116 lines
3.7 KiB
Rust
116 lines
3.7 KiB
Rust
use crate::lock::BiLock;
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use core::fmt;
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use futures_core::ready;
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use futures_core::task::{Context, Poll};
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use futures_io::{AsyncRead, AsyncWrite, IoSlice, IoSliceMut};
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use std::io;
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use std::pin::Pin;
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/// The readable half of an object returned from `AsyncRead::split`.
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#[derive(Debug)]
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pub struct ReadHalf<T> {
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handle: BiLock<T>,
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}
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/// The writable half of an object returned from `AsyncRead::split`.
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#[derive(Debug)]
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pub struct WriteHalf<T> {
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handle: BiLock<T>,
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}
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fn lock_and_then<T, U, E, F>(lock: &BiLock<T>, cx: &mut Context<'_>, f: F) -> Poll<Result<U, E>>
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where
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F: FnOnce(Pin<&mut T>, &mut Context<'_>) -> Poll<Result<U, E>>,
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{
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let mut l = ready!(lock.poll_lock(cx));
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f(l.as_pin_mut(), cx)
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}
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pub(super) fn split<T: AsyncRead + AsyncWrite>(t: T) -> (ReadHalf<T>, WriteHalf<T>) {
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let (a, b) = BiLock::new(t);
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(ReadHalf { handle: a }, WriteHalf { handle: b })
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}
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impl<T: Unpin> ReadHalf<T> {
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/// Attempts to put the two "halves" of a split `AsyncRead + AsyncWrite` back
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/// together. Succeeds only if the `ReadHalf<T>` and `WriteHalf<T>` are
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/// a matching pair originating from the same call to `AsyncReadExt::split`.
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pub fn reunite(self, other: WriteHalf<T>) -> Result<T, ReuniteError<T>> {
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self.handle
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.reunite(other.handle)
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.map_err(|err| ReuniteError(ReadHalf { handle: err.0 }, WriteHalf { handle: err.1 }))
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}
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}
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impl<T: Unpin> WriteHalf<T> {
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/// Attempts to put the two "halves" of a split `AsyncRead + AsyncWrite` back
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/// together. Succeeds only if the `ReadHalf<T>` and `WriteHalf<T>` are
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/// a matching pair originating from the same call to `AsyncReadExt::split`.
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pub fn reunite(self, other: ReadHalf<T>) -> Result<T, ReuniteError<T>> {
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other.reunite(self)
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}
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}
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impl<R: AsyncRead> AsyncRead for ReadHalf<R> {
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fn poll_read(
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self: Pin<&mut Self>,
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cx: &mut Context<'_>,
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buf: &mut [u8],
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) -> Poll<io::Result<usize>> {
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lock_and_then(&self.handle, cx, |l, cx| l.poll_read(cx, buf))
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}
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fn poll_read_vectored(
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self: Pin<&mut Self>,
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cx: &mut Context<'_>,
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bufs: &mut [IoSliceMut<'_>],
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) -> Poll<io::Result<usize>> {
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lock_and_then(&self.handle, cx, |l, cx| l.poll_read_vectored(cx, bufs))
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}
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}
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impl<W: AsyncWrite> AsyncWrite for WriteHalf<W> {
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fn poll_write(
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self: Pin<&mut Self>,
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cx: &mut Context<'_>,
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buf: &[u8],
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) -> Poll<io::Result<usize>> {
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lock_and_then(&self.handle, cx, |l, cx| l.poll_write(cx, buf))
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}
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fn poll_write_vectored(
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self: Pin<&mut Self>,
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cx: &mut Context<'_>,
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bufs: &[IoSlice<'_>],
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) -> Poll<io::Result<usize>> {
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lock_and_then(&self.handle, cx, |l, cx| l.poll_write_vectored(cx, bufs))
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}
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fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
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lock_and_then(&self.handle, cx, |l, cx| l.poll_flush(cx))
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}
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fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
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lock_and_then(&self.handle, cx, |l, cx| l.poll_close(cx))
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}
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}
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/// Error indicating a `ReadHalf<T>` and `WriteHalf<T>` were not two halves
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/// of a `AsyncRead + AsyncWrite`, and thus could not be `reunite`d.
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pub struct ReuniteError<T>(pub ReadHalf<T>, pub WriteHalf<T>);
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impl<T> fmt::Debug for ReuniteError<T> {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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f.debug_tuple("ReuniteError").field(&"...").finish()
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}
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}
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impl<T> fmt::Display for ReuniteError<T> {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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write!(f, "tried to reunite a ReadHalf and WriteHalf that don't form a pair")
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}
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}
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#[cfg(feature = "std")]
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impl<T: core::any::Any> std::error::Error for ReuniteError<T> {}
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