1 files changed, 80 insertions, 0 deletions
diff --git a/third_party/rust/futures-0.1.31/src/stream/map_err.rs b/third_party/rust/futures-0.1.31/src/stream/map_err.rs
new file mode 100644
index 0000000000..8d1c0fc083
--- /dev/null
+++ b/third_party/rust/futures-0.1.31/src/stream/map_err.rs
@@ -0,0 +1,80 @@
+use Poll;
+use stream::Stream;
+
+/// A stream combinator which will change the error type of a stream from one
+/// type to another.
+///
+/// This is produced by the `Stream::map_err` method.
+#[derive(Debug)]
+#[must_use = "streams do nothing unless polled"]
+pub struct MapErr<S, F> {
+    stream: S,
+    f: F,
+}
+
+pub fn new<S, F, U>(s: S, f: F) -> MapErr<S, F>
+    where S: Stream,
+          F: FnMut(S::Error) -> U,
+{
+    MapErr {
+        stream: s,
+        f: f,
+    }
+}
+
+impl<S, F> MapErr<S, F> {
+    /// 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
+    }
+}
+
+// Forwarding impl of Sink from the underlying stream
+impl<S, F> ::sink::Sink for MapErr<S, F>
+    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()
+    }
+}
+
+impl<S, F, U> Stream for MapErr<S, F>
+    where S: Stream,
+          F: FnMut(S::Error) -> U,
+{
+    type Item = S::Item;
+    type Error = U;
+
+    fn poll(&mut self) -> Poll<Option<S::Item>, U> {
+        self.stream.poll().map_err(&mut self.f)
+    }
+}