1use crate::stream::TryStreamExt;
2use core::pin::Pin;
3use futures_core::future::{FusedFuture, Future};
4use futures_core::stream::{FusedStream, TryStream};
5use 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"]
10pub struct TryNext<'a, St: ?Sized> {
11 stream: &'a mut St,
12}
13
14impl<St: ?Sized + Unpin> Unpin for TryNext<'_, St> {}
15
16impl<'a, St: ?Sized + TryStream + Unpin> TryNext<'a, St> {
17 pub(super) fn new(stream: &'a mut St) -> Self {
18 Self { stream }
19 }
20}
21
22impl<St: ?Sized + TryStream + Unpin + FusedStream> FusedFuture for TryNext<'_, St> {
23 fn is_terminated(&self) -> bool {
24 self.stream.is_terminated()
25 }
26}
27
28impl<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