mirror of
https://github.com/tokio-rs/tokio.git
synced 2026-09-09 00:00:08 +02:00
Carl Lerche
b479ce78d3
This patch adds experimental async/await support to Tokio. It does this by adding feature flags to existing libs only where necessary in order to add nightly specific code (mostly `Unpin` implementations). It then provides a new crate: `tokio-async-await` which is a shim layer on top of `tokio`. The `tokio-async-await` crate is expected to look exactly like `tokio` does, but with async / await support. This strategy reduces the amount of cfg guarding in the main libraries. This patch also adds `tokio-channel`, which is copied from futures-rs 0.1 and adds the necessary `Unpin` implementations. In general, futures 0.1 is mostly unmaintained, so it will make sense for Tokio to take over maintainership of key components regardless of async / await support.
60 lines
1.6 KiB
Rust
60 lines
1.6 KiB
Rust
use futures::Sink;
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use futures_core::future::Future;
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use futures_core::task::{self, Poll};
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use std::marker::Unpin;
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use std::mem::PinMut;
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/// Future for the `SinkExt::send_async` combinator, which sends a value to a
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/// sink and then waits until the sink has fully flushed.
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#[derive(Debug)]
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pub struct Send<'a, T: Sink + 'a + ?Sized> {
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sink: &'a mut T,
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item: Option<T::SinkItem>,
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}
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impl<T: Sink + Unpin + ?Sized> Unpin for Send<'_, T> {}
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impl<'a, T: Sink + Unpin + ?Sized> Send<'a, T> {
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pub(super) fn new(sink: &'a mut T, item: T::SinkItem) -> Self {
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Send {
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sink,
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item: Some(item),
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}
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}
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}
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impl<T: Sink + Unpin + ?Sized> Future for Send<'_, T> {
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type Output = Result<(), T::SinkError>;
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fn poll(mut self: PinMut<Self>, _cx: &mut task::Context) -> Poll<Self::Output> {
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use crate::async_await::compat::forward::convert_poll;
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use futures::AsyncSink::{Ready, NotReady};
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use futures_util::try_ready;
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// use crate::compat::forward::convert_poll;
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let this = &mut *self;
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if let Some(item) = this.item.take() {
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match this.sink.start_send(item) {
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Ok(Ready) => {}
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Ok(NotReady(val)) => {
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self.item = Some(val);
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return Poll::Pending;
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}
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Err(err) => {
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return Poll::Ready(Err(err));
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}
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}
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}
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// we're done sending the item, but want to block on flushing the
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// sink
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try_ready!(convert_poll(this.sink.poll_complete()));
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Poll::Ready(Ok(()))
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}
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}
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