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-rw-r--r--src/stream_ext/try_next.rs39
1 files changed, 39 insertions, 0 deletions
diff --git a/src/stream_ext/try_next.rs b/src/stream_ext/try_next.rs
new file mode 100644
index 0000000..af27d87
--- /dev/null
+++ b/src/stream_ext/try_next.rs
@@ -0,0 +1,39 @@
+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)
+ }
+}