diff options
Diffstat (limited to 'src/stream/fold.rs')
-rw-r--r-- | src/stream/fold.rs | 57 |
1 files changed, 0 insertions, 57 deletions
diff --git a/src/stream/fold.rs b/src/stream/fold.rs deleted file mode 100644 index 5cf2bfa..0000000 --- a/src/stream/fold.rs +++ /dev/null @@ -1,57 +0,0 @@ -use crate::stream::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 returned by the [`fold`](super::StreamExt::fold) method. - #[derive(Debug)] - #[must_use = "futures do nothing unless you `.await` or poll them"] - pub struct FoldFuture<St, B, F> { - #[pin] - stream: St, - acc: Option<B>, - f: F, - // Make this future `!Unpin` for compatibility with async trait methods. - #[pin] - _pin: PhantomPinned, - } -} - -impl<St, B, F> FoldFuture<St, B, F> { - pub(super) fn new(stream: St, init: B, f: F) -> Self { - Self { - stream, - acc: Some(init), - f, - _pin: PhantomPinned, - } - } -} - -impl<St, B, F> Future for FoldFuture<St, B, F> -where - St: Stream, - F: FnMut(B, St::Item) -> B, -{ - type Output = B; - - fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { - let mut me = self.project(); - loop { - let next = ready!(me.stream.as_mut().poll_next(cx)); - - match next { - Some(v) => { - let old = me.acc.take().unwrap(); - let new = (me.f)(old, v); - *me.acc = Some(new); - } - None => return Poll::Ready(me.acc.take().unwrap()), - } - } - } -} |