| use crate::stream_ext::Next; |
| use crate::Stream; |
| |
| use core::future::Future; |
| use core::marker::PhantomPinned; |
| use core::pin::Pin; |
| use core::task::{Context, Poll}; |
| use pin_project_lite::pin_project; |
| |
| pin_project! { |
| /// Future for the [`try_next`](super::StreamExt::try_next) method. |
| #[derive(Debug)] |
| #[must_use = "futures do nothing unless you `.await` or poll them"] |
| pub struct TryNext<'a, St: ?Sized> { |
| #[pin] |
| inner: Next<'a, St>, |
| // Make this future `!Unpin` for compatibility with async trait methods. |
| #[pin] |
| _pin: PhantomPinned, |
| } |
| } |
| |
| impl<'a, St: ?Sized> TryNext<'a, St> { |
| pub(super) fn new(stream: &'a mut St) -> Self { |
| Self { |
| inner: Next::new(stream), |
| _pin: PhantomPinned, |
| } |
| } |
| } |
| |
| impl<T, E, St: ?Sized + Stream<Item = Result<T, E>> + Unpin> Future for TryNext<'_, St> { |
| type Output = Result<Option<T>, E>; |
| |
| fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { |
| let me = self.project(); |
| me.inner.poll(cx).map(Option::transpose) |
| } |
| } |