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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
commit36d22d82aa202bb199967e9512281e9a53db42c9 (patch)
tree105e8c98ddea1c1e4784a60a5a6410fa416be2de /third_party/rust/tokio-stream/src/pending.rs
parentInitial commit. (diff)
downloadfirefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz
firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip
Adding upstream version 115.7.0esr.upstream/115.7.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/tokio-stream/src/pending.rs')
-rw-r--r--third_party/rust/tokio-stream/src/pending.rs54
1 files changed, 54 insertions, 0 deletions
diff --git a/third_party/rust/tokio-stream/src/pending.rs b/third_party/rust/tokio-stream/src/pending.rs
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+use crate::Stream;
+
+use core::marker::PhantomData;
+use core::pin::Pin;
+use core::task::{Context, Poll};
+
+/// Stream for the [`pending`](fn@pending) function.
+#[derive(Debug)]
+#[must_use = "streams do nothing unless polled"]
+pub struct Pending<T>(PhantomData<T>);
+
+impl<T> Unpin for Pending<T> {}
+unsafe impl<T> Send for Pending<T> {}
+unsafe impl<T> Sync for Pending<T> {}
+
+/// Creates a stream that is never ready
+///
+/// The returned stream is never ready. Attempting to call
+/// [`next()`](crate::StreamExt::next) will never complete. Use
+/// [`stream::empty()`](super::empty()) to obtain a stream that is is
+/// immediately empty but returns no values.
+///
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```no_run
+/// use tokio_stream::{self as stream, StreamExt};
+///
+/// #[tokio::main]
+/// async fn main() {
+/// let mut never = stream::pending::<i32>();
+///
+/// // This will never complete
+/// never.next().await;
+///
+/// unreachable!();
+/// }
+/// ```
+pub const fn pending<T>() -> Pending<T> {
+ Pending(PhantomData)
+}
+
+impl<T> Stream for Pending<T> {
+ type Item = T;
+
+ fn poll_next(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Option<T>> {
+ Poll::Pending
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ (0, None)
+ }
+}