| use core::pin::Pin; |
| use futures_core::stream::FusedStream; |
| use futures_core::future::{Future, FusedFuture}; |
| use futures_core::task::{Context, Poll}; |
| use crate::stream::StreamExt; |
| |
| /// Future for the [`select_next_some`](super::StreamExt::select_next_some) |
| /// method. |
| #[derive(Debug)] |
| #[must_use = "futures do nothing unless you `.await` or poll them"] |
| pub struct SelectNextSome<'a, St: ?Sized> { |
| stream: &'a mut St, |
| } |
| |
| impl<'a, St: ?Sized> SelectNextSome<'a, St> { |
| pub(super) fn new(stream: &'a mut St) -> Self { |
| SelectNextSome { stream } |
| } |
| } |
| |
| impl<St: ?Sized + FusedStream + Unpin> FusedFuture for SelectNextSome<'_, St> { |
| fn is_terminated(&self) -> bool { |
| self.stream.is_terminated() |
| } |
| } |
| |
| impl<St: ?Sized + FusedStream + Unpin> Future for SelectNextSome<'_, St> { |
| type Output = St::Item; |
| |
| fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { |
| assert!(!self.stream.is_terminated(), "SelectNextSome polled after terminated"); |
| |
| if let Some(item) = ready!(self.stream.poll_next_unpin(cx)) { |
| Poll::Ready(item) |
| } else { |
| debug_assert!(self.stream.is_terminated()); |
| cx.waker().wake_by_ref(); |
| Poll::Pending |
| } |
| } |
| } |