1 files changed, 89 insertions, 0 deletions
diff --git a/third_party/rust/futures-0.1.31/src/stream/fuse.rs b/third_party/rust/futures-0.1.31/src/stream/fuse.rs
new file mode 100644
index 0000000000..e39c31f348
--- /dev/null
+++ b/third_party/rust/futures-0.1.31/src/stream/fuse.rs
@@ -0,0 +1,89 @@
+use {Poll, Async};
+use stream::Stream;
+
+/// A stream which "fuse"s a stream once it's terminated.
+///
+/// Normally streams can behave unpredictably when used after they have already
+/// finished, but `Fuse` continues to return `None` from `poll` forever when
+/// finished.
+#[derive(Debug)]
+#[must_use = "streams do nothing unless polled"]
+pub struct Fuse<S> {
+    stream: S,
+    done: bool,
+}
+
+// Forwarding impl of Sink from the underlying stream
+impl<S> ::sink::Sink for Fuse<S>
+    where S: ::sink::Sink
+{
+    type SinkItem = S::SinkItem;
+    type SinkError = S::SinkError;
+
+    fn start_send(&mut self, item: S::SinkItem) -> ::StartSend<S::SinkItem, S::SinkError> {
+        self.stream.start_send(item)
+    }
+
+    fn poll_complete(&mut self) -> Poll<(), S::SinkError> {
+        self.stream.poll_complete()
+    }
+
+    fn close(&mut self) -> Poll<(), S::SinkError> {
+        self.stream.close()
+    }
+}
+
+pub fn new<S: Stream>(s: S) -> Fuse<S> {
+    Fuse { stream: s, done: false }
+}
+
+impl<S: Stream> Stream for Fuse<S> {
+    type Item = S::Item;
+    type Error = S::Error;
+
+    fn poll(&mut self) -> Poll<Option<S::Item>, S::Error> {
+        if self.done {
+            Ok(Async::Ready(None))
+        } else {
+            let r = self.stream.poll();
+            if let Ok(Async::Ready(None)) = r {
+                self.done = true;
+            }
+            r
+        }
+    }
+}
+
+impl<S> Fuse<S> {
+    /// Returns whether the underlying stream has finished or not.
+    ///
+    /// If this method returns `true`, then all future calls to poll are
+    /// guaranteed to return `None`. If this returns `false`, then the
+    /// underlying stream is still in use.
+    pub fn is_done(&self) -> bool {
+        self.done
+    }
+
+    /// Acquires a reference to the underlying stream that this combinator is
+    /// pulling from.
+    pub fn get_ref(&self) -> &S {
+        &self.stream
+    }
+
+    /// Acquires a mutable reference to the underlying stream that this
+    /// combinator is pulling from.
+    ///
+    /// Note that care must be taken to avoid tampering with the state of the
+    /// stream which may otherwise confuse this combinator.
+    pub fn get_mut(&mut self) -> &mut S {
+        &mut self.stream
+    }
+
+    /// Consumes this combinator, returning the underlying stream.
+    ///
+    /// Note that this may discard intermediate state of this combinator, so
+    /// care should be taken to avoid losing resources when this is called.
+    pub fn into_inner(self) -> S {
+        self.stream
+    }
+}