blob: 4f1e84b9b99da76155d5b0f75970a311e33d4deb [file] [log] [blame]
use crate::lock::BiLock;
use futures_core::task::{self, Poll};
use futures_io::{AsyncRead, AsyncWrite, IoVec};
use std::io;
use std::pin::PinMut;
/// The readable half of an object returned from `AsyncRead::split`.
#[derive(Debug)]
pub struct ReadHalf<T> {
handle: BiLock<T>,
}
/// The writable half of an object returned from `AsyncRead::split`.
#[derive(Debug)]
pub struct WriteHalf<T> {
handle: BiLock<T>,
}
fn lock_and_then<T, U, E, F>(
lock: &BiLock<T>,
cx: &mut task::Context,
f: F
) -> Poll<Result<U, E>>
where F: FnOnce(&mut T, &mut task::Context) -> Poll<Result<U, E>>
{
match lock.poll_lock(cx) {
// Safety: the value behind the bilock used by `ReadHalf` and `WriteHalf` is never exposed
// as a `PinMut` anywhere other than here as a way to get to `&mut`.
Poll::Ready(mut l) => f(unsafe { PinMut::get_mut_unchecked(l.as_pin_mut()) }, cx),
Poll::Pending => Poll::Pending,
}
}
pub fn split<T: AsyncRead + AsyncWrite>(t: T) -> (ReadHalf<T>, WriteHalf<T>) {
let (a, b) = BiLock::new(t);
(ReadHalf { handle: a }, WriteHalf { handle: b })
}
impl<R: AsyncRead> AsyncRead for ReadHalf<R> {
fn poll_read(&mut self, cx: &mut task::Context, buf: &mut [u8])
-> Poll<io::Result<usize>>
{
lock_and_then(&self.handle, cx, |l, cx| l.poll_read(cx, buf))
}
fn poll_vectored_read(&mut self, cx: &mut task::Context, vec: &mut [&mut IoVec])
-> Poll<io::Result<usize>>
{
lock_and_then(&self.handle, cx, |l, cx| l.poll_vectored_read(cx, vec))
}
}
impl<W: AsyncWrite> AsyncWrite for WriteHalf<W> {
fn poll_write(&mut self, cx: &mut task::Context, buf: &[u8])
-> Poll<io::Result<usize>>
{
lock_and_then(&self.handle, cx, |l, cx| l.poll_write(cx, buf))
}
fn poll_vectored_write(&mut self, cx: &mut task::Context, vec: &[&IoVec])
-> Poll<io::Result<usize>>
{
lock_and_then(&self.handle, cx, |l, cx| l.poll_vectored_write(cx, vec))
}
fn poll_flush(&mut self, cx: &mut task::Context) -> Poll<io::Result<()>> {
lock_and_then(&self.handle, cx, |l, cx| l.poll_flush(cx))
}
fn poll_close(&mut self, cx: &mut task::Context) -> Poll<io::Result<()>> {
lock_and_then(&self.handle, cx, |l, cx| l.poll_close(cx))
}
}