1 files changed, 84 insertions, 0 deletions
diff --git a/third_party/rust/futures-0.1.31/src/stream/inspect.rs b/third_party/rust/futures-0.1.31/src/stream/inspect.rs
new file mode 100644
index 0000000000..fc8f7f4ea2
--- /dev/null
+++ b/third_party/rust/futures-0.1.31/src/stream/inspect.rs
@@ -0,0 +1,84 @@
+use {Stream, Poll, Async};
+
+/// Do something with the items of a stream, passing it on.
+///
+/// This is created by the `Stream::inspect` method.
+#[derive(Debug)]
+#[must_use = "streams do nothing unless polled"]
+pub struct Inspect<S, F> where S: Stream {
+    stream: S,
+    inspect: F,
+}
+
+pub fn new<S, F>(stream: S, f: F) -> Inspect<S, F>
+    where S: Stream,
+          F: FnMut(&S::Item) -> (),
+{
+    Inspect {
+        stream: stream,
+        inspect: f,
+    }
+}
+
+impl<S: Stream, F> Inspect<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 Inspect<S, F>
+    where S: ::sink::Sink + Stream
+{
+    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> Stream for Inspect<S, F>
+    where S: Stream,
+          F: FnMut(&S::Item),
+{
+    type Item = S::Item;
+    type Error = S::Error;
+
+    fn poll(&mut self) -> Poll<Option<S::Item>, S::Error> {
+        match try_ready!(self.stream.poll()) {
+            Some(e) => {
+                (self.inspect)(&e);
+                Ok(Async::Ready(Some(e)))
+            }
+            None => Ok(Async::Ready(None)),
+        }
+    }
+}