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use core::pin::Pin;
use futures_core::future::Future;
use futures_core::task::{Context, Poll};
use futures_sink::Sink;
#[derive(Debug)]
#[must_use = "futures do nothing unless you `.await` or poll them"]
pub struct Send<'a, Si: ?Sized, Item> {
sink: &'a mut Si,
item: Option<Item>,
}
impl<Si: Unpin + ?Sized, Item> Unpin for Send<'_, Si, Item> {}
impl<'a, Si: Sink<Item> + Unpin + ?Sized, Item> Send<'a, Si, Item> {
pub(super) fn new(sink: &'a mut Si, item: Item) -> Self {
Send {
sink,
item: Some(item),
}
}
}
impl<Si: Sink<Item> + Unpin + ?Sized, Item> Future for Send<'_, Si, Item> {
type Output = Result<(), Si::Error>;
fn poll(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Self::Output> {
let this = &mut *self;
if let Some(item) = this.item.take() {
let mut sink = Pin::new(&mut this.sink);
match sink.as_mut().poll_ready(cx)? {
Poll::Ready(()) => sink.as_mut().start_send(item)?,
Poll::Pending => {
this.item = Some(item);
return Poll::Pending;
}
}
}
ready!(Pin::new(&mut this.sink).poll_flush(cx))?;
Poll::Ready(Ok(()))
}
}