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Rollup merge of #120053 - AldanTanneo:specialize-stdinlock-bytes, r=the8472

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Specialize `Bytes` on `StdinLock<'_>`

I noticed recently, while profiling a little project, that I was spending a lot of time reading from stdin (even with locking). I was using the `.bytes()` iterator adaptor; I figured, since `StdinLock` is a `BufReader` internally, it would work just as fast. But this is not the case, as `Bytes` is only specialized for the raw `BufReader`, and not the `StdinLock`/`MutexGuard` wrapper. Performance improved significantly when I wrapped the lock in a new `BufReader`, but I was still a bit sore about the double buffer indirection.

This PR attempts to specialize it, by simply calling the already specialized implementation on `BufReader`.
This commit is contained in:
Matthias Krüger 2024-01-26 06:36:37 +01:00 committed by GitHub
commit cfa583b388
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1 changed files with 10 additions and 1 deletions
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11
library/std/src/io/stdio.rs
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@ -8,7 +8,9 @@ use crate::io::prelude::*;
use crate::cell::{Cell, RefCell};
use crate::fmt;
use crate::fs::File;
use crate::io::{self, BorrowedCursor, BufReader, IoSlice, IoSliceMut, LineWriter, Lines};
use crate::io::{
self, BorrowedCursor, BufReader, IoSlice, IoSliceMut, LineWriter, Lines, SpecReadByte,
};
use crate::sync::atomic::{AtomicBool, Ordering};
use crate::sync::{Arc, Mutex, MutexGuard, OnceLock, ReentrantMutex, ReentrantMutexGuard};
use crate::sys::stdio;
@ -483,6 +485,13 @@ impl Read for StdinLock<'_> {
}
}
impl SpecReadByte for StdinLock<'_> {
#[inline]
fn spec_read_byte(&mut self) -> Option<io::Result<u8>> {
BufReader::spec_read_byte(&mut *self.inner)
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl BufRead for StdinLock<'_> {
fn fill_buf(&mut self) -> io::Result<&[u8]> {