1 | use core::marker::PhantomData; |
2 | use core::pin::Pin; |
3 | use futures_core::future::Future; |
4 | use futures_core::task::{Context, Poll}; |
5 | use futures_sink::Sink; |
6 | |
7 | /// Future for the [`flush`](super::SinkExt::flush) method. |
8 | #[derive (Debug)] |
9 | #[must_use = "futures do nothing unless you `.await` or poll them" ] |
10 | pub struct Flush<'a, Si: ?Sized, Item> { |
11 | sink: &'a mut Si, |
12 | _phantom: PhantomData<fn(Item)>, |
13 | } |
14 | |
15 | // Pin is never projected to a field. |
16 | impl<Si: Unpin + ?Sized, Item> Unpin for Flush<'_, Si, Item> {} |
17 | |
18 | /// A future that completes when the sink has finished processing all |
19 | /// pending requests. |
20 | /// |
21 | /// The sink itself is returned after flushing is complete; this adapter is |
22 | /// intended to be used when you want to stop sending to the sink until |
23 | /// all current requests are processed. |
24 | impl<'a, Si: Sink<Item> + Unpin + ?Sized, Item> Flush<'a, Si, Item> { |
25 | pub(super) fn new(sink: &'a mut Si) -> Self { |
26 | Self { sink, _phantom: PhantomData } |
27 | } |
28 | } |
29 | |
30 | impl<Si: Sink<Item> + Unpin + ?Sized, Item> Future for Flush<'_, Si, Item> { |
31 | type Output = Result<(), Si::Error>; |
32 | |
33 | fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { |
34 | Pin::new(&mut self.sink).poll_flush(cx) |
35 | } |
36 | } |
37 | |