data must be non-NUL, correctly aligned, and a pointer to a `Data<F, R>`
// Its must contains a valid `f` (type: F) value that can be use to fill
// `data.r`.
//
// This function cannot be marked as `unsafe` because `intrinsics::catch_unwind`
// expects normal function pointers.
#[inline]
fn do_call<F: FnOnce() -> R, R>(data: *mut u8) {
// SAFETY: this is the responsibility of the caller, see above.
unsafe {
let data = data as *mut Data<F, R>;
let data = &mut (*data);
let f = ManuallyDrop::take(&mut data.f);
data.r = ManuallyDrop::new(f());
}
}
// We *do* want this part of the catch to be inlined: this allows the
// compiler to properly track accesses to the Data union and optimize it
// away most of the time.
//
// SAFETY:
// data must be non-NUL, correctly aligned, and a pointer to a `Data<F, R>`
// Since this uses `cleanup` it also hinges on a correct implementation of
// `__rustc_panic_cleanup`.
//
// This function cannot be marked as `unsafe` because `intrinsics::catch_unwind`
// expects normal function pointers.
#[inline]
#[rustc_nounwind] // `intrinsic::catch_unwind` requires catch fn to be nounwind
fn do_catch<F: FnOnce() -> R, R>(data: *mut u8, payload: *mut u8) {
// SAFETY: this is the responsibility of the caller, see above.
//
// When `__rustc_panic_cleaner` is correctly implemented we can rely
// on `obj` being the correct thing to pass to `data.p` (after wrapping
// in `ManuallyDrop`).
unsafe {
let data = data as *mut Data<F, R>;
let data = &mut (*data);
let obj = cleanup(payload);
data.p = ManuallyDrop::new(obj);
}
}
}
/// Determines whether the current thread is unwinding because of panic.
#[inline]
pub fn panicking() -> bool {
!panic_count::count_is_zero()
}
/// Entry point of panics from the core crate (`panic_impl` lang item).
#[cfg(not(any(test, doctest)))]
#[panic_handler]
pub fn panic_handler(info: &core::panic::PanicInfo<'_>) -> ! {
struct FormatStringPayload<'a> {
inner: &'a core::panic::PanicMessage<'a>,
string: Option<String>,
}
impl FormatStringPayload<'_> {
fn fill(&mut self) -> &mut String {
let inner = self.inner;
// Lazily, the first time this gets called, run the actual string formatting.
self.string.get_or_insert_with(|| {
let mut s = String::new();
let mut fmt = fmt::Formatter::new(&mut s, fmt::FormattingOptions::new());
let _err = fmt::Display::fmt(&inner, &mut fmt);
s
})
}
}
unsafe impl PanicPayload for FormatStringPayload<'_> {
fn take_box(&mut self) -> *mut (dyn Any + Send) {
// We do two allocations here, unfortunately. But (a) they're required with the current
// scheme, and (b) we don't handle panic + OOM properly anyway (see comment in
// begin_panic below).
let contents = mem::take(self.fill());
Box::into_raw(Box::new(contents))
}
fn get(&mut self) -> &(dyn Any + Send) {
self.fill()
}
}
impl fmt::Display for FormatStringPayload<'_> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
if let Some(s) = &self.string {
f.write_str(s)
} else {
fmt::Display::fmt(&self.inner, f)
}
}
}
struct StaticStrPayload(&'static str);
unsafe impl PanicPayload for StaticStrPayload {
fn take_box(&mut self) -> *mut (dyn Any + Send) {
Box::into_raw(Box::new(self.0))
}
fn get(&mut self) -> &(dyn Any + Send) {
&self.0
}
fn as_str(&mut self) -> Option<&str> {
Some(self.0)
}
}
impl fmt::Display for StaticStrPayload {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(self.0)
}
}
let loc = info.location().unwrap(); // The current implementation always returns Some
let msg = info.message();
crate::sys::backtrace::__rust_end_short_backtrace(move || {
if let Some(s) = msg.as_str() {
panic_with_hook(
&mut StaticStrPayload(s),
loc,
info.can_unwind(),
info.force_no_backtrace(),
);
} else {
panic_with_hook(
&mut FormatStringPayload { inner: &msg, string: None },
loc,
info.can_unwind(),
info.force_no_backtrace(),
);
}
})
}
/// This is the entry point of panicking for the non-format-string variants of
/// panic!() and assert!(). In particular, this is the only entry point that supports
/// arbitrary payloads, not just format strings.
#[unstable(feature = "libstd_sys_internals", reason = "used by the panic! macro", issue = "none")]
#[cfg_attr(not(any(test, doctest)), lang = "begin_panic")]
// lang item for CTFE panic support
// never inline unless panic=immediate-abort to avoid code
// bloat at the call sites as much as possible
#[cfg_attr(not(panic = "immediate-abort"), inline(never), cold, optimize(size))]
#[cfg_attr(panic = "immediate-abort", inline)]
#[track_caller]
#[rustc_do_not_const_check] // hooked by const-eval
pub const fn begin_panic<M: Any + Send>(msg: M) -> ! {
if cfg!(panic = "immediate-abort") {
intrinsics::abort()
}
struct Payload<A> {
inner: Option<A>,
}
unsafe impl<A: Send + 'static> PanicPayload for Payload<A> {
fn take_box(&mut self) -> *mut (dyn Any + Send) {
// Note that this should be the only allocation performed in this code path. Currently
// this means that panic!() on OOM will invoke this code path, but then again we're not
// really ready for panic on OOM anyway. If we do start doing this, then we should
// propagate this allocation to be performed in the parent of this thread instead of the
// thread that's panicking.
let data = match self.inner.take() {
Some(a) => Box::new(a) as Box<dyn Any + Send>,
None => process::abort(),
};
Box::into_raw(data)
}
fn get(&mut self) -> &(dyn Any + Send) {
match self.inner {
Some(ref a) => a,
None => process::abort(),
}
}
}
impl<A: 'static> fmt::Display for Payload<A> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match &self.inner {
Some(a) => f.write_str(payload_as_str(a)),
None => process::abort(),
}
}
}
let loc = Location::caller();
crate::sys::backtrace::__rust_end_short_backtrace(move || {
panic_with_hook(
&mut Payload { inner: Some(msg) },
loc,
/* can_unwind */ true,
/* force_no_backtrace */ false,
)
})
}
fn payload_as_str(payload: &dyn Any) -> &str {
if let Some(&s) = payload.downcast_ref::<&'static str>() {
s
} else if let Some(s) = payload.downcast_ref::<String>() {
s.as_str()
} else {
"Box<dyn Any>"
}
}
/// Central point for dispatching panics.
///
/// Executes the primary logic for a panic, including checking for recursive
/// panics, panic hooks, and finally dispatching to the panic runtime to either
/// abort or unwind.
#[optimize(size)]
fn panic_with_hook(
payload: &mut dyn PanicPayload,
location: &Location<'_>,
can_unwind: bool,
force_no_backtrace: bool,
) -> ! {
let must_abort = panic_count::increase(true);
// Check if we need to abort immediately.
if let Some(must_abort) = must_abort {
match must_abort {
panic_count::MustAbort::PanicInHook => {
// Don't try to format the message in this case, perhaps that is causing the
// recursive panics. However if the message is just a string, no user-defined
// code is involved in printing it, so that is risk-free.
let message: &str = payload.as_str().unwrap_or_default();
rtprintpanic!(
"panicked at {location}:\n{message}\nthread panicked while processing panic. aborting.\n"
);
}
panic_count::MustAbort::AlwaysAbort => {
// Unfortunately, this does not print a backtrace, because creating
// a `Backtrace` will allocate, which we must avoid here.
rtprintpanic!("aborting due to panic at {location}:\n{payload}\n");
}
}
crate::process::abort();
}
match *HOOK.read() {
// Some platforms (like wasm) know that printing to stderr won't ever actually
// print anything, and if that's the case we can skip the default
// hook. Since string formatting happens lazily when calling `payload`
// methods, this means we avoid formatting the string at all!
// (The panic runtime might still call `payload.take_box()` though and trigger
// formatting.)
Hook::Default if panic_output().is_none() => {}
Hook::Default => {
default_hook(&PanicHookInfo::new(
location,
payload.get(),
can_unwind,
force_no_backtrace,
));
}
Hook::Custom(ref hook) => {
hook(&PanicHookInfo::new(location, payload.get(), can_unwind, force_no_backtrace));
}
}
// Indicate that we have finished executing the panic hook. After this point
// it is fine if there is a panic while executing destructors, as long as it
// it contained within a `catch_unwind`.
panic_count::finished_panic_hook();
if !can_unwind {
// If a thread panics while running destructors or tries to unwind
// through a nounwind function (e.g. extern "C") then we cannot continue
// unwinding and have to abort immediately.
rtprintpanic!("thread caused non-unwinding panic. aborting.\n");
crate::process::abort();
}
rust_panic(payload)
}
/// This is the entry point for `resume_unwind`.
/// It just forwards the payload to the panic runtime.
#[cfg_attr(panic = "immediate-abort", inline)]
pub fn resume_unwind(payload: Box<dyn Any + Send>) -> ! {
panic_count::increase(false);
struct RewrapBox(Box<dyn Any + Send>);
unsafe impl PanicPayload for RewrapBox {
fn take_box(&mut self) -> *mut (dyn Any + Send) {
Box::into_raw(mem::replace(&mut self.0, Box::new(())))
}
fn get(&mut self) -> &(dyn Any + Send) {
&*self.0
}
}
impl fmt::Display for RewrapBox {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(payload_as_str(&self.0))
}
}
rust_panic(&mut RewrapBox(payload))
}
/// A function with a fixed suffix (through `rustc_std_internal_symbol`)
/// on which to slap yer breakpoints.
#[inline(never)]
#[cfg_attr(not(test), rustc_std_internal_symbol)]
#[cfg(not(panic = "immediate-abort"))]
fn rust_panic(msg: &mut dyn PanicPayload) -> ! {
let code = unsafe { __rust_start_panic(msg) };
rtabort!("failed to initiate panic, error {code}")
}
#[cfg_attr(not(test), rustc_std_internal_symbol)]
#[cfg(panic = "immediate-abort")]
fn rust_panic(_: &mut dyn PanicPayload) -> ! {
crate::intrinsics::abort();
}

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pub mod rust_2024 {
pub use crate::print;
pub use crate::println;
pub use alloc::format;
pub use alloc::vec;
#[stable(feature = "rust1", since = "1.0.0")]
#[doc(no_inline)]
pub use crate::borrow::ToOwned;
#[stable(feature = "rust1", since = "1.0.0")]
#[doc(no_inline)]
pub use crate::boxed::Box;
#[stable(feature = "rust1", since = "1.0.0")]
#[doc(no_inline)]
pub use crate::string::{String, ToString};
#[stable(feature = "rust1", since = "1.0.0")]
#[doc(no_inline)]
pub use crate::vec::Vec;
// Re-exported built-in macros and traits
#[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
#[doc(no_inline)]
#[expect(deprecated)]
pub use core::prelude::v1::{
Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, assert, assert_eq,
assert_ne, cfg, column, compile_error, concat, debug_assert, debug_assert_eq,
debug_assert_ne, env, file, format_args, include, include_bytes, include_str, line,
matches, module_path, option_env, stringify, todo, r#try, unimplemented, unreachable,
write, writeln,
};
#[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
#[doc(no_inline)]
pub use crate::thread_local;
#[stable(feature = "cfg_select", since = "1.95.0")]
#[doc(no_inline)]
pub use core::prelude::v1::cfg_select;
#[unstable(
feature = "concat_bytes",
issue = "87555",
reason = "`concat_bytes` is not stable enough for use and is subject to change"
)]
#[doc(no_inline)]
pub use core::prelude::v1::concat_bytes;
#[unstable(feature = "const_format_args", issue = "none")]
#[doc(no_inline)]
pub use core::prelude::v1::const_format_args;
#[unstable(
feature = "log_syntax",
issue = "29598",
reason = "`log_syntax!` is not stable enough for use and is subject to change"
)]
#[doc(no_inline)]
pub use core::prelude::v1::log_syntax;
#[unstable(
feature = "trace_macros",
issue = "29598",
reason = "`trace_macros` is not stable enough for use and is subject to change"
)]
#[doc(no_inline)]
pub use core::prelude::v1::trace_macros;
// Do not `doc(no_inline)` so that they become doc items on their own
// (no public module for them to be re-exported from).
#[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
pub use core::prelude::v1::{
alloc_error_handler, bench, derive, global_allocator, test, test_case,
};
#[unstable(feature = "derive_const", issue = "118304")]
pub use core::prelude::v1::derive_const;
// Do not `doc(no_inline)` either.
#[unstable(
feature = "cfg_accessible",
issue = "64797",
reason = "`cfg_accessible` is not fully implemented"
)]
pub use core::prelude::v1::cfg_accessible;
// Do not `doc(no_inline)` either.
#[unstable(
feature = "cfg_eval",
issue = "82679",
reason = "`cfg_eval` is a recently implemented feature"
)]
pub use core::prelude::v1::cfg_eval;
// Do not `doc(no_inline)` either.
#[unstable(
feature = "type_ascription",
issue = "23416",
reason = "placeholder syntax for type ascription"
)]
pub use core::prelude::v1::type_ascribe;
// Do not `doc(no_inline)` either.
#[unstable(
feature = "deref_patterns",
issue = "87121",
reason = "placeholder syntax for deref patterns"
)]
pub use core::prelude::v1::deref;
// Do not `doc(no_inline)` either.
#[unstable(
feature = "type_alias_impl_trait",
issue = "63063",
reason = "`type_alias_impl_trait` has open design concerns"
)]
pub use core::prelude::v1::define_opaque;
#[unstable(feature = "extern_item_impls", issue = "125418")]
pub use core::prelude::v1::{eii, unsafe_eii};
#[unstable(feature = "eii_internals", issue = "none")]
pub use core::prelude::v1::eii_declaration;
#[stable(feature = "prelude_2021", since = "1.55.0")]
#[doc(no_inline)]
pub use core::prelude::rust_2021::*;
#[stable(feature = "prelude_2024", since = "1.85.0")]
#[doc(no_inline)]
pub use core::prelude::rust_2024::*;
#[stable(feature = "rust1", since = "1.0.0")]
#[doc(no_inline)]
pub use crate::convert::{AsMut, AsRef, From, Into};
extern crate alloc;
struct GlobalAllocator;
#[core::prelude::v1::global_allocator]
static GLOBAL_ALLOCATOR: GlobalAllocator = GlobalAllocator;
unsafe impl core::alloc::GlobalAlloc for GlobalAllocator {
unsafe fn alloc(&self, layout: core::alloc::Layout) -> *mut u8 {
crate::syscall::alloc(layout)
}
unsafe fn dealloc(&self, ptr: *mut u8, layout: core::alloc::Layout) {
crate::syscall::dealloc(ptr, layout)
}
}
// #[panic_handler]
// fn panic(_panic_info: &core::panic::PanicInfo) -> ! {
// // TODO print
// loop {}
// }
/// # Safety
/// `argc` and `argv` are passed by the kernel
#[unsafe(no_mangle)]
pub unsafe extern "C" fn _start(argc: isize, argv: *const *const u8) -> isize {
unsafe extern "Rust" {
fn main(argc: isize, argv: *const *const u8) -> isize;
}
unsafe { main(argc, argv) }
}
#[lang = "start"]
pub fn lang_start<T: crate::process::Termination + 'static>(
main: fn() -> T,
argc: isize,
argv: *const *const u8,
_sigpipe: u8,
) -> isize {
println!("{}", argc);
println!("{:?}", argv);
main().report().to_isize()
}
}

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pub struct ExitCode(isize);
impl ExitCode {
pub const SUCCESS: ExitCode = ExitCode(0);
pub fn to_isize(self) -> isize {
self.0
}
}
#[lang = "termination"]
pub trait Termination {
/// Is called to get the representation of the value as status code.
/// This status code is returned to the operating system.
fn report(self) -> ExitCode;
}
impl Termination for () {
#[inline]
fn report(self) -> ExitCode {
ExitCode::SUCCESS
}
}
impl Termination for isize {
#[inline]
fn report(self) -> ExitCode {
ExitCode(self)
}
}
pub fn abort() -> ! {
loop {}
}

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macro_rules! rtabort {
($($t:tt)*) => {{
loop {}
}};
}
macro_rules! rtprintpanic {
($($t:tt)*) => {{}};
}

85
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pub mod barrier;
pub mod lazy_lock;
pub mod mpmc;
pub mod mpsc;
pub mod nonpoison;
pub mod once;
pub mod once_lock;
pub mod poison;
pub mod reentrant_lock;
#[stable(feature = "rust1", since = "1.0.0")]
pub use core::sync::atomic;
pub use once::Once;
pub use once::OnceState;
pub use poison::LockResult;
pub use poison::Mutex;
pub use poison::MutexGuard;
pub use poison::PoisonError;
pub use poison::TryLockError;
pub use poison::TryLockResult;
pub use poison::Condvar;
pub use poison::RwLock;
pub use once_lock::OnceLock;
pub use reentrant_lock::ReentrantLock;
pub use reentrant_lock::ReentrantLockGuard;
pub use alloc_crate::sync::Arc;
#[derive(Debug, PartialEq, Eq, Copy, Clone)]
#[stable(feature = "wait_timeout", since = "1.5.0")]
pub struct WaitTimeoutResult(bool);
impl WaitTimeoutResult {
/// Returns `true` if the wait was known to have timed out.
///
/// # Examples
///
/// This example spawns a thread which will sleep 20 milliseconds before
/// updating a boolean value and then notifying the condvar.
///
/// The main thread will wait with a 10 millisecond timeout on the condvar
/// and will leave the loop upon timeout.
///
/// ```
/// use std::sync::{Arc, Condvar, Mutex};
/// use std::thread;
/// use std::time::Duration;
///
/// let pair = Arc::new((Mutex::new(false), Condvar::new()));
/// let pair2 = Arc::clone(&pair);
///
/// # let handle =
/// thread::spawn(move || {
/// let (lock, cvar) = &*pair2;
///
/// // Let's wait 20 milliseconds before notifying the condvar.
/// thread::sleep(Duration::from_millis(20));
///
/// let mut started = lock.lock().unwrap();
/// // We update the boolean value.
/// *started = true;
/// cvar.notify_one();
/// });
///
/// // Wait for the thread to start up.
/// let (lock, cvar) = &*pair;
/// loop {
/// // Let's put a timeout on the condvar's wait.
/// let result = cvar.wait_timeout(lock.lock().unwrap(), Duration::from_millis(10)).unwrap();
/// // 10 milliseconds have passed.
/// if result.1.timed_out() {
/// // timed out now and we can leave.
/// break
/// }
/// }
/// # // Prevent leaks for Miri.
/// # let _ = handle.join();
/// ```
#[must_use]
#[stable(feature = "wait_timeout", since = "1.5.0")]
pub fn timed_out(&self) -> bool {
self.0
}
}

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use crate::fmt;
use crate::panic::RefUnwindSafe;
use crate::sync::nonpoison::{Condvar, Mutex};
/// A barrier enables multiple threads to synchronize the beginning
/// of some computation.
///
/// # Examples
///
/// ```
/// use std::sync::Barrier;
/// use std::thread;
///
/// let n = 10;
/// let barrier = Barrier::new(n);
/// thread::scope(|s| {
/// for _ in 0..n {
/// // The same messages will be printed together.
/// // You will NOT see any interleaving.
/// s.spawn(|| {
/// println!("before wait");
/// barrier.wait();
/// println!("after wait");
/// });
/// }
/// });
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub struct Barrier {
lock: Mutex<BarrierState>,
cvar: Condvar,
num_threads: usize,
}
#[stable(feature = "unwind_safe_lock_refs", since = "1.12.0")]
impl RefUnwindSafe for Barrier {}
// The inner state of a double barrier
struct BarrierState {
count: usize,
generation_id: usize,
}
/// A `BarrierWaitResult` is returned by [`Barrier::wait()`] when all threads
/// in the [`Barrier`] have rendezvoused.
///
/// # Examples
///
/// ```
/// use std::sync::Barrier;
///
/// let barrier = Barrier::new(1);
/// let barrier_wait_result = barrier.wait();
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub struct BarrierWaitResult(bool);
#[stable(feature = "std_debug", since = "1.16.0")]
impl fmt::Debug for Barrier {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("Barrier").finish_non_exhaustive()
}
}
impl Barrier {
/// Creates a new barrier that can block a given number of threads.
///
/// A barrier will block all threads which call [`wait()`] until the `n`th thread calls [`wait()`],
/// and then wake up all threads at once.
///
/// [`wait()`]: Barrier::wait
///
/// # Examples
///
/// ```
/// use std::sync::Barrier;
///
/// let barrier = Barrier::new(10);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_barrier", since = "1.78.0")]
#[must_use]
#[inline]
pub const fn new(n: usize) -> Barrier {
Barrier {
lock: Mutex::new(BarrierState { count: 0, generation_id: 0 }),
cvar: Condvar::new(),
num_threads: n,
}
}
/// Blocks the current thread until all threads have rendezvoused here.
///
/// Barriers are re-usable after all threads have rendezvoused once, and can
/// be used continuously.
///
/// A single (arbitrary) thread will receive a [`BarrierWaitResult`] that
/// returns `true` from [`BarrierWaitResult::is_leader()`] when returning
/// from this function, and all other threads will receive a result that
/// will return `false` from [`BarrierWaitResult::is_leader()`].
///
/// # Examples
///
/// ```
/// use std::sync::Barrier;
/// use std::thread;
///
/// let n = 10;
/// let barrier = Barrier::new(n);
/// thread::scope(|s| {
/// for _ in 0..n {
/// // The same messages will be printed together.
/// // You will NOT see any interleaving.
/// s.spawn(|| {
/// println!("before wait");
/// barrier.wait();
/// println!("after wait");
/// });
/// }
/// });
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn wait(&self) -> BarrierWaitResult {
let mut lock = self.lock.lock();
let local_gen = lock.generation_id;
lock.count += 1;
if lock.count < self.num_threads {
self.cvar.wait_while(&mut lock, |state| local_gen == state.generation_id);
BarrierWaitResult(false)
} else {
lock.count = 0;
lock.generation_id = lock.generation_id.wrapping_add(1);
self.cvar.notify_all();
BarrierWaitResult(true)
}
}
}
#[stable(feature = "std_debug", since = "1.16.0")]
impl fmt::Debug for BarrierWaitResult {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("BarrierWaitResult").field("is_leader", &self.is_leader()).finish()
}
}
impl BarrierWaitResult {
/// Returns `true` if this thread is the "leader thread" for the call to
/// [`Barrier::wait()`].
///
/// Only one thread will have `true` returned from their result, all other
/// threads will have `false` returned.
///
/// # Examples
///
/// ```
/// use std::sync::Barrier;
///
/// let barrier = Barrier::new(1);
/// let barrier_wait_result = barrier.wait();
/// println!("{:?}", barrier_wait_result.is_leader());
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[must_use]
pub fn is_leader(&self) -> bool {
self.0
}
}

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use super::once::OnceExclusiveState;
use crate::cell::UnsafeCell;
use crate::mem::ManuallyDrop;
use crate::ops::{Deref, DerefMut};
use crate::panic::{RefUnwindSafe, UnwindSafe};
use crate::sync::Once;
use crate::{fmt, ptr};
// We use the state of a Once as discriminant value. Upon creation, the state is
// "incomplete" and `f` contains the initialization closure. In the first call to
// `call_once`, `f` is taken and run. If it succeeds, `value` is set and the state
// is changed to "complete". If it panics, the Once is poisoned, so none of the
// two fields is initialized.
union Data<T, F> {
value: ManuallyDrop<T>,
f: ManuallyDrop<F>,
}
/// A value which is initialized on the first access.
///
/// This type is a thread-safe [`LazyCell`], and can be used in statics.
/// Since initialization may be called from multiple threads, any
/// dereferencing call will block the calling thread if another
/// initialization routine is currently running.
///
/// [`LazyCell`]: crate::cell::LazyCell
///
/// # Poisoning
///
/// If the initialization closure passed to [`LazyLock::new`] panics, the lock will be poisoned.
/// Once the lock is poisoned, any threads that attempt to access this lock (via a dereference
/// or via an explicit call to [`force()`]) will panic.
///
/// This concept is similar to that of poisoning in the [`std::sync::poison`] module. A key
/// difference, however, is that poisoning in `LazyLock` is _unrecoverable_. All future accesses of
/// the lock from other threads will panic, whereas a type in [`std::sync::poison`] like
/// [`std::sync::poison::Mutex`] allows recovery via [`PoisonError::into_inner()`].
///
/// [`force()`]: LazyLock::force
/// [`std::sync::poison`]: crate::sync::poison
/// [`std::sync::poison::Mutex`]: crate::sync::poison::Mutex
/// [`PoisonError::into_inner()`]: crate::sync::poison::PoisonError::into_inner
///
/// # Examples
///
/// Initialize static variables with `LazyLock`.
/// ```
/// use std::sync::LazyLock;
///
/// // Note: static items do not call [`Drop`] on program termination, so this won't be deallocated.
/// // this is fine, as the OS can deallocate the terminated program faster than we can free memory
/// // but tools like valgrind might report "memory leaks" as it isn't obvious this is intentional.
/// static DEEP_THOUGHT: LazyLock<String> = LazyLock::new(|| {
/// # mod another_crate {
/// # pub fn great_question() -> String { "42".to_string() }
/// # }
/// // M3 Ultra takes about 16 million years in --release config
/// another_crate::great_question()
/// });
///
/// // The `String` is built, stored in the `LazyLock`, and returned as `&String`.
/// let _ = &*DEEP_THOUGHT;
/// ```
///
/// Initialize fields with `LazyLock`.
/// ```
/// use std::sync::LazyLock;
///
/// #[derive(Debug)]
/// struct UseCellLock {
/// number: LazyLock<u32>,
/// }
/// fn main() {
/// let lock: LazyLock<u32> = LazyLock::new(|| 0u32);
///
/// let data = UseCellLock { number: lock };
/// println!("{}", *data.number);
/// }
/// ```
#[stable(feature = "lazy_cell", since = "1.80.0")]
pub struct LazyLock<T, F = fn() -> T> {
// FIXME(nonpoison_once): if possible, switch to nonpoison version once it is available
once: Once,
data: UnsafeCell<Data<T, F>>,
}
impl<T, F: FnOnce() -> T> LazyLock<T, F> {
/// Creates a new lazy value with the given initializing function.
///
/// # Examples
///
/// ```
/// use std::sync::LazyLock;
///
/// let hello = "Hello, World!".to_string();
///
/// let lazy = LazyLock::new(|| hello.to_uppercase());
///
/// assert_eq!(&*lazy, "HELLO, WORLD!");
/// ```
#[inline]
#[stable(feature = "lazy_cell", since = "1.80.0")]
#[rustc_const_stable(feature = "lazy_cell", since = "1.80.0")]
pub const fn new(f: F) -> LazyLock<T, F> {
LazyLock { once: Once::new(), data: UnsafeCell::new(Data { f: ManuallyDrop::new(f) }) }
}
/// Creates a new lazy value that is already initialized.
#[inline]
#[cfg(test)]
pub(crate) fn preinit(value: T) -> LazyLock<T, F> {
let once = Once::new();
once.call_once(|| {});
LazyLock { once, data: UnsafeCell::new(Data { value: ManuallyDrop::new(value) }) }
}
/// Consumes this `LazyLock` returning the stored value.
///
/// Returns `Ok(value)` if `Lazy` is initialized and `Err(f)` otherwise.
///
/// # Panics
///
/// Panics if the lock is poisoned.
///
/// # Examples
///
/// ```
/// #![feature(lazy_cell_into_inner)]
///
/// use std::sync::LazyLock;
///
/// let hello = "Hello, World!".to_string();
///
/// let lazy = LazyLock::new(|| hello.to_uppercase());
///
/// assert_eq!(&*lazy, "HELLO, WORLD!");
/// assert_eq!(LazyLock::into_inner(lazy).ok(), Some("HELLO, WORLD!".to_string()));
/// ```
#[unstable(feature = "lazy_cell_into_inner", issue = "125623")]
pub fn into_inner(mut this: Self) -> Result<T, F> {
let state = this.once.state();
match state {
OnceExclusiveState::Poisoned => panic_poisoned(),
state => {
let this = ManuallyDrop::new(this);
let data = unsafe { ptr::read(&this.data) }.into_inner();
match state {
OnceExclusiveState::Incomplete => {
Err(ManuallyDrop::into_inner(unsafe { data.f }))
}
OnceExclusiveState::Complete => {
Ok(ManuallyDrop::into_inner(unsafe { data.value }))
}
OnceExclusiveState::Poisoned => unreachable!(),
}
}
}
}
/// Forces the evaluation of this lazy value and returns a mutable reference to
/// the result.
///
/// # Panics
///
/// If the initialization closure panics (the one that is passed to the [`new()`] method), the
/// panic is propagated to the caller, and the lock becomes poisoned. This will cause all future
/// accesses of the lock (via [`force()`] or a dereference) to panic.
///
/// [`new()`]: LazyLock::new
/// [`force()`]: LazyLock::force
///
/// # Examples
///
/// ```
/// use std::sync::LazyLock;
///
/// let mut lazy = LazyLock::new(|| 92);
///
/// let p = LazyLock::force_mut(&mut lazy);
/// assert_eq!(*p, 92);
/// *p = 44;
/// assert_eq!(*lazy, 44);
/// ```
#[inline]
#[stable(feature = "lazy_get", since = "1.94.0")]
pub fn force_mut(this: &mut LazyLock<T, F>) -> &mut T {
#[cold]
/// # Safety
/// May only be called when the state is `Incomplete`.
unsafe fn really_init_mut<T, F: FnOnce() -> T>(this: &mut LazyLock<T, F>) -> &mut T {
struct PoisonOnPanic<'a, T, F>(&'a mut LazyLock<T, F>);
impl<T, F> Drop for PoisonOnPanic<'_, T, F> {
#[inline]
fn drop(&mut self) {
self.0.once.set_state(OnceExclusiveState::Poisoned);
}
}
// SAFETY: We always poison if the initializer panics (then we never check the data),
// or set the data on success.
let f = unsafe { ManuallyDrop::take(&mut this.data.get_mut().f) };
// INVARIANT: Initiated from mutable reference, don't drop because we read it.
let guard = PoisonOnPanic(this);
let data = f();
guard.0.data.get_mut().value = ManuallyDrop::new(data);
guard.0.once.set_state(OnceExclusiveState::Complete);
core::mem::forget(guard);
// SAFETY: We put the value there above.
unsafe { &mut this.data.get_mut().value }
}
let state = this.once.state();
match state {
OnceExclusiveState::Poisoned => panic_poisoned(),
// SAFETY: The `Once` states we completed the initialization.
OnceExclusiveState::Complete => unsafe { &mut this.data.get_mut().value },
// SAFETY: The state is `Incomplete`.
OnceExclusiveState::Incomplete => unsafe { really_init_mut(this) },
}
}
/// Forces the evaluation of this lazy value and returns a reference to
/// result. This is equivalent to the `Deref` impl, but is explicit.
///
/// This method will block the calling thread if another initialization
/// routine is currently running.
///
/// # Panics
///
/// If the initialization closure panics (the one that is passed to the [`new()`] method), the
/// panic is propagated to the caller, and the lock becomes poisoned. This will cause all future
/// accesses of the lock (via [`force()`] or a dereference) to panic.
///
/// [`new()`]: LazyLock::new
/// [`force()`]: LazyLock::force
///
/// # Examples
///
/// ```
/// use std::sync::LazyLock;
///
/// let lazy = LazyLock::new(|| 92);
///
/// assert_eq!(LazyLock::force(&lazy), &92);
/// assert_eq!(&*lazy, &92);
/// ```
#[inline]
#[stable(feature = "lazy_cell", since = "1.80.0")]
#[rustc_should_not_be_called_on_const_items]
pub fn force(this: &LazyLock<T, F>) -> &T {
this.once.call_once_force(|state| {
if state.is_poisoned() {
panic_poisoned();
}
// SAFETY: `call_once` only runs this closure once, ever.
let data = unsafe { &mut *this.data.get() };
let f = unsafe { ManuallyDrop::take(&mut data.f) };
let value = f();
data.value = ManuallyDrop::new(value);
});
// SAFETY:
// There are four possible scenarios:
// * the closure was called and initialized `value`.
// * the closure was called and panicked, so this point is never reached.
// * the closure was not called, but a previous call initialized `value`.
// * the closure was not called because the Once is poisoned, which we handled above.
// So `value` has definitely been initialized and will not be modified again.
unsafe { &*(*this.data.get()).value }
}
}
impl<T, F> LazyLock<T, F> {
/// Returns a mutable reference to the value if initialized. Otherwise (if uninitialized or
/// poisoned), returns `None`.
///
/// # Examples
///
/// ```
/// use std::sync::LazyLock;
///
/// let mut lazy = LazyLock::new(|| 92);
///
/// assert_eq!(LazyLock::get_mut(&mut lazy), None);
/// let _ = LazyLock::force(&lazy);
/// *LazyLock::get_mut(&mut lazy).unwrap() = 44;
/// assert_eq!(*lazy, 44);
/// ```
#[inline]
#[stable(feature = "lazy_get", since = "1.94.0")]
pub fn get_mut(this: &mut LazyLock<T, F>) -> Option<&mut T> {
// `state()` does not perform an atomic load, so prefer it over `is_complete()`.
let state = this.once.state();
match state {
// SAFETY:
// The closure has been run successfully, so `value` has been initialized.
OnceExclusiveState::Complete => Some(unsafe { &mut this.data.get_mut().value }),
_ => None,
}
}
/// Returns a reference to the value if initialized. Otherwise (if uninitialized or poisoned),
/// returns `None`.
///
/// # Examples
///
/// ```
/// use std::sync::LazyLock;
///
/// let lazy = LazyLock::new(|| 92);
///
/// assert_eq!(LazyLock::get(&lazy), None);
/// let _ = LazyLock::force(&lazy);
/// assert_eq!(LazyLock::get(&lazy), Some(&92));
/// ```
#[inline]
#[stable(feature = "lazy_get", since = "1.94.0")]
#[rustc_should_not_be_called_on_const_items]
pub fn get(this: &LazyLock<T, F>) -> Option<&T> {
if this.once.is_completed() {
// SAFETY:
// The closure has been run successfully, so `value` has been initialized
// and will not be modified again.
Some(unsafe { &(*this.data.get()).value })
} else {
None
}
}
}
#[stable(feature = "lazy_cell", since = "1.80.0")]
impl<T, F> Drop for LazyLock<T, F> {
fn drop(&mut self) {
match self.once.state() {
OnceExclusiveState::Incomplete => unsafe {
ManuallyDrop::drop(&mut self.data.get_mut().f)
},
OnceExclusiveState::Complete => unsafe {
ManuallyDrop::drop(&mut self.data.get_mut().value)
},
OnceExclusiveState::Poisoned => {}
}
}
}
#[stable(feature = "lazy_cell", since = "1.80.0")]
impl<T, F: FnOnce() -> T> Deref for LazyLock<T, F> {
type Target = T;
/// Dereferences the value.
///
/// This method will block the calling thread if another initialization
/// routine is currently running.
///
/// # Panics
///
/// If the initialization closure panics (the one that is passed to the [`new()`] method), the
/// panic is propagated to the caller, and the lock becomes poisoned. This will cause all future
/// accesses of the lock (via [`force()`] or a dereference) to panic.
///
/// [`new()`]: LazyLock::new
/// [`force()`]: LazyLock::force
#[inline]
fn deref(&self) -> &T {
LazyLock::force(self)
}
}
#[stable(feature = "lazy_deref_mut", since = "1.89.0")]
impl<T, F: FnOnce() -> T> DerefMut for LazyLock<T, F> {
/// # Panics
///
/// If the initialization closure panics (the one that is passed to the [`new()`] method), the
/// panic is propagated to the caller, and the lock becomes poisoned. This will cause all future
/// accesses of the lock (via [`force()`] or a dereference) to panic.
///
/// [`new()`]: LazyLock::new
/// [`force()`]: LazyLock::force
#[inline]
fn deref_mut(&mut self) -> &mut T {
LazyLock::force_mut(self)
}
}
#[stable(feature = "lazy_cell", since = "1.80.0")]
impl<T: Default> Default for LazyLock<T> {
/// Creates a new lazy value using `Default` as the initializing function.
#[inline]
fn default() -> LazyLock<T> {
LazyLock::new(T::default)
}
}
#[stable(feature = "lazy_cell", since = "1.80.0")]
impl<T: fmt::Debug, F> fmt::Debug for LazyLock<T, F> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut d = f.debug_tuple("LazyLock");
match LazyLock::get(self) {
Some(v) => d.field(v),
None => d.field(&format_args!("<uninit>")),
};
d.finish()
}
}
#[cold]
#[inline(never)]
fn panic_poisoned() -> ! {
panic!("LazyLock instance has previously been poisoned")
}
// We never create a `&F` from a `&LazyLock<T, F>` so it is fine
// to not impl `Sync` for `F`.
#[stable(feature = "lazy_cell", since = "1.80.0")]
unsafe impl<T: Sync + Send, F: Send> Sync for LazyLock<T, F> {}
// auto-derived `Send` impl is OK.
#[stable(feature = "lazy_cell", since = "1.80.0")]
impl<T: RefUnwindSafe + UnwindSafe, F: UnwindSafe> RefUnwindSafe for LazyLock<T, F> {}
#[stable(feature = "lazy_cell", since = "1.80.0")]
impl<T: UnwindSafe, F: UnwindSafe> UnwindSafe for LazyLock<T, F> {}

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//! Bounded channel based on a preallocated array.
//!
//! This flavor has a fixed, positive capacity.
//!
//! The implementation is based on Dmitry Vyukov's bounded MPMC queue.
//!
//! Source:
//! - <http://www.1024cores.net/home/lock-free-algorithms/queues/bounded-mpmc-queue>
//! - <https://docs.google.com/document/d/1yIAYmbvL3JxOKOjuCyon7JhW4cSv1wy5hC0ApeGMV9s/pub>
use super::context::Context;
use super::error::*;
use super::select::{Operation, Selected, Token};
use super::utils::{Backoff, CachePadded};
use super::waker::SyncWaker;
use crate::cell::UnsafeCell;
use crate::mem::MaybeUninit;
use crate::ptr;
use crate::sync::atomic::{self, Atomic, AtomicUsize, Ordering};
use crate::time::Instant;
/// A slot in a channel.
struct Slot<T> {
/// The current stamp.
stamp: Atomic<usize>,
/// The message in this slot. Either read out in `read` or dropped through
/// `discard_all_messages`.
msg: UnsafeCell<MaybeUninit<T>>,
}
/// The token type for the array flavor.
#[derive(Debug)]
pub(crate) struct ArrayToken {
/// Slot to read from or write to.
slot: *const u8,
/// Stamp to store into the slot after reading or writing.
stamp: usize,
}
impl Default for ArrayToken {
#[inline]
fn default() -> Self {
ArrayToken { slot: ptr::null(), stamp: 0 }
}
}
/// Bounded channel based on a preallocated array.
pub(crate) struct Channel<T> {
/// The head of the channel.
///
/// This value is a "stamp" consisting of an index into the buffer, a mark bit, and a lap, but
/// packed into a single `usize`. The lower bits represent the index, while the upper bits
/// represent the lap. The mark bit in the head is always zero.
///
/// Messages are popped from the head of the channel.
head: CachePadded<Atomic<usize>>,
/// The tail of the channel.
///
/// This value is a "stamp" consisting of an index into the buffer, a mark bit, and a lap, but
/// packed into a single `usize`. The lower bits represent the index, while the upper bits
/// represent the lap. The mark bit indicates that the channel is disconnected.
///
/// Messages are pushed into the tail of the channel.
tail: CachePadded<Atomic<usize>>,
/// The buffer holding slots.
buffer: Box<[Slot<T>]>,
/// The channel capacity.
cap: usize,
/// A stamp with the value of `{ lap: 1, mark: 0, index: 0 }`.
one_lap: usize,
/// If this bit is set in the tail, that means the channel is disconnected.
mark_bit: usize,
/// Senders waiting while the channel is full.
senders: SyncWaker,
/// Receivers waiting while the channel is empty and not disconnected.
receivers: SyncWaker,
}
impl<T> Channel<T> {
/// Creates a bounded channel of capacity `cap`.
pub(crate) fn with_capacity(cap: usize) -> Self {
assert!(cap > 0, "capacity must be positive");
// Compute constants `mark_bit` and `one_lap`.
let mark_bit = (cap + 1).next_power_of_two();
let one_lap = mark_bit * 2;
// Head is initialized to `{ lap: 0, mark: 0, index: 0 }`.
let head = 0;
// Tail is initialized to `{ lap: 0, mark: 0, index: 0 }`.
let tail = 0;
// Allocate a buffer of `cap` slots initialized
// with stamps.
let buffer: Box<[Slot<T>]> = (0..cap)
.map(|i| {
// Set the stamp to `{ lap: 0, mark: 0, index: i }`.
Slot { stamp: AtomicUsize::new(i), msg: UnsafeCell::new(MaybeUninit::uninit()) }
})
.collect();
Channel {
buffer,
cap,
one_lap,
mark_bit,
head: CachePadded::new(AtomicUsize::new(head)),
tail: CachePadded::new(AtomicUsize::new(tail)),
senders: SyncWaker::new(),
receivers: SyncWaker::new(),
}
}
/// Attempts to reserve a slot for sending a message.
fn start_send(&self, token: &mut Token) -> bool {
let backoff = Backoff::new();
let mut tail = self.tail.load(Ordering::Relaxed);
loop {
// Check if the channel is disconnected.
if tail & self.mark_bit != 0 {
token.array.slot = ptr::null();
token.array.stamp = 0;
return true;
}
// Deconstruct the tail.
let index = tail & (self.mark_bit - 1);
let lap = tail & !(self.one_lap - 1);
// Inspect the corresponding slot.
debug_assert!(index < self.buffer.len());
let slot = unsafe { self.buffer.get_unchecked(index) };
let stamp = slot.stamp.load(Ordering::Acquire);
// If the tail and the stamp match, we may attempt to push.
if tail == stamp {
let new_tail = if index + 1 < self.cap {
// Same lap, incremented index.
// Set to `{ lap: lap, mark: 0, index: index + 1 }`.
tail + 1
} else {
// One lap forward, index wraps around to zero.
// Set to `{ lap: lap.wrapping_add(1), mark: 0, index: 0 }`.
lap.wrapping_add(self.one_lap)
};
// Try moving the tail.
match self.tail.compare_exchange_weak(
tail,
new_tail,
Ordering::SeqCst,
Ordering::Relaxed,
) {
Ok(_) => {
// Prepare the token for the follow-up call to `write`.
token.array.slot = slot as *const Slot<T> as *const u8;
token.array.stamp = tail + 1;
return true;
}
Err(_) => {
backoff.spin_light();
tail = self.tail.load(Ordering::Relaxed);
}
}
} else if stamp.wrapping_add(self.one_lap) == tail + 1 {
atomic::fence(Ordering::SeqCst);
let head = self.head.load(Ordering::Relaxed);
// If the head lags one lap behind the tail as well...
if head.wrapping_add(self.one_lap) == tail {
// ...then the channel is full.
return false;
}
backoff.spin_light();
tail = self.tail.load(Ordering::Relaxed);
} else {
// Snooze because we need to wait for the stamp to get updated.
backoff.spin_heavy();
tail = self.tail.load(Ordering::Relaxed);
}
}
}
/// Writes a message into the channel.
pub(crate) unsafe fn write(&self, token: &mut Token, msg: T) -> Result<(), T> {
// If there is no slot, the channel is disconnected.
if token.array.slot.is_null() {
return Err(msg);
}
// Write the message into the slot and update the stamp.
unsafe {
let slot: &Slot<T> = &*(token.array.slot as *const Slot<T>);
slot.msg.get().write(MaybeUninit::new(msg));
slot.stamp.store(token.array.stamp, Ordering::Release);
}
// Wake a sleeping receiver.
self.receivers.notify();
Ok(())
}
/// Attempts to reserve a slot for receiving a message.
fn start_recv(&self, token: &mut Token) -> bool {
let backoff = Backoff::new();
let mut head = self.head.load(Ordering::Relaxed);
loop {
// Deconstruct the head.
let index = head & (self.mark_bit - 1);
let lap = head & !(self.one_lap - 1);
// Inspect the corresponding slot.
debug_assert!(index < self.buffer.len());
let slot = unsafe { self.buffer.get_unchecked(index) };
let stamp = slot.stamp.load(Ordering::Acquire);
// If the stamp is ahead of the head by 1, we may attempt to pop.
if head + 1 == stamp {
let new = if index + 1 < self.cap {
// Same lap, incremented index.
// Set to `{ lap: lap, mark: 0, index: index + 1 }`.
head + 1
} else {
// One lap forward, index wraps around to zero.
// Set to `{ lap: lap.wrapping_add(1), mark: 0, index: 0 }`.
lap.wrapping_add(self.one_lap)
};
// Try moving the head.
match self.head.compare_exchange_weak(
head,
new,
Ordering::SeqCst,
Ordering::Relaxed,
) {
Ok(_) => {
// Prepare the token for the follow-up call to `read`.
token.array.slot = slot as *const Slot<T> as *const u8;
token.array.stamp = head.wrapping_add(self.one_lap);
return true;
}
Err(_) => {
backoff.spin_light();
head = self.head.load(Ordering::Relaxed);
}
}
} else if stamp == head {
atomic::fence(Ordering::SeqCst);
let tail = self.tail.load(Ordering::Relaxed);
// If the tail equals the head, that means the channel is empty.
if (tail & !self.mark_bit) == head {
// If the channel is disconnected...
if tail & self.mark_bit != 0 {
// ...then receive an error.
token.array.slot = ptr::null();
token.array.stamp = 0;
return true;
} else {
// Otherwise, the receive operation is not ready.
return false;
}
}
backoff.spin_light();
head = self.head.load(Ordering::Relaxed);
} else {
// Snooze because we need to wait for the stamp to get updated.
backoff.spin_heavy();
head = self.head.load(Ordering::Relaxed);
}
}
}
/// Reads a message from the channel.
pub(crate) unsafe fn read(&self, token: &mut Token) -> Result<T, ()> {
if token.array.slot.is_null() {
// The channel is disconnected.
return Err(());
}
// Read the message from the slot and update the stamp.
let msg = unsafe {
let slot: &Slot<T> = &*(token.array.slot as *const Slot<T>);
let msg = slot.msg.get().read().assume_init();
slot.stamp.store(token.array.stamp, Ordering::Release);
msg
};
// Wake a sleeping sender.
self.senders.notify();
Ok(msg)
}
/// Attempts to send a message into the channel.
pub(crate) fn try_send(&self, msg: T) -> Result<(), TrySendError<T>> {
let token = &mut Token::default();
if self.start_send(token) {
unsafe { self.write(token, msg).map_err(TrySendError::Disconnected) }
} else {
Err(TrySendError::Full(msg))
}
}
/// Sends a message into the channel.
pub(crate) fn send(
&self,
msg: T,
deadline: Option<Instant>,
) -> Result<(), SendTimeoutError<T>> {
let token = &mut Token::default();
loop {
// Try sending a message.
if self.start_send(token) {
let res = unsafe { self.write(token, msg) };
return res.map_err(SendTimeoutError::Disconnected);
}
if let Some(d) = deadline {
if Instant::now() >= d {
return Err(SendTimeoutError::Timeout(msg));
}
}
Context::with(|cx| {
// Prepare for blocking until a receiver wakes us up.
let oper = Operation::hook(token);
self.senders.register(oper, cx);
// Has the channel become ready just now?
if !self.is_full() || self.is_disconnected() {
let _ = cx.try_select(Selected::Aborted);
}
// Block the current thread.
// SAFETY: the context belongs to the current thread.
let sel = unsafe { cx.wait_until(deadline) };
match sel {
Selected::Waiting => unreachable!(),
Selected::Aborted | Selected::Disconnected => {
self.senders.unregister(oper).unwrap();
}
Selected::Operation(_) => {}
}
});
}
}
/// Attempts to receive a message without blocking.
pub(crate) fn try_recv(&self) -> Result<T, TryRecvError> {
let token = &mut Token::default();
if self.start_recv(token) {
unsafe { self.read(token).map_err(|_| TryRecvError::Disconnected) }
} else {
Err(TryRecvError::Empty)
}
}
/// Receives a message from the channel.
pub(crate) fn recv(&self, deadline: Option<Instant>) -> Result<T, RecvTimeoutError> {
let token = &mut Token::default();
loop {
// Try receiving a message.
if self.start_recv(token) {
let res = unsafe { self.read(token) };
return res.map_err(|_| RecvTimeoutError::Disconnected);
}
if let Some(d) = deadline {
if Instant::now() >= d {
return Err(RecvTimeoutError::Timeout);
}
}
Context::with(|cx| {
// Prepare for blocking until a sender wakes us up.
let oper = Operation::hook(token);
self.receivers.register(oper, cx);
// Has the channel become ready just now?
if !self.is_empty() || self.is_disconnected() {
let _ = cx.try_select(Selected::Aborted);
}
// Block the current thread.
// SAFETY: the context belongs to the current thread.
let sel = unsafe { cx.wait_until(deadline) };
match sel {
Selected::Waiting => unreachable!(),
Selected::Aborted | Selected::Disconnected => {
self.receivers.unregister(oper).unwrap();
// If the channel was disconnected, we still have to check for remaining
// messages.
}
Selected::Operation(_) => {}
}
});
}
}
/// Returns the current number of messages inside the channel.
pub(crate) fn len(&self) -> usize {
loop {
// Load the tail, then load the head.
let tail = self.tail.load(Ordering::SeqCst);
let head = self.head.load(Ordering::SeqCst);
// If the tail didn't change, we've got consistent values to work with.
if self.tail.load(Ordering::SeqCst) == tail {
let hix = head & (self.mark_bit - 1);
let tix = tail & (self.mark_bit - 1);
return if hix < tix {
tix - hix
} else if hix > tix {
self.cap - hix + tix
} else if (tail & !self.mark_bit) == head {
0
} else {
self.cap
};
}
}
}
/// Returns the capacity of the channel.
#[allow(clippy::unnecessary_wraps)] // This is intentional.
pub(crate) fn capacity(&self) -> Option<usize> {
Some(self.cap)
}
/// Disconnects senders and wakes up all blocked receivers.
///
/// Returns `true` if this call disconnected the channel.
pub(crate) fn disconnect_senders(&self) -> bool {
let tail = self.tail.fetch_or(self.mark_bit, Ordering::SeqCst);
if tail & self.mark_bit == 0 {
self.receivers.disconnect();
true
} else {
false
}
}
/// Disconnects receivers and wakes up all blocked senders.
///
/// Returns `true` if this call disconnected the channel.
///
/// # Safety
/// May only be called once upon dropping the last receiver. The
/// destruction of all other receivers must have been observed with acquire
/// ordering or stronger.
pub(crate) unsafe fn disconnect_receivers(&self) -> bool {
let tail = self.tail.fetch_or(self.mark_bit, Ordering::SeqCst);
let disconnected = if tail & self.mark_bit == 0 {
self.senders.disconnect();
true
} else {
false
};
unsafe { self.discard_all_messages(tail) };
disconnected
}
/// Discards all messages.
///
/// `tail` should be the current (and therefore last) value of `tail`.
///
/// # Panicking
/// If a destructor panics, the remaining messages are leaked, matching the
/// behavior of the unbounded channel.
///
/// # Safety
/// This method must only be called when dropping the last receiver. The
/// destruction of all other receivers must have been observed with acquire
/// ordering or stronger.
unsafe fn discard_all_messages(&self, tail: usize) {
debug_assert!(self.is_disconnected());
// Only receivers modify `head`, so since we are the last one,
// this value will not change and will not be observed (since
// no new messages can be sent after disconnection).
let mut head = self.head.load(Ordering::Relaxed);
let tail = tail & !self.mark_bit;
let backoff = Backoff::new();
loop {
// Deconstruct the head.
let index = head & (self.mark_bit - 1);
let lap = head & !(self.one_lap - 1);
// Inspect the corresponding slot.
debug_assert!(index < self.buffer.len());
let slot = unsafe { self.buffer.get_unchecked(index) };
let stamp = slot.stamp.load(Ordering::Acquire);
// If the stamp is ahead of the head by 1, we may drop the message.
if head + 1 == stamp {
head = if index + 1 < self.cap {
// Same lap, incremented index.
// Set to `{ lap: lap, mark: 0, index: index + 1 }`.
head + 1
} else {
// One lap forward, index wraps around to zero.
// Set to `{ lap: lap.wrapping_add(1), mark: 0, index: 0 }`.
lap.wrapping_add(self.one_lap)
};
unsafe {
(*slot.msg.get()).assume_init_drop();
}
// If the tail equals the head, that means the channel is empty.
} else if tail == head {
return;
// Otherwise, a sender is about to write into the slot, so we need
// to wait for it to update the stamp.
} else {
backoff.spin_heavy();
}
}
}
/// Returns `true` if the channel is disconnected.
pub(crate) fn is_disconnected(&self) -> bool {
self.tail.load(Ordering::SeqCst) & self.mark_bit != 0
}
/// Returns `true` if the channel is empty.
pub(crate) fn is_empty(&self) -> bool {
let head = self.head.load(Ordering::SeqCst);
let tail = self.tail.load(Ordering::SeqCst);
// Is the tail equal to the head?
//
// Note: If the head changes just before we load the tail, that means there was a moment
// when the channel was not empty, so it is safe to just return `false`.
(tail & !self.mark_bit) == head
}
/// Returns `true` if the channel is full.
pub(crate) fn is_full(&self) -> bool {
let tail = self.tail.load(Ordering::SeqCst);
let head = self.head.load(Ordering::SeqCst);
// Is the head lagging one lap behind tail?
//
// Note: If the tail changes just before we load the head, that means there was a moment
// when the channel was not full, so it is safe to just return `false`.
head.wrapping_add(self.one_lap) == tail & !self.mark_bit
}
}

159
crates/std/src/sync/mpmc/context.rs Normal file
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//! Thread-local channel context.
use super::select::Selected;
use super::waker::current_thread_id;
use crate::cell::Cell;
use crate::ptr;
use alloc_crate::sync::Arc;
use crate::sync::atomic::{Atomic, AtomicPtr, AtomicUsize, Ordering};
use crate::thread::{self, Thread};
use crate::time::Instant;
/// Thread-local context.
#[derive(Debug, Clone)]
pub struct Context {
inner: Arc<Inner>,
}
/// Inner representation of `Context`.
#[derive(Debug)]
struct Inner {
/// Selected operation.
select: Atomic<usize>,
/// A slot into which another thread may store a pointer to its `Packet`.
packet: Atomic<*mut ()>,
/// Thread handle.
thread: Thread,
/// Thread id.
thread_id: usize,
}
impl Context {
/// Creates a new context for the duration of the closure.
#[inline]
pub fn with<F, R>(f: F) -> R
where
F: FnOnce(&Context) -> R,
{
thread_local! {
/// Cached thread-local context.
static CONTEXT: Cell<Option<Context>> = Cell::new(Some(Context::new()));
}
let mut f = Some(f);
let mut f = |cx: &Context| -> R {
let f = f.take().unwrap();
f(cx)
};
CONTEXT
.try_with(|cell| match cell.take() {
None => f(&Context::new()),
Some(cx) => {
cx.reset();
let res = f(&cx);
cell.set(Some(cx));
res
}
})
.unwrap_or_else(|_| f(&Context::new()))
}
/// Creates a new `Context`.
#[cold]
fn new() -> Context {
Context {
inner: Arc::new(Inner {
select: AtomicUsize::new(Selected::Waiting.into()),
packet: AtomicPtr::new(ptr::null_mut()),
thread: thread::current_or_unnamed(),
thread_id: current_thread_id(),
}),
}
}
/// Resets `select` and `packet`.
#[inline]
fn reset(&self) {
self.inner.select.store(Selected::Waiting.into(), Ordering::Release);
self.inner.packet.store(ptr::null_mut(), Ordering::Release);
}
/// Attempts to select an operation.
///
/// On failure, the previously selected operation is returned.
#[inline]
pub fn try_select(&self, select: Selected) -> Result<(), Selected> {
self.inner
.select
.compare_exchange(
Selected::Waiting.into(),
select.into(),
Ordering::AcqRel,
Ordering::Acquire,
)
.map(|_| ())
.map_err(|e| e.into())
}
/// Stores a packet.
///
/// This method must be called after `try_select` succeeds and there is a packet to provide.
#[inline]
pub fn store_packet(&self, packet: *mut ()) {
if !packet.is_null() {
self.inner.packet.store(packet, Ordering::Release);
}
}
/// Waits until an operation is selected and returns it.
///
/// If the deadline is reached, `Selected::Aborted` will be selected.
///
/// # Safety
/// This may only be called from the thread this `Context` belongs to.
#[inline]
pub unsafe fn wait_until(&self, deadline: Option<Instant>) -> Selected {
loop {
// Check whether an operation has been selected.
let sel = Selected::from(self.inner.select.load(Ordering::Acquire));
if sel != Selected::Waiting {
return sel;
}
// If there's a deadline, park the current thread until the deadline is reached.
if let Some(end) = deadline {
let now = Instant::now();
if now < end {
// SAFETY: guaranteed by caller.
unsafe { self.inner.thread.park_timeout(end - now) };
} else {
// The deadline has been reached. Try aborting select.
return match self.try_select(Selected::Aborted) {
Ok(()) => Selected::Aborted,
Err(s) => s,
};
}
} else {
// SAFETY: guaranteed by caller.
unsafe { self.inner.thread.park() };
}
}
}
/// Unparks the thread this context belongs to.
#[inline]
pub fn unpark(&self) {
self.inner.thread.unpark();
}
/// Returns the id of the thread this context belongs to.
#[inline]
pub fn thread_id(&self) -> usize {
self.inner.thread_id
}
}

136
crates/std/src/sync/mpmc/counter.rs Normal file
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use crate::sync::atomic::{Atomic, AtomicBool, AtomicUsize, Ordering};
use crate::{ops, process};
/// Reference counter internals.
struct Counter<C> {
/// The number of senders associated with the channel.
senders: Atomic<usize>,
/// The number of receivers associated with the channel.
receivers: Atomic<usize>,
/// Set to `true` if the last sender or the last receiver reference deallocates the channel.
destroy: Atomic<bool>,
/// The internal channel.
chan: C,
}
/// Wraps a channel into the reference counter.
pub(crate) fn new<C>(chan: C) -> (Sender<C>, Receiver<C>) {
let counter = Box::into_raw(Box::new(Counter {
senders: AtomicUsize::new(1),
receivers: AtomicUsize::new(1),
destroy: AtomicBool::new(false),
chan,
}));
let s = Sender { counter };
let r = Receiver { counter };
(s, r)
}
/// The sending side.
pub(crate) struct Sender<C> {
counter: *mut Counter<C>,
}
impl<C> Sender<C> {
/// Returns the internal `Counter`.
fn counter(&self) -> &Counter<C> {
unsafe { &*self.counter }
}
/// Acquires another sender reference.
pub(crate) fn acquire(&self) -> Sender<C> {
let count = self.counter().senders.fetch_add(1, Ordering::Relaxed);
// Cloning senders and calling `mem::forget` on the clones could potentially overflow the
// counter. It's very difficult to recover sensibly from such degenerate scenarios so we
// just abort when the count becomes very large.
if count > isize::MAX as usize {
process::abort();
}
Sender { counter: self.counter }
}
/// Releases the sender reference.
///
/// Function `disconnect` will be called if this is the last sender reference.
pub(crate) unsafe fn release<F: FnOnce(&C) -> bool>(&self, disconnect: F) {
if self.counter().senders.fetch_sub(1, Ordering::AcqRel) == 1 {
disconnect(&self.counter().chan);
if self.counter().destroy.swap(true, Ordering::AcqRel) {
drop(unsafe { Box::from_raw(self.counter) });
}
}
}
}
impl<C> ops::Deref for Sender<C> {
type Target = C;
fn deref(&self) -> &C {
&self.counter().chan
}
}
impl<C> PartialEq for Sender<C> {
fn eq(&self, other: &Sender<C>) -> bool {
self.counter == other.counter
}
}
/// The receiving side.
pub(crate) struct Receiver<C> {
counter: *mut Counter<C>,
}
impl<C> Receiver<C> {
/// Returns the internal `Counter`.
fn counter(&self) -> &Counter<C> {
unsafe { &*self.counter }
}
/// Acquires another receiver reference.
pub(crate) fn acquire(&self) -> Receiver<C> {
let count = self.counter().receivers.fetch_add(1, Ordering::Relaxed);
// Cloning receivers and calling `mem::forget` on the clones could potentially overflow the
// counter. It's very difficult to recover sensibly from such degenerate scenarios so we
// just abort when the count becomes very large.
if count > isize::MAX as usize {
process::abort();
}
Receiver { counter: self.counter }
}
/// Releases the receiver reference.
///
/// Function `disconnect` will be called if this is the last receiver reference.
pub(crate) unsafe fn release<F: FnOnce(&C) -> bool>(&self, disconnect: F) {
if self.counter().receivers.fetch_sub(1, Ordering::AcqRel) == 1 {
disconnect(&self.counter().chan);
if self.counter().destroy.swap(true, Ordering::AcqRel) {
drop(unsafe { Box::from_raw(self.counter) });
}
}
}
}
impl<C> ops::Deref for Receiver<C> {
type Target = C;
fn deref(&self) -> &C {
&self.counter().chan
}
}
impl<C> PartialEq for Receiver<C> {
fn eq(&self, other: &Receiver<C>) -> bool {
self.counter == other.counter
}
}

49
crates/std/src/sync/mpmc/error.rs Normal file
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pub use crate::sync::mpsc::{RecvError, RecvTimeoutError, SendError, TryRecvError, TrySendError};
use crate::{error, fmt};
/// An error returned from the [`send_timeout`] method.
///
/// The error contains the message being sent so it can be recovered.
///
/// [`send_timeout`]: super::Sender::send_timeout
#[derive(PartialEq, Eq, Clone, Copy)]
#[unstable(feature = "mpmc_channel", issue = "126840")]
pub enum SendTimeoutError<T> {
/// The message could not be sent because the channel is full and the operation timed out.
///
/// If this is a zero-capacity channel, then the error indicates that there was no receiver
/// available to receive the message and the operation timed out.
Timeout(T),
/// The message could not be sent because the channel is disconnected.
Disconnected(T),
}
#[unstable(feature = "mpmc_channel", issue = "126840")]
impl<T> fmt::Debug for SendTimeoutError<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
"SendTimeoutError(..)".fmt(f)
}
}
#[unstable(feature = "mpmc_channel", issue = "126840")]
impl<T> fmt::Display for SendTimeoutError<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match *self {
SendTimeoutError::Timeout(..) => "timed out waiting on send operation".fmt(f),
SendTimeoutError::Disconnected(..) => "sending on a disconnected channel".fmt(f),
}
}
}
#[unstable(feature = "mpmc_channel", issue = "126840")]
impl<T> error::Error for SendTimeoutError<T> {}
#[unstable(feature = "mpmc_channel", issue = "126840")]
impl<T> From<SendError<T>> for SendTimeoutError<T> {
fn from(err: SendError<T>) -> SendTimeoutError<T> {
match err {
SendError(e) => SendTimeoutError::Disconnected(e),
}
}
}

668
crates/std/src/sync/mpmc/list.rs Normal file
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//! Unbounded channel implemented as a linked list.
use super::context::Context;
use super::error::*;
use super::select::{Operation, Selected, Token};
use super::utils::{Backoff, CachePadded};
use super::waker::SyncWaker;
use crate::cell::UnsafeCell;
use crate::marker::PhantomData;
use crate::mem::MaybeUninit;
use crate::ptr;
use crate::sync::atomic::{self, Atomic, AtomicPtr, AtomicUsize, Ordering};
use crate::time::Instant;
// Bits indicating the state of a slot:
// * If a message has been written into the slot, `WRITE` is set.
// * If a message has been read from the slot, `READ` is set.
// * If the block is being destroyed, `DESTROY` is set.
const WRITE: usize = 1;
const READ: usize = 2;
const DESTROY: usize = 4;
// Each block covers one "lap" of indices.
const LAP: usize = 32;
// The maximum number of messages a block can hold.
const BLOCK_CAP: usize = LAP - 1;
// How many lower bits are reserved for metadata.
const SHIFT: usize = 1;
// Has two different purposes:
// * If set in head, indicates that the block is not the last one.
// * If set in tail, indicates that the channel is disconnected.
const MARK_BIT: usize = 1;
/// A slot in a block.
struct Slot<T> {
/// The message.
msg: UnsafeCell<MaybeUninit<T>>,
/// The state of the slot.
state: Atomic<usize>,
}
impl<T> Slot<T> {
/// Waits until a message is written into the slot.
fn wait_write(&self) {
let backoff = Backoff::new();
while self.state.load(Ordering::Acquire) & WRITE == 0 {
backoff.spin_heavy();
}
}
}
/// A block in a linked list.
///
/// Each block in the list can hold up to `BLOCK_CAP` messages.
struct Block<T> {
/// The next block in the linked list.
next: Atomic<*mut Block<T>>,
/// Slots for messages.
slots: [Slot<T>; BLOCK_CAP],
}
impl<T> Block<T> {
/// Creates an empty block.
fn new() -> Box<Block<T>> {
// SAFETY: This is safe because:
// [1] `Block::next` (Atomic<*mut _>) may be safely zero initialized.
// [2] `Block::slots` (Array) may be safely zero initialized because of [3, 4].
// [3] `Slot::msg` (UnsafeCell) may be safely zero initialized because it
// holds a MaybeUninit.
// [4] `Slot::state` (Atomic<usize>) may be safely zero initialized.
unsafe { Box::new_zeroed().assume_init() }
}
/// Waits until the next pointer is set.
fn wait_next(&self) -> *mut Block<T> {
let backoff = Backoff::new();
loop {
let next = self.next.load(Ordering::Acquire);
if !next.is_null() {
return next;
}
backoff.spin_heavy();
}
}
/// Sets the `DESTROY` bit in slots starting from `start` and destroys the block.
unsafe fn destroy(this: *mut Block<T>, start: usize) {
// It is not necessary to set the `DESTROY` bit in the last slot because that slot has
// begun destruction of the block.
for i in start..BLOCK_CAP - 1 {
let slot = unsafe { (*this).slots.get_unchecked(i) };
// Mark the `DESTROY` bit if a thread is still using the slot.
if slot.state.load(Ordering::Acquire) & READ == 0
&& slot.state.fetch_or(DESTROY, Ordering::AcqRel) & READ == 0
{
// If a thread is still using the slot, it will continue destruction of the block.
return;
}
}
// No thread is using the block, now it is safe to destroy it.
drop(unsafe { Box::from_raw(this) });
}
}
/// A position in a channel.
#[derive(Debug)]
struct Position<T> {
/// The index in the channel.
index: Atomic<usize>,
/// The block in the linked list.
block: Atomic<*mut Block<T>>,
}
/// The token type for the list flavor.
#[derive(Debug)]
pub(crate) struct ListToken {
/// The block of slots.
block: *const u8,
/// The offset into the block.
offset: usize,
}
impl Default for ListToken {
#[inline]
fn default() -> Self {
ListToken { block: ptr::null(), offset: 0 }
}
}
/// Unbounded channel implemented as a linked list.
///
/// Each message sent into the channel is assigned a sequence number, i.e. an index. Indices are
/// represented as numbers of type `usize` and wrap on overflow.
///
/// Consecutive messages are grouped into blocks in order to put less pressure on the allocator and
/// improve cache efficiency.
pub(crate) struct Channel<T> {
/// The head of the channel.
head: CachePadded<Position<T>>,
/// The tail of the channel.
tail: CachePadded<Position<T>>,
/// Receivers waiting while the channel is empty and not disconnected.
receivers: SyncWaker,
/// Indicates that dropping a `Channel<T>` may drop messages of type `T`.
_marker: PhantomData<T>,
}
impl<T> Channel<T> {
/// Creates a new unbounded channel.
pub(crate) fn new() -> Self {
Channel {
head: CachePadded::new(Position {
block: AtomicPtr::new(ptr::null_mut()),
index: AtomicUsize::new(0),
}),
tail: CachePadded::new(Position {
block: AtomicPtr::new(ptr::null_mut()),
index: AtomicUsize::new(0),
}),
receivers: SyncWaker::new(),
_marker: PhantomData,
}
}
/// Attempts to reserve a slot for sending a message.
fn start_send(&self, token: &mut Token) -> bool {
let backoff = Backoff::new();
let mut tail = self.tail.index.load(Ordering::Acquire);
let mut block = self.tail.block.load(Ordering::Acquire);
let mut next_block = None;
loop {
// Check if the channel is disconnected.
if tail & MARK_BIT != 0 {
token.list.block = ptr::null();
return true;
}
// Calculate the offset of the index into the block.
let offset = (tail >> SHIFT) % LAP;
// If we reached the end of the block, wait until the next one is installed.
if offset == BLOCK_CAP {
backoff.spin_heavy();
tail = self.tail.index.load(Ordering::Acquire);
block = self.tail.block.load(Ordering::Acquire);
continue;
}
// If we're going to have to install the next block, allocate it in advance in order to
// make the wait for other threads as short as possible.
if offset + 1 == BLOCK_CAP && next_block.is_none() {
next_block = Some(Block::<T>::new());
}
// If this is the first message to be sent into the channel, we need to allocate the
// first block and install it.
if block.is_null() {
let new = Box::into_raw(Block::<T>::new());
if self
.tail
.block
.compare_exchange(block, new, Ordering::Release, Ordering::Relaxed)
.is_ok()
{
// This yield point leaves the channel in a half-initialized state where the
// tail.block pointer is set but the head.block is not. This is used to
// facilitate the test in src/tools/miri/tests/pass/issues/issue-139553.rs
#[cfg(miri)]
crate::thread::yield_now();
self.head.block.store(new, Ordering::Release);
block = new;
} else {
next_block = unsafe { Some(Box::from_raw(new)) };
tail = self.tail.index.load(Ordering::Acquire);
block = self.tail.block.load(Ordering::Acquire);
continue;
}
}
let new_tail = tail + (1 << SHIFT);
// Try advancing the tail forward.
match self.tail.index.compare_exchange_weak(
tail,
new_tail,
Ordering::SeqCst,
Ordering::Acquire,
) {
Ok(_) => unsafe {
// If we've reached the end of the block, install the next one.
if offset + 1 == BLOCK_CAP {
let next_block = Box::into_raw(next_block.unwrap());
self.tail.block.store(next_block, Ordering::Release);
self.tail.index.fetch_add(1 << SHIFT, Ordering::Release);
(*block).next.store(next_block, Ordering::Release);
}
token.list.block = block as *const u8;
token.list.offset = offset;
return true;
},
Err(_) => {
backoff.spin_light();
tail = self.tail.index.load(Ordering::Acquire);
block = self.tail.block.load(Ordering::Acquire);
}
}
}
}
/// Writes a message into the channel.
pub(crate) unsafe fn write(&self, token: &mut Token, msg: T) -> Result<(), T> {
// If there is no slot, the channel is disconnected.
if token.list.block.is_null() {
return Err(msg);
}
// Write the message into the slot.
let block = token.list.block as *mut Block<T>;
let offset = token.list.offset;
unsafe {
let slot = (*block).slots.get_unchecked(offset);
slot.msg.get().write(MaybeUninit::new(msg));
slot.state.fetch_or(WRITE, Ordering::Release);
}
// Wake a sleeping receiver.
self.receivers.notify();
Ok(())
}
/// Attempts to reserve a slot for receiving a message.
fn start_recv(&self, token: &mut Token) -> bool {
let backoff = Backoff::new();
let mut head = self.head.index.load(Ordering::Acquire);
let mut block = self.head.block.load(Ordering::Acquire);
loop {
// Calculate the offset of the index into the block.
let offset = (head >> SHIFT) % LAP;
// If we reached the end of the block, wait until the next one is installed.
if offset == BLOCK_CAP {
backoff.spin_heavy();
head = self.head.index.load(Ordering::Acquire);
block = self.head.block.load(Ordering::Acquire);
continue;
}
let mut new_head = head + (1 << SHIFT);
if new_head & MARK_BIT == 0 {
atomic::fence(Ordering::SeqCst);
let tail = self.tail.index.load(Ordering::Relaxed);
// If the tail equals the head, that means the channel is empty.
if head >> SHIFT == tail >> SHIFT {
// If the channel is disconnected...
if tail & MARK_BIT != 0 {
// ...then receive an error.
token.list.block = ptr::null();
return true;
} else {
// Otherwise, the receive operation is not ready.
return false;
}
}
// If head and tail are not in the same block, set `MARK_BIT` in head.
if (head >> SHIFT) / LAP != (tail >> SHIFT) / LAP {
new_head |= MARK_BIT;
}
}
// The block can be null here only if the first message is being sent into the channel.
// In that case, just wait until it gets initialized.
if block.is_null() {
backoff.spin_heavy();
head = self.head.index.load(Ordering::Acquire);
block = self.head.block.load(Ordering::Acquire);
continue;
}
// Try moving the head index forward.
match self.head.index.compare_exchange_weak(
head,
new_head,
Ordering::SeqCst,
Ordering::Acquire,
) {
Ok(_) => unsafe {
// If we've reached the end of the block, move to the next one.
if offset + 1 == BLOCK_CAP {
let next = (*block).wait_next();
let mut next_index = (new_head & !MARK_BIT).wrapping_add(1 << SHIFT);
if !(*next).next.load(Ordering::Relaxed).is_null() {
next_index |= MARK_BIT;
}
self.head.block.store(next, Ordering::Release);
self.head.index.store(next_index, Ordering::Release);
}
token.list.block = block as *const u8;
token.list.offset = offset;
return true;
},
Err(_) => {
backoff.spin_light();
head = self.head.index.load(Ordering::Acquire);
block = self.head.block.load(Ordering::Acquire);
}
}
}
}
/// Reads a message from the channel.
pub(crate) unsafe fn read(&self, token: &mut Token) -> Result<T, ()> {
if token.list.block.is_null() {
// The channel is disconnected.
return Err(());
}
// Read the message.
let block = token.list.block as *mut Block<T>;
let offset = token.list.offset;
unsafe {
let slot = (*block).slots.get_unchecked(offset);
slot.wait_write();
let msg = slot.msg.get().read().assume_init();
// Destroy the block if we've reached the end, or if another thread wanted to destroy but
// couldn't because we were busy reading from the slot.
if offset + 1 == BLOCK_CAP {
Block::destroy(block, 0);
} else if slot.state.fetch_or(READ, Ordering::AcqRel) & DESTROY != 0 {
Block::destroy(block, offset + 1);
}
Ok(msg)
}
}
/// Attempts to send a message into the channel.
pub(crate) fn try_send(&self, msg: T) -> Result<(), TrySendError<T>> {
self.send(msg, None).map_err(|err| match err {
SendTimeoutError::Disconnected(msg) => TrySendError::Disconnected(msg),
SendTimeoutError::Timeout(_) => unreachable!(),
})
}
/// Sends a message into the channel.
pub(crate) fn send(
&self,
msg: T,
_deadline: Option<Instant>,
) -> Result<(), SendTimeoutError<T>> {
let token = &mut Token::default();
assert!(self.start_send(token));
unsafe { self.write(token, msg).map_err(SendTimeoutError::Disconnected) }
}
/// Attempts to receive a message without blocking.
pub(crate) fn try_recv(&self) -> Result<T, TryRecvError> {
let token = &mut Token::default();
if self.start_recv(token) {
unsafe { self.read(token).map_err(|_| TryRecvError::Disconnected) }
} else {
Err(TryRecvError::Empty)
}
}
/// Receives a message from the channel.
pub(crate) fn recv(&self, deadline: Option<Instant>) -> Result<T, RecvTimeoutError> {
let token = &mut Token::default();
loop {
if self.start_recv(token) {
unsafe {
return self.read(token).map_err(|_| RecvTimeoutError::Disconnected);
}
}
if let Some(d) = deadline {
if Instant::now() >= d {
return Err(RecvTimeoutError::Timeout);
}
}
// Prepare for blocking until a sender wakes us up.
Context::with(|cx| {
let oper = Operation::hook(token);
self.receivers.register(oper, cx);
// Has the channel become ready just now?
if !self.is_empty() || self.is_disconnected() {
let _ = cx.try_select(Selected::Aborted);
}
// Block the current thread.
// SAFETY: the context belongs to the current thread.
let sel = unsafe { cx.wait_until(deadline) };
match sel {
Selected::Waiting => unreachable!(),
Selected::Aborted | Selected::Disconnected => {
self.receivers.unregister(oper).unwrap();
// If the channel was disconnected, we still have to check for remaining
// messages.
}
Selected::Operation(_) => {}
}
});
}
}
/// Returns the current number of messages inside the channel.
pub(crate) fn len(&self) -> usize {
loop {
// Load the tail index, then load the head index.
let mut tail = self.tail.index.load(Ordering::SeqCst);
let mut head = self.head.index.load(Ordering::SeqCst);
// If the tail index didn't change, we've got consistent indices to work with.
if self.tail.index.load(Ordering::SeqCst) == tail {
// Erase the lower bits.
tail &= !((1 << SHIFT) - 1);
head &= !((1 << SHIFT) - 1);
// Fix up indices if they fall onto block ends.
if (tail >> SHIFT) & (LAP - 1) == LAP - 1 {
tail = tail.wrapping_add(1 << SHIFT);
}
if (head >> SHIFT) & (LAP - 1) == LAP - 1 {
head = head.wrapping_add(1 << SHIFT);
}
// Rotate indices so that head falls into the first block.
let lap = (head >> SHIFT) / LAP;
tail = tail.wrapping_sub((lap * LAP) << SHIFT);
head = head.wrapping_sub((lap * LAP) << SHIFT);
// Remove the lower bits.
tail >>= SHIFT;
head >>= SHIFT;
// Return the difference minus the number of blocks between tail and head.
return tail - head - tail / LAP;
}
}
}
/// Returns the capacity of the channel.
pub(crate) fn capacity(&self) -> Option<usize> {
None
}
/// Disconnects senders and wakes up all blocked receivers.
///
/// Returns `true` if this call disconnected the channel.
pub(crate) fn disconnect_senders(&self) -> bool {
let tail = self.tail.index.fetch_or(MARK_BIT, Ordering::SeqCst);
if tail & MARK_BIT == 0 {
self.receivers.disconnect();
true
} else {
false
}
}
/// Disconnects receivers.
///
/// Returns `true` if this call disconnected the channel.
pub(crate) fn disconnect_receivers(&self) -> bool {
let tail = self.tail.index.fetch_or(MARK_BIT, Ordering::SeqCst);
if tail & MARK_BIT == 0 {
// If receivers are dropped first, discard all messages to free
// memory eagerly.
self.discard_all_messages();
true
} else {
false
}
}
/// Discards all messages.
///
/// This method should only be called when all receivers are dropped.
fn discard_all_messages(&self) {
let backoff = Backoff::new();
let mut tail = self.tail.index.load(Ordering::Acquire);
loop {
let offset = (tail >> SHIFT) % LAP;
if offset != BLOCK_CAP {
break;
}
// New updates to tail will be rejected by MARK_BIT and aborted unless it's
// at boundary. We need to wait for the updates take affect otherwise there
// can be memory leaks.
backoff.spin_heavy();
tail = self.tail.index.load(Ordering::Acquire);
}
let mut head = self.head.index.load(Ordering::Acquire);
// The channel may be uninitialized, so we have to swap to avoid overwriting any sender's attempts
// to initialize the first block before noticing that the receivers disconnected. Late allocations
// will be deallocated by the sender in Drop.
let mut block = self.head.block.swap(ptr::null_mut(), Ordering::AcqRel);
// If we're going to be dropping messages we need to synchronize with initialization
if head >> SHIFT != tail >> SHIFT {
// The block can be null here only if a sender is in the process of initializing the
// channel while another sender managed to send a message by inserting it into the
// semi-initialized channel and advanced the tail.
// In that case, just wait until it gets initialized.
while block.is_null() {
backoff.spin_heavy();
block = self.head.block.swap(ptr::null_mut(), Ordering::AcqRel);
}
}
// After this point `head.block` is not modified again and it will be deallocated if it's
// non-null. The `Drop` code of the channel, which runs after this function, also attempts
// to deallocate `head.block` if it's non-null. Therefore this function must maintain the
// invariant that if a deallocation of head.block is attempted then it must also be set to
// NULL. Failing to do so will lead to the Drop code attempting a double free. For this
// reason both reads above do an atomic swap instead of a simple atomic load.
unsafe {
// Drop all messages between head and tail and deallocate the heap-allocated blocks.
while head >> SHIFT != tail >> SHIFT {
let offset = (head >> SHIFT) % LAP;
if offset < BLOCK_CAP {
// Drop the message in the slot.
let slot = (*block).slots.get_unchecked(offset);
slot.wait_write();
let p = &mut *slot.msg.get();
p.as_mut_ptr().drop_in_place();
} else {
(*block).wait_next();
// Deallocate the block and move to the next one.
let next = (*block).next.load(Ordering::Acquire);
drop(Box::from_raw(block));
block = next;
}
head = head.wrapping_add(1 << SHIFT);
}
// Deallocate the last remaining block.
if !block.is_null() {
drop(Box::from_raw(block));
}
}
head &= !MARK_BIT;
self.head.index.store(head, Ordering::Release);
}
/// Returns `true` if the channel is disconnected.
pub(crate) fn is_disconnected(&self) -> bool {
self.tail.index.load(Ordering::SeqCst) & MARK_BIT != 0
}
/// Returns `true` if the channel is empty.
pub(crate) fn is_empty(&self) -> bool {
let head = self.head.index.load(Ordering::SeqCst);
let tail = self.tail.index.load(Ordering::SeqCst);
head >> SHIFT == tail >> SHIFT
}
/// Returns `true` if the channel is full.
pub(crate) fn is_full(&self) -> bool {
false
}
}
impl<T> Drop for Channel<T> {
fn drop(&mut self) {
let mut head = self.head.index.load(Ordering::Relaxed);
let mut tail = self.tail.index.load(Ordering::Relaxed);
let mut block = self.head.block.load(Ordering::Relaxed);
// Erase the lower bits.
head &= !((1 << SHIFT) - 1);
tail &= !((1 << SHIFT) - 1);
unsafe {
// Drop all messages between head and tail and deallocate the heap-allocated blocks.
while head != tail {
let offset = (head >> SHIFT) % LAP;
if offset < BLOCK_CAP {
// Drop the message in the slot.
let slot = (*block).slots.get_unchecked(offset);
let p = &mut *slot.msg.get();
p.as_mut_ptr().drop_in_place();
} else {
// Deallocate the block and move to the next one.
let next = (*block).next.load(Ordering::Relaxed);
drop(Box::from_raw(block));
block = next;
}
head = head.wrapping_add(1 << SHIFT);
}
// Deallocate the last remaining block.
if !block.is_null() {
drop(Box::from_raw(block));
}
}
}
}

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crates/std/src/sync/mpmc/mod.rs Normal file
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71
crates/std/src/sync/mpmc/select.rs Normal file
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/// Temporary data that gets initialized during a blocking operation, and is consumed by
/// `read` or `write`.
///
/// Each field contains data associated with a specific channel flavor.
#[derive(Debug, Default)]
pub struct Token {
pub(crate) array: super::array::ArrayToken,
pub(crate) list: super::list::ListToken,
#[allow(dead_code)]
pub(crate) zero: super::zero::ZeroToken,
}
/// Identifier associated with an operation by a specific thread on a specific channel.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct Operation(usize);
impl Operation {
/// Creates an operation identifier from a mutable reference.
///
/// This function essentially just turns the address of the reference into a number. The
/// reference should point to a variable that is specific to the thread and the operation,
/// and is alive for the entire duration of a blocking operation.
#[inline]
pub fn hook<T>(r: &mut T) -> Operation {
let val = r as *mut T as usize;
// Make sure that the pointer address doesn't equal the numerical representation of
// `Selected::{Waiting, Aborted, Disconnected}`.
assert!(val > 2);
Operation(val)
}
}
/// Current state of a blocking operation.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Selected {
/// Still waiting for an operation.
Waiting,
/// The attempt to block the current thread has been aborted.
Aborted,
/// An operation became ready because a channel is disconnected.
Disconnected,
/// An operation became ready because a message can be sent or received.
Operation(Operation),
}
impl From<usize> for Selected {
#[inline]
fn from(val: usize) -> Selected {
match val {
0 => Selected::Waiting,
1 => Selected::Aborted,
2 => Selected::Disconnected,
oper => Selected::Operation(Operation(oper)),
}
}
}
impl Into<usize> for Selected {
#[inline]
fn into(self) -> usize {
match self {
Selected::Waiting => 0,
Selected::Aborted => 1,
Selected::Disconnected => 2,
Selected::Operation(Operation(val)) => val,
}
}
}

14
crates/std/src/sync/mpmc/tests.rs Normal file
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// Ensure that thread_local init with `const { 0 }` still has unique address at run-time
#[test]
fn waker_current_thread_id() {
let first = super::waker::current_thread_id();
let t = crate::thread::spawn(move || {
let second = super::waker::current_thread_id();
assert_ne!(first, second);
assert_eq!(second, super::waker::current_thread_id());
});
assert_eq!(first, super::waker::current_thread_id());
t.join().unwrap();
assert_eq!(first, super::waker::current_thread_id());
}

137
crates/std/src/sync/mpmc/utils.rs Normal file
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use crate::cell::Cell;
use crate::ops::{Deref, DerefMut};
/// Pads and aligns a value to the length of a cache line.
#[derive(Clone, Copy, Default, Hash, PartialEq, Eq)]
// Starting from Intel's Sandy Bridge, spatial prefetcher is now pulling pairs of 64-byte cache
// lines at a time, so we have to align to 128 bytes rather than 64.
//
// Sources:
// - https://www.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-optimization-manual.pdf
// - https://github.com/facebook/folly/blob/1b5288e6eea6df074758f877c849b6e73bbb9fbb/folly/lang/Align.h#L107
//
// ARM's big.LITTLE architecture has asymmetric cores and "big" cores have 128-byte cache line size.
//
// Sources:
// - https://www.mono-project.com/news/2016/09/12/arm64-icache/
//
// powerpc64 has 128-byte cache line size.
//
// Sources:
// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_ppc64x.go#L9
#[cfg_attr(
any(target_arch = "x86_64", target_arch = "aarch64", target_arch = "powerpc64",),
repr(align(128))
)]
// arm, mips and mips64 have 32-byte cache line size.
//
// Sources:
// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_arm.go#L7
// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_mips.go#L7
// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_mipsle.go#L7
// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_mips64x.go#L9
#[cfg_attr(
any(
target_arch = "arm",
target_arch = "mips",
target_arch = "mips32r6",
target_arch = "mips64",
target_arch = "mips64r6",
),
repr(align(32))
)]
// s390x has 256-byte cache line size.
//
// Sources:
// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_s390x.go#L7
#[cfg_attr(target_arch = "s390x", repr(align(256)))]
// x86, wasm and riscv have 64-byte cache line size.
//
// Sources:
// - https://github.com/golang/go/blob/dda2991c2ea0c5914714469c4defc2562a907230/src/internal/cpu/cpu_x86.go#L9
// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_wasm.go#L7
// - https://github.com/golang/go/blob/5e31f78c8a4ed1b872ddc194f0cd1ae931b37d7e/src/internal/cpu/cpu_riscv64.go#L7
//
// All others are assumed to have 64-byte cache line size.
#[cfg_attr(
not(any(
target_arch = "x86_64",
target_arch = "aarch64",
target_arch = "powerpc64",
target_arch = "arm",
target_arch = "mips",
target_arch = "mips32r6",
target_arch = "mips64",
target_arch = "mips64r6",
target_arch = "s390x",
)),
repr(align(64))
)]
pub struct CachePadded<T> {
value: T,
}
impl<T> CachePadded<T> {
/// Pads and aligns a value to the length of a cache line.
pub fn new(value: T) -> CachePadded<T> {
CachePadded::<T> { value }
}
}
impl<T> Deref for CachePadded<T> {
type Target = T;
fn deref(&self) -> &T {
&self.value
}
}
impl<T> DerefMut for CachePadded<T> {
fn deref_mut(&mut self) -> &mut T {
&mut self.value
}
}
const SPIN_LIMIT: u32 = 6;
/// Performs quadratic backoff in spin loops.
pub struct Backoff {
step: Cell<u32>,
}
impl Backoff {
/// Creates a new `Backoff`.
pub fn new() -> Self {
Backoff { step: Cell::new(0) }
}
/// Backs off using lightweight spinning.
///
/// This method should be used for retrying an operation because another thread made
/// progress. i.e. on CAS failure.
#[inline]
pub fn spin_light(&self) {
let step = self.step.get().min(SPIN_LIMIT);
for _ in 0..step.pow(2) {
crate::hint::spin_loop();
}
self.step.set(self.step.get() + 1);
}
/// Backs off using heavyweight spinning.
///
/// This method should be used in blocking loops where parking the thread is not an option.
#[inline]
pub fn spin_heavy(&self) {
if self.step.get() <= SPIN_LIMIT {
for _ in 0..self.step.get().pow(2) {
crate::hint::spin_loop()
}
} else {
crate::thread::yield_now();
}
self.step.set(self.step.get() + 1);
}
}

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crates/std/src/sync/mpmc/waker.rs Normal file
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//! Waking mechanism for threads blocked on channel operations.
use super::context::Context;
use super::select::{Operation, Selected};
use crate::ptr;
use crate::sync::Mutex;
use crate::sync::atomic::{Atomic, AtomicBool, Ordering};
/// Represents a thread blocked on a specific channel operation.
pub(crate) struct Entry {
/// The operation.
pub(crate) oper: Operation,
/// Optional packet.
pub(crate) packet: *mut (),
/// Context associated with the thread owning this operation.
pub(crate) cx: Context,
}
/// A queue of threads blocked on channel operations.
///
/// This data structure is used by threads to register blocking operations and get woken up once
/// an operation becomes ready.
pub(crate) struct Waker {
/// A list of select operations.
selectors: Vec<Entry>,
/// A list of operations waiting to be ready.
observers: Vec<Entry>,
}
impl Waker {
/// Creates a new `Waker`.
#[inline]
pub(crate) fn new() -> Self {
Waker { selectors: Vec::new(), observers: Vec::new() }
}
/// Registers a select operation.
#[inline]
pub(crate) fn register(&mut self, oper: Operation, cx: &Context) {
self.register_with_packet(oper, ptr::null_mut(), cx);
}
/// Registers a select operation and a packet.
#[inline]
pub(crate) fn register_with_packet(&mut self, oper: Operation, packet: *mut (), cx: &Context) {
self.selectors.push(Entry { oper, packet, cx: cx.clone() });
}
/// Unregisters a select operation.
#[inline]
pub(crate) fn unregister(&mut self, oper: Operation) -> Option<Entry> {
if let Some((i, _)) =
self.selectors.iter().enumerate().find(|&(_, entry)| entry.oper == oper)
{
let entry = self.selectors.remove(i);
Some(entry)
} else {
None
}
}
/// Attempts to find another thread's entry, select the operation, and wake it up.
#[inline]
pub(crate) fn try_select(&mut self) -> Option<Entry> {
if self.selectors.is_empty() {
None
} else {
let thread_id = current_thread_id();
self.selectors
.iter()
.position(|selector| {
// Does the entry belong to a different thread?
selector.cx.thread_id() != thread_id
&& selector // Try selecting this operation.
.cx
.try_select(Selected::Operation(selector.oper))
.is_ok()
&& {
// Provide the packet.
selector.cx.store_packet(selector.packet);
// Wake the thread up.
selector.cx.unpark();
true
}
})
// Remove the entry from the queue to keep it clean and improve
// performance.
.map(|pos| self.selectors.remove(pos))
}
}
/// Notifies all operations waiting to be ready.
#[inline]
pub(crate) fn notify(&mut self) {
for entry in self.observers.drain(..) {
if entry.cx.try_select(Selected::Operation(entry.oper)).is_ok() {
entry.cx.unpark();
}
}
}
/// Notifies all registered operations that the channel is disconnected.
#[inline]
pub(crate) fn disconnect(&mut self) {
for entry in self.selectors.iter() {
if entry.cx.try_select(Selected::Disconnected).is_ok() {
// Wake the thread up.
//
// Here we don't remove the entry from the queue. Registered threads must
// unregister from the waker by themselves. They might also want to recover the
// packet value and destroy it, if necessary.
entry.cx.unpark();
}
}
self.notify();
}
}
impl Drop for Waker {
#[inline]
fn drop(&mut self) {
debug_assert_eq!(self.selectors.len(), 0);
debug_assert_eq!(self.observers.len(), 0);
}
}
/// A waker that can be shared among threads without locking.
///
/// This is a simple wrapper around `Waker` that internally uses a mutex for synchronization.
pub(crate) struct SyncWaker {
/// The inner `Waker`.
inner: Mutex<Waker>,
/// `true` if the waker is empty.
is_empty: Atomic<bool>,
}
impl SyncWaker {
/// Creates a new `SyncWaker`.
#[inline]
pub(crate) fn new() -> Self {
SyncWaker { inner: Mutex::new(Waker::new()), is_empty: AtomicBool::new(true) }
}
/// Registers the current thread with an operation.
#[inline]
pub(crate) fn register(&self, oper: Operation, cx: &Context) {
let mut inner = self.inner.lock().unwrap();
inner.register(oper, cx);
self.is_empty
.store(inner.selectors.is_empty() && inner.observers.is_empty(), Ordering::SeqCst);
}
/// Unregisters an operation previously registered by the current thread.
#[inline]
pub(crate) fn unregister(&self, oper: Operation) -> Option<Entry> {
let mut inner = self.inner.lock().unwrap();
let entry = inner.unregister(oper);
self.is_empty
.store(inner.selectors.is_empty() && inner.observers.is_empty(), Ordering::SeqCst);
entry
}
/// Attempts to find one thread (not the current one), select its operation, and wake it up.
#[inline]
pub(crate) fn notify(&self) {
if !self.is_empty.load(Ordering::SeqCst) {
let mut inner = self.inner.lock().unwrap();
if !self.is_empty.load(Ordering::SeqCst) {
inner.try_select();
inner.notify();
self.is_empty.store(
inner.selectors.is_empty() && inner.observers.is_empty(),
Ordering::SeqCst,
);
}
}
}
/// Notifies all threads that the channel is disconnected.
#[inline]
pub(crate) fn disconnect(&self) {
let mut inner = self.inner.lock().unwrap();
inner.disconnect();
self.is_empty
.store(inner.selectors.is_empty() && inner.observers.is_empty(), Ordering::SeqCst);
}
}
impl Drop for SyncWaker {
#[inline]
fn drop(&mut self) {
debug_assert!(self.is_empty.load(Ordering::SeqCst));
}
}
/// Returns a unique id for the current thread.
#[inline]
pub fn current_thread_id() -> usize {
// `u8` is not drop so this variable will be available during thread destruction,
// whereas `thread::current()` would not be
thread_local! { static DUMMY: u8 = const { 0 } }
DUMMY.with(|x| (x as *const u8).addr())
}

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crates/std/src/sync/mpmc/zero.rs Normal file
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//! Zero-capacity channel.
//!
//! This kind of channel is also known as *rendezvous* channel.
use super::context::Context;
use super::error::*;
use super::select::{Operation, Selected, Token};
use super::utils::Backoff;
use super::waker::Waker;
use crate::cell::UnsafeCell;
use crate::marker::PhantomData;
use crate::sync::Mutex;
use crate::sync::atomic::{Atomic, AtomicBool, Ordering};
use crate::time::Instant;
use crate::{fmt, ptr};
/// A pointer to a packet.
pub(crate) struct ZeroToken(*mut ());
impl Default for ZeroToken {
fn default() -> Self {
Self(ptr::null_mut())
}
}
impl fmt::Debug for ZeroToken {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Debug::fmt(&(self.0 as usize), f)
}
}
/// A slot for passing one message from a sender to a receiver.
struct Packet<T> {
/// Equals `true` if the packet is allocated on the stack.
on_stack: bool,
/// Equals `true` once the packet is ready for reading or writing.
ready: Atomic<bool>,
/// The message.
msg: UnsafeCell<Option<T>>,
}
impl<T> Packet<T> {
/// Creates an empty packet on the stack.
fn empty_on_stack() -> Packet<T> {
Packet { on_stack: true, ready: AtomicBool::new(false), msg: UnsafeCell::new(None) }
}
/// Creates a packet on the stack, containing a message.
fn message_on_stack(msg: T) -> Packet<T> {
Packet { on_stack: true, ready: AtomicBool::new(false), msg: UnsafeCell::new(Some(msg)) }
}
/// Waits until the packet becomes ready for reading or writing.
fn wait_ready(&self) {
let backoff = Backoff::new();
while !self.ready.load(Ordering::Acquire) {
backoff.spin_heavy();
}
}
}
/// Inner representation of a zero-capacity channel.
struct Inner {
/// Senders waiting to pair up with a receive operation.
senders: Waker,
/// Receivers waiting to pair up with a send operation.
receivers: Waker,
/// Equals `true` when the channel is disconnected.
is_disconnected: bool,
}
/// Zero-capacity channel.
pub(crate) struct Channel<T> {
/// Inner representation of the channel.
inner: Mutex<Inner>,
/// Indicates that dropping a `Channel<T>` may drop values of type `T`.
_marker: PhantomData<T>,
}
impl<T> Channel<T> {
/// Constructs a new zero-capacity channel.
pub(crate) fn new() -> Self {
Channel {
inner: Mutex::new(Inner {
senders: Waker::new(),
receivers: Waker::new(),
is_disconnected: false,
}),
_marker: PhantomData,
}
}
/// Writes a message into the packet.
pub(crate) unsafe fn write(&self, token: &mut Token, msg: T) -> Result<(), T> {
// If there is no packet, the channel is disconnected.
if token.zero.0.is_null() {
return Err(msg);
}
unsafe {
let packet = &*(token.zero.0 as *const Packet<T>);
packet.msg.get().write(Some(msg));
packet.ready.store(true, Ordering::Release);
}
Ok(())
}
/// Reads a message from the packet.
pub(crate) unsafe fn read(&self, token: &mut Token) -> Result<T, ()> {
// If there is no packet, the channel is disconnected.
if token.zero.0.is_null() {
return Err(());
}
let packet = unsafe { &*(token.zero.0 as *const Packet<T>) };
if packet.on_stack {
// The message has been in the packet from the beginning, so there is no need to wait
// for it. However, after reading the message, we need to set `ready` to `true` in
// order to signal that the packet can be destroyed.
let msg = unsafe { packet.msg.get().replace(None) }.unwrap();
packet.ready.store(true, Ordering::Release);
Ok(msg)
} else {
// Wait until the message becomes available, then read it and destroy the
// heap-allocated packet.
packet.wait_ready();
unsafe {
let msg = packet.msg.get().replace(None).unwrap();
drop(Box::from_raw(token.zero.0 as *mut Packet<T>));
Ok(msg)
}
}
}
/// Attempts to send a message into the channel.
pub(crate) fn try_send(&self, msg: T) -> Result<(), TrySendError<T>> {
let token = &mut Token::default();
let mut inner = self.inner.lock().unwrap();
// If there's a waiting receiver, pair up with it.
if let Some(operation) = inner.receivers.try_select() {
token.zero.0 = operation.packet;
drop(inner);
unsafe {
self.write(token, msg).ok().unwrap();
}
Ok(())
} else if inner.is_disconnected {
Err(TrySendError::Disconnected(msg))
} else {
Err(TrySendError::Full(msg))
}
}
/// Sends a message into the channel.
pub(crate) fn send(
&self,
msg: T,
deadline: Option<Instant>,
) -> Result<(), SendTimeoutError<T>> {
let token = &mut Token::default();
let mut inner = self.inner.lock().unwrap();
// If there's a waiting receiver, pair up with it.
if let Some(operation) = inner.receivers.try_select() {
token.zero.0 = operation.packet;
drop(inner);
unsafe {
self.write(token, msg).ok().unwrap();
}
return Ok(());
}
if inner.is_disconnected {
return Err(SendTimeoutError::Disconnected(msg));
}
Context::with(|cx| {
// Prepare for blocking until a receiver wakes us up.
let oper = Operation::hook(token);
let mut packet = Packet::<T>::message_on_stack(msg);
inner.senders.register_with_packet(oper, (&raw mut packet) as *mut (), cx);
inner.receivers.notify();
drop(inner);
// Block the current thread.
// SAFETY: the context belongs to the current thread.
let sel = unsafe { cx.wait_until(deadline) };
match sel {
Selected::Waiting => unreachable!(),
Selected::Aborted => {
self.inner.lock().unwrap().senders.unregister(oper).unwrap();
let msg = unsafe { packet.msg.get().replace(None).unwrap() };
Err(SendTimeoutError::Timeout(msg))
}
Selected::Disconnected => {
self.inner.lock().unwrap().senders.unregister(oper).unwrap();
let msg = unsafe { packet.msg.get().replace(None).unwrap() };
Err(SendTimeoutError::Disconnected(msg))
}
Selected::Operation(_) => {
// Wait until the message is read, then drop the packet.
packet.wait_ready();
Ok(())
}
}
})
}
/// Attempts to receive a message without blocking.
pub(crate) fn try_recv(&self) -> Result<T, TryRecvError> {
let token = &mut Token::default();
let mut inner = self.inner.lock().unwrap();
// If there's a waiting sender, pair up with it.
if let Some(operation) = inner.senders.try_select() {
token.zero.0 = operation.packet;
drop(inner);
unsafe { self.read(token).map_err(|_| TryRecvError::Disconnected) }
} else if inner.is_disconnected {
Err(TryRecvError::Disconnected)
} else {
Err(TryRecvError::Empty)
}
}
/// Receives a message from the channel.
pub(crate) fn recv(&self, deadline: Option<Instant>) -> Result<T, RecvTimeoutError> {
let token = &mut Token::default();
let mut inner = self.inner.lock().unwrap();
// If there's a waiting sender, pair up with it.
if let Some(operation) = inner.senders.try_select() {
token.zero.0 = operation.packet;
drop(inner);
unsafe {
return self.read(token).map_err(|_| RecvTimeoutError::Disconnected);
}
}
if inner.is_disconnected {
return Err(RecvTimeoutError::Disconnected);
}
Context::with(|cx| {
// Prepare for blocking until a sender wakes us up.
let oper = Operation::hook(token);
let mut packet = Packet::<T>::empty_on_stack();
inner.receivers.register_with_packet(oper, (&raw mut packet) as *mut (), cx);
inner.senders.notify();
drop(inner);
// Block the current thread.
// SAFETY: the context belongs to the current thread.
let sel = unsafe { cx.wait_until(deadline) };
match sel {
Selected::Waiting => unreachable!(),
Selected::Aborted => {
self.inner.lock().unwrap().receivers.unregister(oper).unwrap();
Err(RecvTimeoutError::Timeout)
}
Selected::Disconnected => {
self.inner.lock().unwrap().receivers.unregister(oper).unwrap();
Err(RecvTimeoutError::Disconnected)
}
Selected::Operation(_) => {
// Wait until the message is provided, then read it.
packet.wait_ready();
unsafe { Ok(packet.msg.get().replace(None).unwrap()) }
}
}
})
}
/// Disconnects the channel and wakes up all blocked senders and receivers.
///
/// Returns `true` if this call disconnected the channel.
pub(crate) fn disconnect(&self) -> bool {
let mut inner = self.inner.lock().unwrap();
if !inner.is_disconnected {
inner.is_disconnected = true;
inner.senders.disconnect();
inner.receivers.disconnect();
true
} else {
false
}
}
/// Returns the current number of messages inside the channel.
pub(crate) fn len(&self) -> usize {
0
}
/// Returns the capacity of the channel.
#[allow(clippy::unnecessary_wraps)] // This is intentional.
pub(crate) fn capacity(&self) -> Option<usize> {
Some(0)
}
/// Returns `true` if the channel is empty.
pub(crate) fn is_empty(&self) -> bool {
true
}
/// Returns `true` if the channel is full.
pub(crate) fn is_full(&self) -> bool {
true
}
}

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//! Non-poisoning synchronous locks.
//!
//! The difference from the locks in the [`poison`] module is that the locks in this module will not
//! become poisoned when a thread panics while holding a guard.
//!
//! [`poison`]: super::poison
use crate::fmt;
/// A type alias for the result of a nonblocking locking method.
#[unstable(feature = "sync_nonpoison", issue = "134645")]
pub type TryLockResult<Guard> = Result<Guard, WouldBlock>;
/// A lock could not be acquired at this time because the operation would otherwise block.
#[unstable(feature = "sync_nonpoison", issue = "134645")]
pub struct WouldBlock;
#[unstable(feature = "sync_nonpoison", issue = "134645")]
impl fmt::Debug for WouldBlock {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
"WouldBlock".fmt(f)
}
}
#[unstable(feature = "sync_nonpoison", issue = "134645")]
impl fmt::Display for WouldBlock {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
"try_lock failed because the operation would block".fmt(f)
}
}
#[unstable(feature = "nonpoison_condvar", issue = "134645")]
pub use self::condvar::Condvar;
#[unstable(feature = "mapped_lock_guards", issue = "117108")]
pub use self::mutex::MappedMutexGuard;
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
pub use self::mutex::{Mutex, MutexGuard};
#[unstable(feature = "mapped_lock_guards", issue = "117108")]
pub use self::rwlock::{MappedRwLockReadGuard, MappedRwLockWriteGuard};
#[unstable(feature = "nonpoison_rwlock", issue = "134645")]
pub use self::rwlock::{RwLock, RwLockReadGuard, RwLockWriteGuard};
mod condvar;
mod mutex;
mod rwlock;

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crates/std/src/sync/nonpoison/condvar.rs Normal file
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use crate::fmt;
use crate::ops::DerefMut;
use crate::sync::WaitTimeoutResult;
use crate::sync::nonpoison::{MutexGuard, mutex};
use crate::sys::sync as sys;
use crate::time::{Duration, Instant};
/// A Condition Variable
///
/// For more information about condition variables, check out the documentation for the poisoning
/// variant of this type at [`poison::Condvar`].
///
/// # Examples
///
/// Note that this `Condvar` does **not** propagate information about threads that panic while
/// holding a lock. If you need this functionality, see [`poison::Mutex`] and [`poison::Condvar`].
///
/// ```
/// #![feature(nonpoison_mutex)]
/// #![feature(nonpoison_condvar)]
///
/// use std::sync::nonpoison::{Mutex, Condvar};
/// use std::sync::Arc;
/// use std::thread;
///
/// let pair = Arc::new((Mutex::new(false), Condvar::new()));
/// let pair2 = Arc::clone(&pair);
///
/// // Inside of our lock, spawn a new thread, and then wait for it to start.
/// thread::spawn(move || {
/// let (lock, cvar) = &*pair2;
/// let mut started = lock.lock();
/// *started = true;
/// // We notify the condvar that the value has changed.
/// cvar.notify_one();
/// });
///
/// // Wait for the thread to start up.
/// let (lock, cvar) = &*pair;
/// let mut started = lock.lock();
/// while !*started {
/// cvar.wait(&mut started);
/// }
/// ```
///
/// [`poison::Mutex`]: crate::sync::poison::Mutex
/// [`poison::Condvar`]: crate::sync::poison::Condvar
#[unstable(feature = "nonpoison_condvar", issue = "134645")]
pub struct Condvar {
inner: sys::Condvar,
}
impl Condvar {
/// Creates a new condition variable which is ready to be waited on and
/// notified.
///
/// # Examples
///
/// ```
/// use std::sync::Condvar;
///
/// let condvar = Condvar::new();
/// ```
#[unstable(feature = "nonpoison_condvar", issue = "134645")]
#[must_use]
#[inline]
pub const fn new() -> Condvar {
Condvar { inner: sys::Condvar::new() }
}
/// Blocks the current thread until this condition variable receives a
/// notification.
///
/// This function will atomically unlock the mutex specified (represented by
/// `guard`) and block the current thread. This means that any calls
/// to [`notify_one`] or [`notify_all`] which happen logically after the
/// mutex is unlocked are candidates to wake this thread up. When this
/// function call returns, the lock specified will have been re-acquired.
///
/// Note that this function is susceptible to spurious wakeups. Condition
/// variables normally have a boolean predicate associated with them, and
/// the predicate must always be checked each time this function returns to
/// protect against spurious wakeups.
///
/// # Panics
///
/// This function may [`panic!`] if it is used with more than one mutex
/// over time.
///
/// [`notify_one`]: Self::notify_one
/// [`notify_all`]: Self::notify_all
///
/// # Examples
///
/// ```
/// #![feature(nonpoison_mutex)]
/// #![feature(nonpoison_condvar)]
///
/// use std::sync::nonpoison::{Mutex, Condvar};
/// use std::sync::Arc;
/// use std::thread;
///
/// let pair = Arc::new((Mutex::new(false), Condvar::new()));
/// let pair2 = Arc::clone(&pair);
///
/// thread::spawn(move || {
/// let (lock, cvar) = &*pair2;
/// let mut started = lock.lock();
/// *started = true;
/// // We notify the condvar that the value has changed.
/// cvar.notify_one();
/// });
///
/// // Wait for the thread to start up.
/// let (lock, cvar) = &*pair;
/// let mut started = lock.lock();
/// // As long as the value inside the `Mutex<bool>` is `false`, we wait.
/// while !*started {
/// cvar.wait(&mut started);
/// }
/// ```
#[unstable(feature = "nonpoison_condvar", issue = "134645")]
pub fn wait<T>(&self, guard: &mut MutexGuard<'_, T>) {
unsafe {
let lock = mutex::guard_lock(guard);
self.inner.wait(lock);
}
}
/// Blocks the current thread until the provided condition becomes false.
///
/// `condition` is checked immediately; if not met (returns `true`), this
/// will [`wait`] for the next notification then check again. This repeats
/// until `condition` returns `false`, in which case this function returns.
///
/// This function will atomically unlock the mutex specified (represented by
/// `guard`) and block the current thread. This means that any calls
/// to [`notify_one`] or [`notify_all`] which happen logically after the
/// mutex is unlocked are candidates to wake this thread up. When this
/// function call returns, the lock specified will have been re-acquired.
///
/// [`wait`]: Self::wait
/// [`notify_one`]: Self::notify_one
/// [`notify_all`]: Self::notify_all
///
/// # Examples
///
/// ```
/// #![feature(nonpoison_mutex)]
/// #![feature(nonpoison_condvar)]
///
/// use std::sync::nonpoison::{Mutex, Condvar};
/// use std::sync::Arc;
/// use std::thread;
///
/// let pair = Arc::new((Mutex::new(true), Condvar::new()));
/// let pair2 = Arc::clone(&pair);
///
/// thread::spawn(move || {
/// let (lock, cvar) = &*pair2;
/// let mut pending = lock.lock();
/// *pending = false;
/// // We notify the condvar that the value has changed.
/// cvar.notify_one();
/// });
///
/// // Wait for the thread to start up.
/// let (lock, cvar) = &*pair;
/// // As long as the value inside the `Mutex<bool>` is `true`, we wait.
/// let mut guard = lock.lock();
/// cvar.wait_while(&mut guard, |pending| { *pending });
/// ```
#[unstable(feature = "nonpoison_condvar", issue = "134645")]
pub fn wait_while<T, F>(&self, guard: &mut MutexGuard<'_, T>, mut condition: F)
where
F: FnMut(&mut T) -> bool,
{
while condition(guard.deref_mut()) {
self.wait(guard);
}
}
/// Waits on this condition variable for a notification, timing out after a
/// specified duration.
///
/// The semantics of this function are equivalent to [`wait`] except that
/// the thread will be blocked for roughly no longer than `dur`. This
/// method should not be used for precise timing due to anomalies such as
/// preemption or platform differences that might not cause the maximum
/// amount of time waited to be precisely `dur`.
///
/// Note that the best effort is made to ensure that the time waited is
/// measured with a monotonic clock, and not affected by the changes made to
/// the system time. This function is susceptible to spurious wakeups.
/// Condition variables normally have a boolean predicate associated with
/// them, and the predicate must always be checked each time this function
/// returns to protect against spurious wakeups. Furthermore, since the timeout
/// is given relative to the moment this function is called, it needs to be adjusted
/// when this function is called in a loop. The [`wait_timeout_while`] method
/// lets you wait with a timeout while a predicate is true, taking care of all these concerns.
///
/// The returned [`WaitTimeoutResult`] value indicates if the timeout is
/// known to have elapsed.
///
/// Like [`wait`], the lock specified will have been re-acquired when this function
/// returns, regardless of whether the timeout elapsed or not.
///
/// [`wait`]: Self::wait
/// [`wait_timeout_while`]: Self::wait_timeout_while
///
/// # Examples
///
/// ```
/// #![feature(nonpoison_mutex)]
/// #![feature(nonpoison_condvar)]
///
/// use std::sync::nonpoison::{Mutex, Condvar};
/// use std::sync::Arc;
/// use std::thread;
/// use std::time::Duration;
///
/// let pair = Arc::new((Mutex::new(false), Condvar::new()));
/// let pair2 = Arc::clone(&pair);
///
/// thread::spawn(move || {
/// let (lock, cvar) = &*pair2;
/// let mut started = lock.lock();
/// *started = true;
/// // We notify the condvar that the value has changed.
/// cvar.notify_one();
/// });
///
/// // wait for the thread to start up
/// let (lock, cvar) = &*pair;
/// let mut started = lock.lock();
/// // as long as the value inside the `Mutex<bool>` is `false`, we wait
/// loop {
/// let result = cvar.wait_timeout(&mut started, Duration::from_millis(10));
/// // 10 milliseconds have passed, or maybe the value changed!
/// if *started == true {
/// // We received the notification and the value has been updated, we can leave.
/// break
/// }
/// }
/// ```
#[unstable(feature = "nonpoison_condvar", issue = "134645")]
pub fn wait_timeout<T>(
&self,
guard: &mut MutexGuard<'_, T>,
dur: Duration,
) -> WaitTimeoutResult {
let success = unsafe {
let lock = mutex::guard_lock(guard);
self.inner.wait_timeout(lock, dur)
};
WaitTimeoutResult(!success)
}
/// Waits on this condition variable for a notification, timing out after a
/// specified duration.
///
/// The semantics of this function are equivalent to [`wait_while`] except
/// that the thread will be blocked for roughly no longer than `dur`. This
/// method should not be used for precise timing due to anomalies such as
/// preemption or platform differences that might not cause the maximum
/// amount of time waited to be precisely `dur`.
///
/// Note that the best effort is made to ensure that the time waited is
/// measured with a monotonic clock, and not affected by the changes made to
/// the system time.
///
/// The returned [`WaitTimeoutResult`] value indicates if the timeout is
/// known to have elapsed without the condition being met.
///
/// Like [`wait_while`], the lock specified will have been re-acquired when this
/// function returns, regardless of whether the timeout elapsed or not.
///
/// [`wait_while`]: Self::wait_while
/// [`wait_timeout`]: Self::wait_timeout
///
/// # Examples
///
/// ```
/// #![feature(nonpoison_mutex)]
/// #![feature(nonpoison_condvar)]
///
/// use std::sync::nonpoison::{Mutex, Condvar};
/// use std::sync::Arc;
/// use std::thread;
/// use std::time::Duration;
///
/// let pair = Arc::new((Mutex::new(true), Condvar::new()));
/// let pair2 = Arc::clone(&pair);
///
/// thread::spawn(move || {
/// let (lock, cvar) = &*pair2;
/// let mut pending = lock.lock();
/// *pending = false;
/// // We notify the condvar that the value has changed.
/// cvar.notify_one();
/// });
///
/// // wait for the thread to start up
/// let (lock, cvar) = &*pair;
/// let mut guard = lock.lock();
/// let result = cvar.wait_timeout_while(
/// &mut guard,
/// Duration::from_millis(100),
/// |&mut pending| pending,
/// );
/// if result.timed_out() {
/// // timed-out without the condition ever evaluating to false.
/// }
/// // access the locked mutex via guard
/// ```
#[unstable(feature = "nonpoison_condvar", issue = "134645")]
pub fn wait_timeout_while<T, F>(
&self,
guard: &mut MutexGuard<'_, T>,
dur: Duration,
mut condition: F,
) -> WaitTimeoutResult
where
F: FnMut(&mut T) -> bool,
{
let start = Instant::now();
while condition(guard.deref_mut()) {
let timeout = match dur.checked_sub(start.elapsed()) {
Some(timeout) => timeout,
None => return WaitTimeoutResult(true),
};
self.wait_timeout(guard, timeout);
}
WaitTimeoutResult(false)
}
/// Wakes up one blocked thread on this condvar.
///
/// If there is a blocked thread on this condition variable, then it will
/// be woken up from its call to [`wait`] or [`wait_timeout`]. Calls to
/// `notify_one` are not buffered in any way.
///
/// To wake up all threads, see [`notify_all`].
///
/// [`wait`]: Self::wait
/// [`wait_timeout`]: Self::wait_timeout
/// [`notify_all`]: Self::notify_all
///
/// # Examples
///
/// ```
/// #![feature(nonpoison_mutex)]
/// #![feature(nonpoison_condvar)]
///
/// use std::sync::nonpoison::{Mutex, Condvar};
/// use std::sync::Arc;
/// use std::thread;
///
/// let pair = Arc::new((Mutex::new(false), Condvar::new()));
/// let pair2 = Arc::clone(&pair);
///
/// thread::spawn(move || {
/// let (lock, cvar) = &*pair2;
/// let mut started = lock.lock();
/// *started = true;
/// // We notify the condvar that the value has changed.
/// cvar.notify_one();
/// });
///
/// // Wait for the thread to start up.
/// let (lock, cvar) = &*pair;
/// let mut started = lock.lock();
/// // As long as the value inside the `Mutex<bool>` is `false`, we wait.
/// while !*started {
/// cvar.wait(&mut started);
/// }
/// ```
#[unstable(feature = "nonpoison_condvar", issue = "134645")]
pub fn notify_one(&self) {
self.inner.notify_one()
}
/// Wakes up all blocked threads on this condvar.
///
/// This method will ensure that any current waiters on the condition
/// variable are awoken. Calls to `notify_all()` are not buffered in any
/// way.
///
/// To wake up only one thread, see [`notify_one`].
///
/// [`notify_one`]: Self::notify_one
///
/// # Examples
///
/// ```
/// #![feature(nonpoison_mutex)]
/// #![feature(nonpoison_condvar)]
///
/// use std::sync::nonpoison::{Mutex, Condvar};
/// use std::sync::Arc;
/// use std::thread;
///
/// let pair = Arc::new((Mutex::new(false), Condvar::new()));
/// let pair2 = Arc::clone(&pair);
///
/// thread::spawn(move || {
/// let (lock, cvar) = &*pair2;
/// let mut started = lock.lock();
/// *started = true;
/// // We notify the condvar that the value has changed.
/// cvar.notify_all();
/// });
///
/// // Wait for the thread to start up.
/// let (lock, cvar) = &*pair;
/// let mut started = lock.lock();
/// // As long as the value inside the `Mutex<bool>` is `false`, we wait.
/// while !*started {
/// cvar.wait(&mut started);
/// }
/// ```
#[unstable(feature = "nonpoison_condvar", issue = "134645")]
pub fn notify_all(&self) {
self.inner.notify_all()
}
}
#[unstable(feature = "nonpoison_condvar", issue = "134645")]
impl fmt::Debug for Condvar {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("Condvar").finish_non_exhaustive()
}
}
#[unstable(feature = "nonpoison_condvar", issue = "134645")]
impl Default for Condvar {
/// Creates a `Condvar` which is ready to be waited on and notified.
fn default() -> Condvar {
Condvar::new()
}
}

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use crate::cell::UnsafeCell;
use crate::fmt;
use crate::marker::PhantomData;
use crate::mem::{self, ManuallyDrop};
use crate::ops::{Deref, DerefMut};
use crate::ptr::NonNull;
use crate::sync::nonpoison::{TryLockResult, WouldBlock};
use crate::sys::sync as sys;
/// A mutual exclusion primitive useful for protecting shared data that does not keep track of
/// lock poisoning.
///
/// For more information about mutexes, check out the documentation for the poisoning variant of
/// this lock at [`poison::Mutex`].
///
/// [`poison::Mutex`]: crate::sync::poison::Mutex
///
/// # Examples
///
/// Note that this `Mutex` does **not** propagate threads that panic while holding the lock via
/// poisoning. If you need this functionality, see [`poison::Mutex`].
///
/// ```
/// #![feature(nonpoison_mutex)]
///
/// use std::thread;
/// use std::sync::{Arc, nonpoison::Mutex};
///
/// let mutex = Arc::new(Mutex::new(0u32));
/// let mut handles = Vec::new();
///
/// for n in 0..10 {
/// let m = Arc::clone(&mutex);
/// let handle = thread::spawn(move || {
/// let mut guard = m.lock();
/// *guard += 1;
/// panic!("panic from thread {n} {guard}")
/// });
/// handles.push(handle);
/// }
///
/// for h in handles {
/// let _ = h.join();
/// }
///
/// println!("Finished, locked {} times", mutex.lock());
/// ```
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
#[cfg_attr(not(test), rustc_diagnostic_item = "NonPoisonMutex")]
pub struct Mutex<T: ?Sized> {
inner: sys::Mutex,
data: UnsafeCell<T>,
}
/// `T` must be `Send` for a [`Mutex`] to be `Send` because it is possible to acquire
/// the owned `T` from the `Mutex` via [`into_inner`].
///
/// [`into_inner`]: Mutex::into_inner
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
unsafe impl<T: ?Sized + Send> Send for Mutex<T> {}
/// `T` must be `Send` for [`Mutex`] to be `Sync`.
/// This ensures that the protected data can be accessed safely from multiple threads
/// without causing data races or other unsafe behavior.
///
/// [`Mutex<T>`] provides mutable access to `T` to one thread at a time. However, it's essential
/// for `T` to be `Send` because it's not safe for non-`Send` structures to be accessed in
/// this manner. For instance, consider [`Rc`], a non-atomic reference counted smart pointer,
/// which is not `Send`. With `Rc`, we can have multiple copies pointing to the same heap
/// allocation with a non-atomic reference count. If we were to use `Mutex<Rc<_>>`, it would
/// only protect one instance of `Rc` from shared access, leaving other copies vulnerable
/// to potential data races.
///
/// Also note that it is not necessary for `T` to be `Sync` as `&T` is only made available
/// to one thread at a time if `T` is not `Sync`.
///
/// [`Rc`]: crate::rc::Rc
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
unsafe impl<T: ?Sized + Send> Sync for Mutex<T> {}
/// An RAII implementation of a "scoped lock" of a mutex. When this structure is
/// dropped (falls out of scope), the lock will be unlocked.
///
/// The data protected by the mutex can be accessed through this guard via its
/// [`Deref`] and [`DerefMut`] implementations.
///
/// This structure is created by the [`lock`] and [`try_lock`] methods on
/// [`Mutex`].
///
/// [`lock`]: Mutex::lock
/// [`try_lock`]: Mutex::try_lock
#[must_use = "if unused the Mutex will immediately unlock"]
#[must_not_suspend = "holding a MutexGuard across suspend \
points can cause deadlocks, delays, \
and cause Futures to not implement `Send`"]
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
#[clippy::has_significant_drop]
#[cfg_attr(not(test), rustc_diagnostic_item = "NonPoisonMutexGuard")]
pub struct MutexGuard<'a, T: ?Sized + 'a> {
lock: &'a Mutex<T>,
}
/// A [`MutexGuard`] is not `Send` to maximize platform portability.
///
/// On platforms that use POSIX threads (commonly referred to as pthreads) there is a requirement to
/// release mutex locks on the same thread they were acquired.
/// For this reason, [`MutexGuard`] must not implement `Send` to prevent it being dropped from
/// another thread.
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
impl<T: ?Sized> !Send for MutexGuard<'_, T> {}
/// `T` must be `Sync` for a [`MutexGuard<T>`] to be `Sync`
/// because it is possible to get a `&T` from `&MutexGuard` (via `Deref`).
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
unsafe impl<T: ?Sized + Sync> Sync for MutexGuard<'_, T> {}
/// An RAII mutex guard returned by `MutexGuard::map`, which can point to a
/// subfield of the protected data. When this structure is dropped (falls out
/// of scope), the lock will be unlocked.
///
/// The main difference between `MappedMutexGuard` and [`MutexGuard`] is that the
/// former cannot be used with [`Condvar`], since that could introduce soundness issues if the
/// locked object is modified by another thread while the `Mutex` is unlocked.
///
/// The data protected by the mutex can be accessed through this guard via its
/// [`Deref`] and [`DerefMut`] implementations.
///
/// This structure is created by the [`map`] and [`filter_map`] methods on
/// [`MutexGuard`].
///
/// [`map`]: MutexGuard::map
/// [`filter_map`]: MutexGuard::filter_map
/// [`Condvar`]: crate::sync::nonpoison::Condvar
#[must_use = "if unused the Mutex will immediately unlock"]
#[must_not_suspend = "holding a MappedMutexGuard across suspend \
points can cause deadlocks, delays, \
and cause Futures to not implement `Send`"]
#[unstable(feature = "mapped_lock_guards", issue = "117108")]
// #[unstable(feature = "nonpoison_mutex", issue = "134645")]
#[clippy::has_significant_drop]
pub struct MappedMutexGuard<'a, T: ?Sized + 'a> {
// NB: we use a pointer instead of `&'a mut T` to avoid `noalias` violations, because a
// `MappedMutexGuard` argument doesn't hold uniqueness for its whole scope, only until it drops.
// `NonNull` is covariant over `T`, so we add a `PhantomData<&'a mut T>` field
// below for the correct variance over `T` (invariance).
data: NonNull<T>,
inner: &'a sys::Mutex,
_variance: PhantomData<&'a mut T>,
}
#[unstable(feature = "mapped_lock_guards", issue = "117108")]
// #[unstable(feature = "nonpoison_mutex", issue = "134645")]
impl<T: ?Sized> !Send for MappedMutexGuard<'_, T> {}
#[unstable(feature = "mapped_lock_guards", issue = "117108")]
// #[unstable(feature = "nonpoison_mutex", issue = "134645")]
unsafe impl<T: ?Sized + Sync> Sync for MappedMutexGuard<'_, T> {}
impl<T> Mutex<T> {
/// Creates a new mutex in an unlocked state ready for use.
///
/// # Examples
///
/// ```
/// #![feature(nonpoison_mutex)]
///
/// use std::sync::nonpoison::Mutex;
///
/// let mutex = Mutex::new(0);
/// ```
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
#[inline]
pub const fn new(t: T) -> Mutex<T> {
Mutex { inner: sys::Mutex::new(), data: UnsafeCell::new(t) }
}
/// Returns the contained value by cloning it.
///
/// # Examples
///
/// ```
/// #![feature(nonpoison_mutex)]
/// #![feature(lock_value_accessors)]
///
/// use std::sync::nonpoison::Mutex;
///
/// let mut mutex = Mutex::new(7);
///
/// assert_eq!(mutex.get_cloned(), 7);
/// ```
#[unstable(feature = "lock_value_accessors", issue = "133407")]
// #[unstable(feature = "nonpoison_mutex", issue = "134645")]
pub fn get_cloned(&self) -> T
where
T: Clone,
{
self.lock().clone()
}
/// Sets the contained value.
///
/// # Examples
///
/// ```
/// #![feature(nonpoison_mutex)]
/// #![feature(lock_value_accessors)]
///
/// use std::sync::nonpoison::Mutex;
///
/// let mut mutex = Mutex::new(7);
///
/// assert_eq!(mutex.get_cloned(), 7);
/// mutex.set(11);
/// assert_eq!(mutex.get_cloned(), 11);
/// ```
#[unstable(feature = "lock_value_accessors", issue = "133407")]
// #[unstable(feature = "nonpoison_mutex", issue = "134645")]
pub fn set(&self, value: T) {
if mem::needs_drop::<T>() {
// If the contained value has a non-trivial destructor, we
// call that destructor after the lock has been released.
drop(self.replace(value))
} else {
*self.lock() = value;
}
}
/// Replaces the contained value with `value`, and returns the old contained value.
///
/// # Examples
///
/// ```
/// #![feature(nonpoison_mutex)]
/// #![feature(lock_value_accessors)]
///
/// use std::sync::nonpoison::Mutex;
///
/// let mut mutex = Mutex::new(7);
///
/// assert_eq!(mutex.replace(11), 7);
/// assert_eq!(mutex.get_cloned(), 11);
/// ```
#[unstable(feature = "lock_value_accessors", issue = "133407")]
// #[unstable(feature = "nonpoison_mutex", issue = "134645")]
pub fn replace(&self, value: T) -> T {
let mut guard = self.lock();
mem::replace(&mut *guard, value)
}
}
impl<T: ?Sized> Mutex<T> {
/// Acquires a mutex, blocking the current thread until it is able to do so.
///
/// This function will block the local thread until it is available to acquire
/// the mutex. Upon returning, the thread is the only thread with the lock
/// held. An RAII guard is returned to allow scoped unlock of the lock. When
/// the guard goes out of scope, the mutex will be unlocked.
///
/// The exact behavior on locking a mutex in the thread which already holds
/// the lock is left unspecified. However, this function will not return on
/// the second call (it might panic or deadlock, for example).
///
/// # Panics
///
/// This function might panic when called if the lock is already held by
/// the current thread.
///
/// # Examples
///
/// ```
/// #![feature(nonpoison_mutex)]
///
/// use std::sync::{Arc, nonpoison::Mutex};
/// use std::thread;
///
/// let mutex = Arc::new(Mutex::new(0));
/// let c_mutex = Arc::clone(&mutex);
///
/// thread::spawn(move || {
/// *c_mutex.lock() = 10;
/// }).join().expect("thread::spawn failed");
/// assert_eq!(*mutex.lock(), 10);
/// ```
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
pub fn lock(&self) -> MutexGuard<'_, T> {
unsafe {
self.inner.lock();
MutexGuard::new(self)
}
}
/// Attempts to acquire this lock.
///
/// This function does not block. If the lock could not be acquired at this time, then
/// [`WouldBlock`] is returned. Otherwise, an RAII guard is returned.
///
/// The lock will be unlocked when the guard is dropped.
///
/// # Errors
///
/// If the mutex could not be acquired because it is already locked, then this call will return
/// the [`WouldBlock`] error.
///
/// # Examples
///
/// ```
/// use std::sync::{Arc, Mutex};
/// use std::thread;
///
/// let mutex = Arc::new(Mutex::new(0));
/// let c_mutex = Arc::clone(&mutex);
///
/// thread::spawn(move || {
/// let mut lock = c_mutex.try_lock();
/// if let Ok(ref mut mutex) = lock {
/// **mutex = 10;
/// } else {
/// println!("try_lock failed");
/// }
/// }).join().expect("thread::spawn failed");
/// assert_eq!(*mutex.lock().unwrap(), 10);
/// ```
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
pub fn try_lock(&self) -> TryLockResult<MutexGuard<'_, T>> {
unsafe { if self.inner.try_lock() { Ok(MutexGuard::new(self)) } else { Err(WouldBlock) } }
}
/// Consumes this mutex, returning the underlying data.
///
/// # Examples
///
/// ```
/// #![feature(nonpoison_mutex)]
///
/// use std::sync::nonpoison::Mutex;
///
/// let mutex = Mutex::new(0);
/// assert_eq!(mutex.into_inner(), 0);
/// ```
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
pub fn into_inner(self) -> T
where
T: Sized,
{
self.data.into_inner()
}
/// Returns a mutable reference to the underlying data.
///
/// Since this call borrows the `Mutex` mutably, no actual locking needs to
/// take place -- the mutable borrow statically guarantees no locks exist.
///
/// # Examples
///
/// ```
/// #![feature(nonpoison_mutex)]
///
/// use std::sync::nonpoison::Mutex;
///
/// let mut mutex = Mutex::new(0);
/// *mutex.get_mut() = 10;
/// assert_eq!(*mutex.lock(), 10);
/// ```
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
pub fn get_mut(&mut self) -> &mut T {
self.data.get_mut()
}
/// Returns a raw pointer to the underlying data.
///
/// The returned pointer is always non-null and properly aligned, but it is
/// the user's responsibility to ensure that any reads and writes through it
/// are properly synchronized to avoid data races, and that it is not read
/// or written through after the mutex is dropped.
#[unstable(feature = "mutex_data_ptr", issue = "140368")]
// #[unstable(feature = "nonpoison_mutex", issue = "134645")]
pub const fn data_ptr(&self) -> *mut T {
self.data.get()
}
/// Acquires the mutex and provides mutable access to the underlying data by passing
/// a mutable reference to the given closure.
///
/// This method acquires the lock, calls the provided closure with a mutable reference
/// to the data, and returns the result of the closure. The lock is released after
/// the closure completes, even if it panics.
///
/// # Examples
///
/// ```
/// #![feature(lock_value_accessors, nonpoison_mutex)]
///
/// use std::sync::nonpoison::Mutex;
///
/// let mutex = Mutex::new(2);
///
/// let result = mutex.with_mut(|data| {
/// *data += 3;
///
/// *data + 5
/// });
///
/// assert_eq!(*mutex.lock(), 5);
/// assert_eq!(result, 10);
/// ```
#[unstable(feature = "lock_value_accessors", issue = "133407")]
// #[unstable(feature = "nonpoison_mutex", issue = "134645")]
pub fn with_mut<F, R>(&self, f: F) -> R
where
F: FnOnce(&mut T) -> R,
{
f(&mut self.lock())
}
}
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
impl<T> From<T> for Mutex<T> {
/// Creates a new mutex in an unlocked state ready for use.
/// This is equivalent to [`Mutex::new`].
fn from(t: T) -> Self {
Mutex::new(t)
}
}
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
impl<T: Default> Default for Mutex<T> {
/// Creates a `Mutex<T>`, with the `Default` value for T.
fn default() -> Mutex<T> {
Mutex::new(Default::default())
}
}
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
impl<T: ?Sized + fmt::Debug> fmt::Debug for Mutex<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut d = f.debug_struct("Mutex");
match self.try_lock() {
Ok(guard) => {
d.field("data", &&*guard);
}
Err(WouldBlock) => {
d.field("data", &"<locked>");
}
}
d.finish_non_exhaustive()
}
}
impl<'mutex, T: ?Sized> MutexGuard<'mutex, T> {
unsafe fn new(lock: &'mutex Mutex<T>) -> MutexGuard<'mutex, T> {
return MutexGuard { lock };
}
}
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
impl<T: ?Sized> Deref for MutexGuard<'_, T> {
type Target = T;
fn deref(&self) -> &T {
unsafe { &*self.lock.data.get() }
}
}
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
impl<T: ?Sized> DerefMut for MutexGuard<'_, T> {
fn deref_mut(&mut self) -> &mut T {
unsafe { &mut *self.lock.data.get() }
}
}
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
impl<T: ?Sized> Drop for MutexGuard<'_, T> {
#[inline]
fn drop(&mut self) {
unsafe {
self.lock.inner.unlock();
}
}
}
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
impl<T: ?Sized + fmt::Debug> fmt::Debug for MutexGuard<'_, T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Debug::fmt(&**self, f)
}
}
#[unstable(feature = "nonpoison_mutex", issue = "134645")]
impl<T: ?Sized + fmt::Display> fmt::Display for MutexGuard<'_, T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
(**self).fmt(f)
}
}
/// For use in [`nonpoison::condvar`](super::condvar).
pub(super) fn guard_lock<'a, T: ?Sized>(guard: &MutexGuard<'a, T>) -> &'a sys::Mutex {
&guard.lock.inner
}
impl<'a, T: ?Sized> MutexGuard<'a, T> {
/// Makes a [`MappedMutexGuard`] for a component of the borrowed data, e.g.
/// an enum variant.
///
/// The `Mutex` is already locked, so this cannot fail.
///
/// This is an associated function that needs to be used as
/// `MutexGuard::map(...)`. A method would interfere with methods of the
/// same name on the contents of the `MutexGuard` used through `Deref`.
#[unstable(feature = "mapped_lock_guards", issue = "117108")]
// #[unstable(feature = "nonpoison_mutex", issue = "134645")]
pub fn map<U, F>(orig: Self, f: F) -> MappedMutexGuard<'a, U>
where
F: FnOnce(&mut T) -> &mut U,
U: ?Sized,
{
// SAFETY: the conditions of `MutexGuard::new` were satisfied when the original guard
// was created, and have been upheld throughout `map` and/or `filter_map`.
// The signature of the closure guarantees that it will not "leak" the lifetime of the reference
// passed to it. If the closure panics, the guard will be dropped.
let data = NonNull::from(f(unsafe { &mut *orig.lock.data.get() }));
let orig = ManuallyDrop::new(orig);
MappedMutexGuard { data, inner: &orig.lock.inner, _variance: PhantomData }
}
/// Makes a [`MappedMutexGuard`] for a component of the borrowed data. The
/// original guard is returned as an `Err(...)` if the closure returns
/// `None`.
///
/// The `Mutex` is already locked, so this cannot fail.
///
/// This is an associated function that needs to be used as
/// `MutexGuard::filter_map(...)`. A method would interfere with methods of the
/// same name on the contents of the `MutexGuard` used through `Deref`.
#[unstable(feature = "mapped_lock_guards", issue = "117108")]
// #[unstable(feature = "nonpoison_mutex", issue = "134645")]
pub fn filter_map<U, F>(orig: Self, f: F) -> Result<MappedMutexGuard<'a, U>, Self>
where
F: FnOnce(&mut T) -> Option<&mut U>,
U: ?Sized,
{
// SAFETY: the conditions of `MutexGuard::new` were satisfied when the original guard
// was created, and have been upheld throughout `map` and/or `filter_map`.
// The signature of the closure guarantees that it will not "leak" the lifetime of the reference
// passed to it. If the closure panics, the guard will be dropped.
match f(unsafe { &mut *orig.lock.data.get() }) {
Some(data) => {
let data = NonNull::from(data);
let orig = ManuallyDrop::new(orig);
Ok(MappedMutexGuard { data, inner: &orig.lock.inner, _variance: PhantomData })
}
None => Err(orig),
}
}
}
#[unstable(feature = "mapped_lock_guards", issue = "117108")]
impl<T: ?Sized> Deref for MappedMutexGuard<'_, T> {
type Target = T;
fn deref(&self) -> &T {
unsafe { self.data.as_ref() }
}
}
#[unstable(feature = "mapped_lock_guards", issue = "117108")]
impl<T: ?Sized> DerefMut for MappedMutexGuard<'_, T> {
fn deref_mut(&mut self) -> &mut T {
unsafe { self.data.as_mut() }
}
}
#[unstable(feature = "mapped_lock_guards", issue = "117108")]
impl<T: ?Sized> Drop for MappedMutexGuard<'_, T> {
#[inline]
fn drop(&mut self) {
unsafe {
self.inner.unlock();
}
}
}
#[unstable(feature = "mapped_lock_guards", issue = "117108")]
impl<T: ?Sized + fmt::Debug> fmt::Debug for MappedMutexGuard<'_, T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Debug::fmt(&**self, f)
}
}
#[unstable(feature = "mapped_lock_guards", issue = "117108")]
impl<T: ?Sized + fmt::Display> fmt::Display for MappedMutexGuard<'_, T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
(**self).fmt(f)
}
}
impl<'a, T: ?Sized> MappedMutexGuard<'a, T> {
/// Makes a [`MappedMutexGuard`] for a component of the borrowed data, e.g.
/// an enum variant.
///
/// The `Mutex` is already locked, so this cannot fail.
///
/// This is an associated function that needs to be used as
/// `MappedMutexGuard::map(...)`. A method would interfere with methods of the
/// same name on the contents of the `MutexGuard` used through `Deref`.
#[unstable(feature = "mapped_lock_guards", issue = "117108")]
// #[unstable(feature = "nonpoison_mutex", issue = "134645")]
pub fn map<U, F>(mut orig: Self, f: F) -> MappedMutexGuard<'a, U>
where
F: FnOnce(&mut T) -> &mut U,
U: ?Sized,
{
// SAFETY: the conditions of `MutexGuard::new` were satisfied when the original guard
// was created, and have been upheld throughout `map` and/or `filter_map`.
// The signature of the closure guarantees that it will not "leak" the lifetime of the reference
// passed to it. If the closure panics, the guard will be dropped.
let data = NonNull::from(f(unsafe { orig.data.as_mut() }));
let orig = ManuallyDrop::new(orig);
MappedMutexGuard { data, inner: orig.inner, _variance: PhantomData }
}
/// Makes a [`MappedMutexGuard`] for a component of the borrowed data. The
/// original guard is returned as an `Err(...)` if the closure returns
/// `None`.
///
/// The `Mutex` is already locked, so this cannot fail.
///
/// This is an associated function that needs to be used as
/// `MappedMutexGuard::filter_map(...)`. A method would interfere with methods of the
/// same name on the contents of the `MutexGuard` used through `Deref`.
#[unstable(feature = "mapped_lock_guards", issue = "117108")]
// #[unstable(feature = "nonpoison_mutex", issue = "134645")]
pub fn filter_map<U, F>(mut orig: Self, f: F) -> Result<MappedMutexGuard<'a, U>, Self>
where
F: FnOnce(&mut T) -> Option<&mut U>,
U: ?Sized,
{
// SAFETY: the conditions of `MutexGuard::new` were satisfied when the original guard
// was created, and have been upheld throughout `map` and/or `filter_map`.
// The signature of the closure guarantees that it will not "leak" the lifetime of the reference
// passed to it. If the closure panics, the guard will be dropped.
match f(unsafe { orig.data.as_mut() }) {
Some(data) => {
let data = NonNull::from(data);
let orig = ManuallyDrop::new(orig);
Ok(MappedMutexGuard { data, inner: orig.inner, _variance: PhantomData })
}
None => Err(orig),
}
}
}

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