1 files changed, 75 insertions, 0 deletions
diff --git a/third_party/rust/tokio-timer/src/interval.rs b/third_party/rust/tokio-timer/src/interval.rs
new file mode 100644
index 0000000000..019efe6a2d
--- /dev/null
+++ b/third_party/rust/tokio-timer/src/interval.rs
@@ -0,0 +1,75 @@
+use Delay;
+
+use clock;
+
+use futures::{Future, Poll, Stream};
+
+use std::time::{Duration, Instant};
+
+/// A stream representing notifications at fixed interval
+#[derive(Debug)]
+pub struct Interval {
+    /// Future that completes the next time the `Interval` yields a value.
+    delay: Delay,
+
+    /// The duration between values yielded by `Interval`.
+    duration: Duration,
+}
+
+impl Interval {
+    /// Create a new `Interval` that starts at `at` and yields every `duration`
+    /// interval after that.
+    ///
+    /// Note that when it starts, it produces item too.
+    ///
+    /// The `duration` argument must be a non-zero duration.
+    ///
+    /// # Panics
+    ///
+    /// This function panics if `duration` is zero.
+    pub fn new(at: Instant, duration: Duration) -> Interval {
+        assert!(
+            duration > Duration::new(0, 0),
+            "`duration` must be non-zero."
+        );
+
+        Interval::new_with_delay(Delay::new(at), duration)
+    }
+
+    /// Creates new `Interval` that yields with interval of `duration`.
+    ///
+    /// The function is shortcut for `Interval::new(Instant::now() + duration, duration)`.
+    ///
+    /// The `duration` argument must be a non-zero duration.
+    ///
+    /// # Panics
+    ///
+    /// This function panics if `duration` is zero.
+    pub fn new_interval(duration: Duration) -> Interval {
+        Interval::new(clock::now() + duration, duration)
+    }
+
+    pub(crate) fn new_with_delay(delay: Delay, duration: Duration) -> Interval {
+        Interval { delay, duration }
+    }
+}
+
+impl Stream for Interval {
+    type Item = Instant;
+    type Error = ::Error;
+
+    fn poll(&mut self) -> Poll<Option<Self::Item>, Self::Error> {
+        // Wait for the delay to be done
+        let _ = try_ready!(self.delay.poll());
+
+        // Get the `now` by looking at the `delay` deadline
+        let now = self.delay.deadline();
+
+        // The next interval value is `duration` after the one that just
+        // yielded.
+        self.delay.reset(now + self.duration);
+
+        // Return the current instant
+        Ok(Some(now).into())
+    }
+}