1 | use crate::stream::TryStreamExt; |
2 | use core::pin::Pin; |
3 | use futures_core::future::{FusedFuture, Future}; |
4 | use futures_core::stream::{FusedStream, TryStream}; |
5 | use futures_core::task::{Context, Poll}; |
6 | |
7 | /// Future for the [`try_next`](super::TryStreamExt::try_next) method. |
8 | #[derive (Debug)] |
9 | #[must_use = "futures do nothing unless you `.await` or poll them" ] |
10 | pub struct TryNext<'a, St: ?Sized> { |
11 | stream: &'a mut St, |
12 | } |
13 | |
14 | impl<St: ?Sized + Unpin> Unpin for TryNext<'_, St> {} |
15 | |
16 | impl<'a, St: ?Sized + TryStream + Unpin> TryNext<'a, St> { |
17 | pub(super) fn new(stream: &'a mut St) -> Self { |
18 | Self { stream } |
19 | } |
20 | } |
21 | |
22 | impl<St: ?Sized + TryStream + Unpin + FusedStream> FusedFuture for TryNext<'_, St> { |
23 | fn is_terminated(&self) -> bool { |
24 | self.stream.is_terminated() |
25 | } |
26 | } |
27 | |
28 | impl<St: ?Sized + TryStream + Unpin> Future for TryNext<'_, St> { |
29 | type Output = Result<Option<St::Ok>, St::Error>; |
30 | |
31 | fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { |
32 | self.stream.try_poll_next_unpin(cx)?.map(Ok) |
33 | } |
34 | } |
35 | |