| use crate::stream::StreamExt; |
| use core::pin::Pin; |
| use futures_core::future::{FusedFuture, Future}; |
| use futures_core::stream::{FusedStream, Stream}; |
| use futures_core::task::{Context, Poll}; |
| |
| /// Future for the [`next`](super::StreamExt::next) method. |
| #[derive(Debug)] |
| #[must_use = "futures do nothing unless you `.await` or poll them"] |
| pub struct Next<'a, St: ?Sized> { |
| stream: &'a mut St, |
| } |
| |
| impl<St: ?Sized + Unpin> Unpin for Next<'_, St> {} |
| |
| impl<'a, St: ?Sized + Stream + Unpin> Next<'a, St> { |
| pub(super) fn new(stream: &'a mut St) -> Self { |
| Next { stream } |
| } |
| } |
| |
| impl<St: ?Sized + FusedStream + Unpin> FusedFuture for Next<'_, St> { |
| fn is_terminated(&self) -> bool { |
| self.stream.is_terminated() |
| } |
| } |
| |
| impl<St: ?Sized + Stream + Unpin> Future for Next<'_, St> { |
| type Output = Option<St::Item>; |
| |
| fn poll( |
| mut self: Pin<&mut Self>, |
| cx: &mut Context<'_>, |
| ) -> Poll<Self::Output> { |
| self.stream.poll_next_unpin(cx) |
| } |
| } |