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