Reduce io::TimeoutFuture to futures_timer::TryFutureExt (#113)

src/io/timeout.rs

@@ -1,12 +1,9 @@
-use std::pin::Pin;
 use std::time::Duration;
 
-use futures_timer::Delay;
-use pin_utils::unsafe_pinned;
+use futures_timer::TryFutureExt;
 
 use crate::future::Future;
 use crate::io;
-use crate::task::{Context, Poll};
 
 /// Awaits an I/O future or times out after a duration of time.
 ///
@@ -33,39 +30,5 @@ pub async fn timeout<F, T>(dur: Duration, f: F) -> io::Result<T>
 where
     F: Future<Output = io::Result<T>>,
 {
-    let f = TimeoutFuture {
-        future: f,
-        delay: Delay::new(dur),
-    };
-    f.await
-}
-
-struct TimeoutFuture<F> {
-    future: F,
-    delay: Delay,
-}
-
-impl<F> TimeoutFuture<F> {
-    unsafe_pinned!(future: F);
-    unsafe_pinned!(delay: Delay);
-}
-
-impl<F, T> Future for TimeoutFuture<F>
-where
-    F: Future<Output = io::Result<T>>,
-{
-    type Output = F::Output;
-
-    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-        match self.as_mut().future().poll(cx) {
-            Poll::Ready(v) => Poll::Ready(v),
-            Poll::Pending => match self.delay().poll(cx) {
-                Poll::Ready(_) => Poll::Ready(Err(io::Error::new(
-                    io::ErrorKind::TimedOut,
-                    "I/O operation has timed out",
-                ))),
-                Poll::Pending => Poll::Pending,
-            },
-        }
-    }
+    f.timeout(dur).await
 }