From 26a029d407be480d791972afb5975cf62c9360a6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 19 Apr 2024 02:47:55 +0200 Subject: Adding upstream version 124.0.1. Signed-off-by: Daniel Baumann --- third_party/rust/futures-util/src/stream/repeat.rs | 58 ++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 third_party/rust/futures-util/src/stream/repeat.rs (limited to 'third_party/rust/futures-util/src/stream/repeat.rs') diff --git a/third_party/rust/futures-util/src/stream/repeat.rs b/third_party/rust/futures-util/src/stream/repeat.rs new file mode 100644 index 0000000000..3f9aa87d5c --- /dev/null +++ b/third_party/rust/futures-util/src/stream/repeat.rs @@ -0,0 +1,58 @@ +use super::assert_stream; +use core::pin::Pin; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; + +/// Stream for the [`repeat`] function. +#[derive(Debug, Clone)] +#[must_use = "streams do nothing unless polled"] +pub struct Repeat { + item: T, +} + +/// Create a stream which produces the same item repeatedly. +/// +/// The stream never terminates. Note that you likely want to avoid +/// usage of `collect` or such on the returned stream as it will exhaust +/// available memory as it tries to just fill up all RAM. +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::stream::{self, StreamExt}; +/// +/// let stream = stream::repeat(9); +/// assert_eq!(vec![9, 9, 9], stream.take(3).collect::>().await); +/// # }); +/// ``` +pub fn repeat(item: T) -> Repeat +where + T: Clone, +{ + assert_stream::(Repeat { item }) +} + +impl Unpin for Repeat {} + +impl Stream for Repeat +where + T: Clone, +{ + type Item = T; + + fn poll_next(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll> { + Poll::Ready(Some(self.item.clone())) + } + + fn size_hint(&self) -> (usize, Option) { + (usize::max_value(), None) + } +} + +impl FusedStream for Repeat +where + T: Clone, +{ + fn is_terminated(&self) -> bool { + false + } +} -- cgit v1.2.3