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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
commit | 26a029d407be480d791972afb5975cf62c9360a6 (patch) | |
tree | f435a8308119effd964b339f76abb83a57c29483 /third_party/rust/futures-util/src/stream/repeat.rs | |
parent | Initial commit. (diff) | |
download | firefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz firefox-26a029d407be480d791972afb5975cf62c9360a6.zip |
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/futures-util/src/stream/repeat.rs')
-rw-r--r-- | third_party/rust/futures-util/src/stream/repeat.rs | 58 |
1 files changed, 58 insertions, 0 deletions
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<T> { + 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::<Vec<i32>>().await); +/// # }); +/// ``` +pub fn repeat<T>(item: T) -> Repeat<T> +where + T: Clone, +{ + assert_stream::<T, _>(Repeat { item }) +} + +impl<T> Unpin for Repeat<T> {} + +impl<T> Stream for Repeat<T> +where + T: Clone, +{ + type Item = T; + + fn poll_next(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Option<Self::Item>> { + Poll::Ready(Some(self.item.clone())) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + (usize::max_value(), None) + } +} + +impl<T> FusedStream for Repeat<T> +where + T: Clone, +{ + fn is_terminated(&self) -> bool { + false + } +} |