1 files changed, 54 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..21749eb71d
--- /dev/null
+++ b/third_party/rust/futures-util/src/stream/repeat.rs
@@ -0,0 +1,54 @@
+use core::pin::Pin;
+use futures_core::stream::{Stream, FusedStream};
+use futures_core::task::{Context, Poll};
+
+/// Stream for the [`repeat`] function.
+#[derive(Debug)]
+#[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
+{
+    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
+    }
+}