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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /vendor/futures-util/src/stream/try_stream/or_else.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | vendor/futures-util/src/stream/try_stream/or_else.rs | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/vendor/futures-util/src/stream/try_stream/or_else.rs b/vendor/futures-util/src/stream/try_stream/or_else.rs new file mode 100644 index 000000000..cb69e8132 --- /dev/null +++ b/vendor/futures-util/src/stream/try_stream/or_else.rs @@ -0,0 +1,109 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::TryFuture; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream, TryStream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`or_else`](super::TryStreamExt::or_else) method. + #[must_use = "streams do nothing unless polled"] + pub struct OrElse<St, Fut, F> { + #[pin] + stream: St, + #[pin] + future: Option<Fut>, + f: F, + } +} + +impl<St, Fut, F> fmt::Debug for OrElse<St, Fut, F> +where + St: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("OrElse") + .field("stream", &self.stream) + .field("future", &self.future) + .finish() + } +} + +impl<St, Fut, F> OrElse<St, Fut, F> +where + St: TryStream, + F: FnMut(St::Error) -> Fut, + Fut: TryFuture<Ok = St::Ok>, +{ + pub(super) fn new(stream: St, f: F) -> Self { + Self { stream, future: None, f } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St, Fut, F> Stream for OrElse<St, Fut, F> +where + St: TryStream, + F: FnMut(St::Error) -> Fut, + Fut: TryFuture<Ok = St::Ok>, +{ + type Item = Result<St::Ok, Fut::Error>; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + Poll::Ready(loop { + if let Some(fut) = this.future.as_mut().as_pin_mut() { + let item = ready!(fut.try_poll(cx)); + this.future.set(None); + break Some(item); + } else { + match ready!(this.stream.as_mut().try_poll_next(cx)) { + Some(Ok(item)) => break Some(Ok(item)), + Some(Err(e)) => { + this.future.set(Some((this.f)(e))); + } + None => break None, + } + } + }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let future_len = if self.future.is_some() { 1 } else { 0 }; + let (lower, upper) = self.stream.size_hint(); + let lower = lower.saturating_add(future_len); + let upper = match upper { + Some(x) => x.checked_add(future_len), + None => None, + }; + (lower, upper) + } +} + +impl<St, Fut, F> FusedStream for OrElse<St, Fut, F> +where + St: TryStream + FusedStream, + F: FnMut(St::Error) -> Fut, + Fut: TryFuture<Ok = St::Ok>, +{ + fn is_terminated(&self) -> bool { + self.future.is_none() && self.stream.is_terminated() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Fut, F, Item> Sink<Item> for OrElse<S, Fut, F> +where + S: Sink<Item>, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} |