1 files changed, 35 insertions, 0 deletions
diff --git a/third_party/rust/futures-0.1.29/src/future/from_err.rs b/third_party/rust/futures-0.1.29/src/future/from_err.rs
new file mode 100644
index 0000000000..97e35d7cc7
--- /dev/null
+++ b/third_party/rust/futures-0.1.29/src/future/from_err.rs
@@ -0,0 +1,35 @@
+use core::marker::PhantomData;
+
+use {Future, Poll, Async};
+
+/// Future for the `from_err` combinator, changing the error type of a future.
+///
+/// This is created by the `Future::from_err` method.
+#[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
+pub struct FromErr<A, E> where A: Future {
+    future: A,
+    f: PhantomData<E>
+}
+
+pub fn new<A, E>(future: A) -> FromErr<A, E>
+    where A: Future
+{
+    FromErr {
+        future: future,
+        f: PhantomData
+    }
+}
+
+impl<A:Future, E:From<A::Error>> Future for FromErr<A, E> {
+    type Item = A::Item;
+    type Error = E;
+
+    fn poll(&mut self) -> Poll<A::Item, E> {
+        let e = match self.future.poll() {
+            Ok(Async::NotReady) => return Ok(Async::NotReady),
+            other => other,
+        };
+        e.map_err(From::from)
+    }
+}