feat: Add TokioTimer to rt::tokio module (#73)

Author: daxhuiberts

src/rt/mod.rs

@@ -4,4 +4,4 @@
 pub mod tokio;
 
 #[cfg(feature = "tokio")]
-pub use self::tokio::{TokioExecutor, TokioIo};
+pub use self::tokio::{TokioExecutor, TokioIo, TokioTimer};

src/rt/tokio.rs

@@ -4,9 +4,10 @@ use std::{
     future::Future,
     pin::Pin,
     task::{Context, Poll},
+    time::{Duration, Instant},
 };
 
-use hyper::rt::Executor;
+use hyper::rt::{Executor, Sleep, Timer};
 use pin_project_lite::pin_project;
 
 /// Future executor that utilises `tokio` threads.
@@ -24,6 +25,21 @@ pin_project! {
     }
 }
 
+/// A Timer that uses the tokio runtime.
+#[non_exhaustive]
+#[derive(Default, Clone, Debug)]
+pub struct TokioTimer;
+
+// Use TokioSleep to get tokio::time::Sleep to implement Unpin.
+// see https://docs.rs/tokio/latest/tokio/time/struct.Sleep.html
+pin_project! {
+    #[derive(Debug)]
+    struct TokioSleep {
+        #[pin]
+        inner: tokio::time::Sleep,
+    }
+}
+
 // ===== impl TokioExecutor =====
 
 impl<Fut> Executor<Fut> for TokioExecutor
@@ -190,6 +206,51 @@ where
     }
 }
 
+// ==== impl TokioTimer =====
+
+impl Timer for TokioTimer {
+    fn sleep(&self, duration: Duration) -> Pin<Box<dyn Sleep>> {
+        Box::pin(TokioSleep {
+            inner: tokio::time::sleep(duration),
+        })
+    }
+
+    fn sleep_until(&self, deadline: Instant) -> Pin<Box<dyn Sleep>> {
+        Box::pin(TokioSleep {
+            inner: tokio::time::sleep_until(deadline.into()),
+        })
+    }
+
+    fn reset(&self, sleep: &mut Pin<Box<dyn Sleep>>, new_deadline: Instant) {
+        if let Some(sleep) = sleep.as_mut().downcast_mut_pin::<TokioSleep>() {
+            sleep.reset(new_deadline)
+        }
+    }
+}
+
+impl TokioTimer {
+    /// Create a new TokioTimer
+    pub fn new() -> Self {
+        Self {}
+    }
+}
+
+impl Future for TokioSleep {
+    type Output = ();
+
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        self.project().inner.poll(cx)
+    }
+}
+
+impl Sleep for TokioSleep {}
+
+impl TokioSleep {
+    fn reset(self: Pin<&mut Self>, deadline: Instant) {
+        self.project().inner.as_mut().reset(deadline.into());
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::rt::TokioExecutor;