add with_timeout

embassy/src/executor/timer.rs

@@ -2,7 +2,7 @@ use core::future::Future;
 use core::marker::PhantomData;
 use core::pin::Pin;
 use core::task::{Context, Poll};
-use futures::Stream;
+use futures::{future::select, future::Either, pin_mut, Stream};
 
 use super::raw;
 use crate::time::{Duration, Instant};
@@ -31,6 +31,16 @@ impl crate::traits::delay::Delay for Delay {
     }
 }
 
+pub struct TimeoutError;
+pub async fn with_timeout<F: Future>(timeout: Duration, fut: F) -> Result<F::Output, TimeoutError> {
+    let timeout_fut = Timer::after(timeout);
+    pin_mut!(fut);
+    match select(fut, timeout_fut).await {
+        Either::Left((r, _)) => Ok(r),
+        Either::Right(_) => Err(TimeoutError),
+    }
+}
+
 /// A future that completes at a specified [Instant](struct.Instant.html).
 pub struct Timer {
     expires_at: Instant,

embassy/src/time/mod.rs

@@ -5,7 +5,7 @@ mod duration;
 mod instant;
 mod traits;
 
-pub use crate::executor::timer::{Delay, Ticker, Timer};
+pub use crate::executor::timer::{with_timeout, Delay, Ticker, TimeoutError, Timer};
 pub use duration::Duration;
 pub use instant::Instant;
 pub use traits::*;