| use core::pin::Pin; |
| use futures_core::future::Future; |
| use futures_core::stream::TryStream; |
| use futures_core::task::{Context, Poll}; |
| use pin_project::pin_project; |
| |
| /// Future for the [`try_concat`](super::TryStreamExt::try_concat) method. |
| #[pin_project] |
| #[derive(Debug)] |
| #[must_use = "futures do nothing unless you `.await` or poll them"] |
| pub struct TryConcat<St: TryStream> { |
| #[pin] |
| stream: St, |
| accum: Option<St::Ok>, |
| } |
| |
| impl<St> TryConcat<St> |
| where |
| St: TryStream, |
| St::Ok: Extend<<St::Ok as IntoIterator>::Item> + IntoIterator + Default, |
| { |
| pub(super) fn new(stream: St) -> TryConcat<St> { |
| TryConcat { |
| stream, |
| accum: None, |
| } |
| } |
| } |
| |
| impl<St> Future for TryConcat<St> |
| where |
| St: TryStream, |
| St::Ok: Extend<<St::Ok as IntoIterator>::Item> + IntoIterator + Default, |
| { |
| type Output = Result<St::Ok, St::Error>; |
| |
| fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { |
| let mut this = self.project(); |
| |
| Poll::Ready(Ok(loop { |
| if let Some(x) = ready!(this.stream.as_mut().try_poll_next(cx)?) { |
| if let Some(a) = this.accum { |
| a.extend(x) |
| } else { |
| *this.accum = Some(x) |
| } |
| } else { |
| break this.accum.take().unwrap_or_default(); |
| } |
| })) |
| } |
| } |