| use core::pin::Pin; |
| use futures_core::future::Future; |
| use futures_core::ready; |
| use futures_core::task::{Context, Poll}; |
| use futures_sink::Sink; |
| |
| /// Future for the [`feed`](super::SinkExt::feed) method. |
| #[derive(Debug)] |
| #[must_use = "futures do nothing unless you `.await` or poll them"] |
| pub struct Feed<'a, Si: ?Sized, Item> { |
| sink: &'a mut Si, |
| item: Option<Item>, |
| } |
| |
| // Pinning is never projected to children |
| impl<Si: Unpin + ?Sized, Item> Unpin for Feed<'_, Si, Item> {} |
| |
| impl<'a, Si: Sink<Item> + Unpin + ?Sized, Item> Feed<'a, Si, Item> { |
| pub(super) fn new(sink: &'a mut Si, item: Item) -> Self { |
| Feed { sink, item: Some(item) } |
| } |
| |
| pub(super) fn sink_pin_mut(&mut self) -> Pin<&mut Si> { |
| Pin::new(self.sink) |
| } |
| |
| pub(super) fn is_item_pending(&self) -> bool { |
| self.item.is_some() |
| } |
| } |
| |
| impl<Si: Sink<Item> + Unpin + ?Sized, Item> Future for Feed<'_, Si, Item> { |
| type Output = Result<(), Si::Error>; |
| |
| fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { |
| let this = self.get_mut(); |
| let mut sink = Pin::new(&mut this.sink); |
| ready!(sink.as_mut().poll_ready(cx))?; |
| let item = this.item.take().expect("polled Feed after completion"); |
| sink.as_mut().start_send(item)?; |
| Poll::Ready(Ok(())) |
| } |
| } |