Remove AwaitCanceled (#1375)

polkadot/network/Cargo.toml

@@ -19,7 +19,7 @@ sc-network = { git = "https://github.com/paritytech/substrate", branch = "master
 sc-network-gossip = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "master" }
-futures = "0.3.4"
+futures = "0.3.5"
 log = "0.4.8"
 exit-future = "0.2.0"
 futures-timer = "2.0"

polkadot/network/src/protocol/mod.rs

@@ -404,28 +404,6 @@ struct ConsensusNetworkingInstance {
 	_drop_signal: exit_future::Signal,
 }
 
-/// A utility future that resolves when the receiving end of a channel has hung up.
-///
-/// This is an `.await`-friendly interface around `poll_canceled`.
-// TODO: remove in favor of https://github.com/rust-lang/futures-rs/pull/2092/
-// once published.
-#[must_use = "futures do nothing unless you `.await` or poll them"]
-#[derive(Debug)]
-pub struct AwaitCanceled<'a, T> {
-	inner: &'a mut oneshot::Sender<T>,
-}
-
-impl<T> Future for AwaitCanceled<'_, T> {
-	type Output = ();
-
-	fn poll(
-		mut self: Pin<&mut Self>,
-		cx: &mut futures::task::Context<'_>,
-	) -> futures::task::Poll<()> {
-		self.inner.poll_canceled(cx)
-	}
-}
-
 /// Protocol configuration.
 #[derive(Default)]
 pub struct Config {
@@ -947,7 +925,7 @@ impl<Api, Sp, Gossip> Worker<Api, Sp, Gossip> where
 				self.executor.spawn(
 					"polkadot-fetch-pov-block",
 					async move {
-						let res = future::select(get_msg, AwaitCanceled { inner: &mut sender }).await;
+						let res = future::select(get_msg, sender.cancellation()).await;
 						if let Either::Left((pov_block, _)) = res {
 							let _ = sender.send(pov_block);
 						}
@@ -981,7 +959,7 @@ impl<Api, Sp, Gossip> Worker<Api, Sp, Gossip> where
 				self.executor.spawn(
 					"polkadot-fetch-erasure-chunk",
 					async move {
-						let res = future::select(get_msg, AwaitCanceled { inner: &mut sender }).await;
+						let res = future::select(get_msg, sender.cancellation()).await;
 						if let Either::Left((chunk, _)) = res {
 							let _ = sender.send(chunk);
 						}