futures_util/sink/
send.rs

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1use super::Feed;
2use core::pin::Pin;
3use futures_core::future::Future;
4use futures_core::ready;
5use futures_core::task::{Context, Poll};
6use futures_sink::Sink;
7
8/// Future for the [`send`](super::SinkExt::send) method.
9#[derive(Debug)]
10#[must_use = "futures do nothing unless you `.await` or poll them"]
11pub struct Send<'a, Si: ?Sized, Item> {
12    feed: Feed<'a, Si, Item>,
13}
14
15// Pinning is never projected to children
16impl<Si: Unpin + ?Sized, Item> Unpin for Send<'_, Si, Item> {}
17
18impl<'a, Si: Sink<Item> + Unpin + ?Sized, Item> Send<'a, Si, Item> {
19    pub(super) fn new(sink: &'a mut Si, item: Item) -> Self {
20        Self { feed: Feed::new(sink, item) }
21    }
22}
23
24impl<Si: Sink<Item> + Unpin + ?Sized, Item> Future for Send<'_, Si, Item> {
25    type Output = Result<(), Si::Error>;
26
27    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
28        let this = &mut *self;
29
30        if this.feed.is_item_pending() {
31            ready!(Pin::new(&mut this.feed).poll(cx))?;
32            debug_assert!(!this.feed.is_item_pending());
33        }
34
35        // we're done sending the item, but want to block on flushing the
36        // sink
37        ready!(this.feed.sink_pin_mut().poll_flush(cx))?;
38
39        Poll::Ready(Ok(()))
40    }
41}
futures_util/sink/send.rs

futures_util/sink/
send.rs
