Files
tokio/tokio-io/src/io/buf_stream.rs
T

110 lines
3.5 KiB
Rust

use crate::io::{BufReader, BufWriter};
use crate::{AsyncBufRead, AsyncRead, AsyncWrite};
use pin_project::pin_project;
use std::io::{self};
use std::{
pin::Pin,
task::{Context, Poll},
};
/// Wraps a type that is [`AsyncWrite`] and [`AsyncRead`], and buffers its input and output.
///
/// It can be excessively inefficient to work directly with something that implements [`AsyncWrite`]
/// and [`AsyncRead`]. For example, every `write`, however small, has to traverse the syscall
/// interface, and similarly, every read has to do the same. The [`BufWriter`] and [`BufReader`]
/// types aid with these problems respectively, but do so in only one direction. `BufStream` wraps
/// one in the other so that both directions are buffered. See their documentation for details.
#[pin_project]
#[derive(Debug)]
pub struct BufStream<RW>(#[pin] BufReader<BufWriter<RW>>);
impl<RW: AsyncRead + AsyncWrite> BufStream<RW> {
/// Wrap a type in both [`BufWriter`] and [`BufReader`].
///
/// See the documentation for those types and [`BufStream`] for details.
pub fn new(stream: RW) -> BufStream<RW> {
BufStream(BufReader::new(BufWriter::new(stream)))
}
/// Gets a reference to the underlying I/O object.
///
/// It is inadvisable to directly read from the underlying I/O object.
pub fn get_ref(&self) -> &RW {
self.0.get_ref().get_ref()
}
/// Gets a mutable reference to the underlying I/O object.
///
/// It is inadvisable to directly read from the underlying I/O object.
pub fn get_mut(&mut self) -> &mut RW {
self.0.get_mut().get_mut()
}
/// Gets a pinned mutable reference to the underlying I/O object.
///
/// It is inadvisable to directly read from the underlying I/O object.
pub fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut RW> {
self.project().0.get_pin_mut().get_pin_mut()
}
/// Consumes this `BufStream`, returning the underlying I/O object.
///
/// Note that any leftover data in the internal buffer is lost.
pub fn into_inner(self) -> RW {
self.0.into_inner().into_inner()
}
}
impl<RW: AsyncRead + AsyncWrite> AsyncWrite for BufStream<RW> {
fn poll_write(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<io::Result<usize>> {
self.project().0.poll_write(cx, buf)
}
fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
self.project().0.poll_flush(cx)
}
fn poll_shutdown(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
self.project().0.poll_shutdown(cx)
}
}
impl<RW: AsyncRead + AsyncWrite> AsyncRead for BufStream<RW> {
fn poll_read(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8],
) -> Poll<io::Result<usize>> {
self.project().0.poll_read(cx, buf)
}
// we can't skip unconditionally because of the large buffer case in read.
unsafe fn prepare_uninitialized_buffer(&self, buf: &mut [u8]) -> bool {
self.0.prepare_uninitialized_buffer(buf)
}
}
impl<RW: AsyncBufRead + AsyncRead + AsyncWrite> AsyncBufRead for BufStream<RW> {
fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<&[u8]>> {
self.project().0.poll_fill_buf(cx)
}
fn consume(self: Pin<&mut Self>, amt: usize) {
self.project().0.consume(amt)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn assert_unpin() {
crate::is_unpin::<BufStream<()>>();
}
}