1 files changed, 114 insertions, 0 deletions
diff --git a/third_party/rust/futures-0.1.29/src/stream/channel.rs b/third_party/rust/futures-0.1.29/src/stream/channel.rs
new file mode 100644
index 0000000000..89a419d150
--- /dev/null
+++ b/third_party/rust/futures-0.1.29/src/stream/channel.rs
@@ -0,0 +1,114 @@
+#![cfg(feature = "with-deprecated")]
+#![deprecated(since = "0.1.4", note = "use sync::mpsc::channel instead")]
+#![allow(deprecated)]
+
+use std::any::Any;
+use std::error::Error;
+use std::fmt;
+
+use {Poll, Async, Stream, Future, Sink};
+use sink::Send;
+use sync::mpsc;
+
+/// Creates an in-memory channel implementation of the `Stream` trait.
+///
+/// This method creates a concrete implementation of the `Stream` trait which
+/// can be used to send values across threads in a streaming fashion. This
+/// channel is unique in that it implements back pressure to ensure that the
+/// sender never outpaces the receiver. The `Sender::send` method will only
+/// allow sending one message and the next message can only be sent once the
+/// first was consumed.
+///
+/// The `Receiver` returned implements the `Stream` trait and has access to any
+/// number of the associated combinators for transforming the result.
+pub fn channel<T, E>() -> (Sender<T, E>, Receiver<T, E>) {
+    let (tx, rx) = mpsc::channel(0);
+    (Sender { inner: tx }, Receiver { inner: rx })
+}
+
+/// The transmission end of a channel which is used to send values.
+///
+/// This is created by the `channel` method in the `stream` module.
+#[derive(Debug)]
+pub struct Sender<T, E> {
+    inner: mpsc::Sender<Result<T, E>>,
+}
+
+/// The receiving end of a channel which implements the `Stream` trait.
+///
+/// This is a concrete implementation of a stream which can be used to represent
+/// a stream of values being computed elsewhere. This is created by the
+/// `channel` method in the `stream` module.
+#[must_use = "streams do nothing unless polled"]
+#[derive(Debug)]
+pub struct Receiver<T, E> {
+    inner: mpsc::Receiver<Result<T, E>>,
+}
+
+/// Error type for sending, used when the receiving end of the channel is dropped
+pub struct SendError<T, E>(Result<T, E>);
+
+/// Future returned by `Sender::send`.
+#[derive(Debug)]
+pub struct FutureSender<T, E> {
+    inner: Send<mpsc::Sender<Result<T, E>>>,
+}
+
+impl<T, E> fmt::Debug for SendError<T, E> {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_tuple("SendError")
+            .field(&"...")
+            .finish()
+    }
+}
+
+impl<T, E> fmt::Display for SendError<T, E> {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        write!(fmt, "send failed because receiver is gone")
+    }
+}
+
+impl<T, E> Error for SendError<T, E>
+    where T: Any, E: Any
+{
+    fn description(&self) -> &str {
+        "send failed because receiver is gone"
+    }
+}
+
+
+impl<T, E> Stream for Receiver<T, E> {
+    type Item = T;
+    type Error = E;
+
+    fn poll(&mut self) -> Poll<Option<T>, E> {
+        match self.inner.poll().expect("cannot fail") {
+            Async::Ready(Some(Ok(e))) => Ok(Async::Ready(Some(e))),
+            Async::Ready(Some(Err(e))) => Err(e),
+            Async::Ready(None) => Ok(Async::Ready(None)),
+            Async::NotReady => Ok(Async::NotReady),
+        }
+    }
+}
+
+impl<T, E> Sender<T, E> {
+    /// Sends a new value along this channel to the receiver.
+    ///
+    /// This method consumes the sender and returns a future which will resolve
+    /// to the sender again when the value sent has been consumed.
+    pub fn send(self, t: Result<T, E>) -> FutureSender<T, E> {
+        FutureSender { inner: self.inner.send(t) }
+    }
+}
+
+impl<T, E> Future for FutureSender<T, E> {
+    type Item = Sender<T, E>;
+    type Error = SendError<T, E>;
+
+    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
+        match self.inner.poll() {
+            Ok(a) => Ok(a.map(|a| Sender { inner: a })),
+            Err(e) => Err(SendError(e.into_inner())),
+        }
+    }
+}