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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/stream_ext/chain.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/stream_ext/chain.rs')
-rw-r--r--third_party/rust/tokio-stream/src/stream_ext/chain.rs50
1 files changed, 50 insertions, 0 deletions
diff --git a/third_party/rust/tokio-stream/src/stream_ext/chain.rs b/third_party/rust/tokio-stream/src/stream_ext/chain.rs
new file mode 100644
index 0000000000..bd64f33ce4
--- /dev/null
+++ b/third_party/rust/tokio-stream/src/stream_ext/chain.rs
@@ -0,0 +1,50 @@
+use crate::stream_ext::Fuse;
+use crate::Stream;
+
+use core::pin::Pin;
+use core::task::{Context, Poll};
+use pin_project_lite::pin_project;
+
+pin_project! {
+ /// Stream returned by the [`chain`](super::StreamExt::chain) method.
+ pub struct Chain<T, U> {
+ #[pin]
+ a: Fuse<T>,
+ #[pin]
+ b: U,
+ }
+}
+
+impl<T, U> Chain<T, U> {
+ pub(super) fn new(a: T, b: U) -> Chain<T, U>
+ where
+ T: Stream,
+ U: Stream,
+ {
+ Chain { a: Fuse::new(a), b }
+ }
+}
+
+impl<T, U> Stream for Chain<T, U>
+where
+ T: Stream,
+ U: Stream<Item = T::Item>,
+{
+ type Item = T::Item;
+
+ fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<T::Item>> {
+ use Poll::Ready;
+
+ let me = self.project();
+
+ if let Some(v) = ready!(me.a.poll_next(cx)) {
+ return Ready(Some(v));
+ }
+
+ me.b.poll_next(cx)
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ super::merge_size_hints(self.a.size_hint(), self.b.size_hint())
+ }
+}