Drop dummy_waker in favor of core::task::Waker::noop

.. now that we can.

Author: tnull

lightning-background-processor/src/lib.rs

@@ -337,7 +337,7 @@ pub(crate) mod futures_util {
 	use core::future::Future;
 	use core::marker::Unpin;
 	use core::pin::Pin;
-	use core::task::{Poll, RawWaker, RawWakerVTable, Waker};
+	use core::task::Poll;
 	pub(crate) struct Selector<
 		A: Future<Output = ()> + Unpin,
 		B: Future<Output = ()> + Unpin,
@@ -428,24 +428,6 @@ pub(crate) mod futures_util {
 		}
 	}
 
-	// If we want to poll a future without an async context to figure out if it has completed or
-	// not without awaiting, we need a Waker, which needs a vtable...we fill it with dummy values
-	// but sadly there's a good bit of boilerplate here.
-	fn dummy_waker_clone(_: *const ()) -> RawWaker {
-		RawWaker::new(core::ptr::null(), &DUMMY_WAKER_VTABLE)
-	}
-	fn dummy_waker_action(_: *const ()) {}
-
-	const DUMMY_WAKER_VTABLE: RawWakerVTable = RawWakerVTable::new(
-		dummy_waker_clone,
-		dummy_waker_action,
-		dummy_waker_action,
-		dummy_waker_action,
-	);
-	pub(crate) fn dummy_waker() -> Waker {
-		unsafe { Waker::from_raw(RawWaker::new(core::ptr::null(), &DUMMY_WAKER_VTABLE)) }
-	}
-
 	enum JoinerResult<E, F: Future<Output = Result<(), E>> + Unpin> {
 		Pending(Option<F>),
 		Ready(Result<(), E>),
@@ -558,7 +540,7 @@ pub(crate) mod futures_util {
 	}
 }
 use core::task;
-use futures_util::{dummy_waker, Joiner, OptionalSelector, Selector, SelectorOutput};
+use futures_util::{Joiner, OptionalSelector, Selector, SelectorOutput};
 
 /// Processes background events in a future.
 ///
@@ -950,7 +932,7 @@ where
 			// below. This will get it moving but won't block us for too long if the underlying
 			// future is actually async.
 			use core::future::Future;
-			let mut waker = dummy_waker();
+			let mut waker = task::Waker::noop();
 			let mut ctx = task::Context::from_waker(&mut waker);
 			match core::pin::Pin::new(&mut fut).poll(&mut ctx) {
 				task::Poll::Ready(res) => futures.set_a_res(res),
@@ -1168,7 +1150,7 @@ where
 				NETWORK_GRAPH_PERSISTENCE_KEY,
 				network_graph.encode(),
 			)
-			.await?;
+			.await?
 	}
 	Ok(())
 }
@@ -1178,7 +1160,7 @@ fn check_and_reset_sleeper<
 >(
 	fut: &mut SleepFuture, mut new_sleeper: impl FnMut() -> SleepFuture,
 ) -> Option<bool> {
-	let mut waker = dummy_waker();
+	let mut waker = task::Waker::noop();
 	let mut ctx = task::Context::from_waker(&mut waker);
 	match core::pin::Pin::new(&mut *fut).poll(&mut ctx) {
 		task::Poll::Ready(exit) => {

lightning/src/events/bump_transaction/sync.rs

@@ -12,12 +12,13 @@
 use core::future::Future;
 use core::ops::Deref;
 use core::task;
+use core::task::Waker;
 
 use crate::chain::chaininterface::BroadcasterInterface;
 use crate::chain::ClaimId;
 use crate::prelude::*;
 use crate::sign::SignerProvider;
-use crate::util::async_poll::{dummy_waker, AsyncResult, MaybeSend, MaybeSync};
+use crate::util::async_poll::{AsyncResult, MaybeSend, MaybeSync};
 use crate::util::logger::Logger;
 
 use bitcoin::{Psbt, ScriptBuf, Transaction, TxOut};
@@ -110,7 +111,7 @@ where
 			must_pay_to,
 			target_feerate_sat_per_1000_weight,
 		);
-		let mut waker = dummy_waker();
+		let mut waker = Waker::noop();
 		let mut ctx = task::Context::from_waker(&mut waker);
 		match fut.as_mut().poll(&mut ctx) {
 			task::Poll::Ready(result) => result,
@@ -124,7 +125,7 @@ where
 
 	fn sign_psbt(&self, psbt: Psbt) -> Result<Transaction, ()> {
 		let mut fut = self.wallet.sign_psbt(psbt);
-		let mut waker = dummy_waker();
+		let mut waker = Waker::noop();
 		let mut ctx = task::Context::from_waker(&mut waker);
 		match fut.as_mut().poll(&mut ctx) {
 			task::Poll::Ready(result) => result,
@@ -219,7 +220,7 @@ where
 	/// Handles all variants of [`BumpTransactionEvent`].
 	pub fn handle_event(&self, event: &BumpTransactionEvent) {
 		let mut fut = Box::pin(self.bump_transaction_event_handler.handle_event(event));
-		let mut waker = dummy_waker();
+		let mut waker = Waker::noop();
 		let mut ctx = task::Context::from_waker(&mut waker);
 		match fut.as_mut().poll(&mut ctx) {
 			task::Poll::Ready(result) => result,

lightning/src/util/async_poll.rs

@@ -13,7 +13,7 @@ use crate::prelude::*;
 use core::future::Future;
 use core::marker::Unpin;
 use core::pin::Pin;
-use core::task::{Context, Poll, RawWaker, RawWakerVTable, Waker};
+use core::task::{Context, Poll};
 
 pub(crate) enum ResultFuture<F: Future<Output = Result<(), E>>, E: Unpin> {
 	Pending(F),
@@ -70,27 +70,6 @@ impl<F: Future<Output = Result<(), E>> + Unpin, E: Unpin> Future for MultiResult
 	}
 }
 
-// If we want to poll a future without an async context to figure out if it has completed or
-// not without awaiting, we need a Waker, which needs a vtable...we fill it with dummy values
-// but sadly there's a good bit of boilerplate here.
-//
-// Waker::noop() would be preferable, but requires an MSRV of 1.85.
-fn dummy_waker_clone(_: *const ()) -> RawWaker {
-	RawWaker::new(core::ptr::null(), &DUMMY_WAKER_VTABLE)
-}
-fn dummy_waker_action(_: *const ()) {}
-
-const DUMMY_WAKER_VTABLE: RawWakerVTable = RawWakerVTable::new(
-	dummy_waker_clone,
-	dummy_waker_action,
-	dummy_waker_action,
-	dummy_waker_action,
-);
-
-pub(crate) fn dummy_waker() -> Waker {
-	unsafe { Waker::from_raw(RawWaker::new(core::ptr::null(), &DUMMY_WAKER_VTABLE)) }
-}
-
 /// A type alias for a future that returns a result of type T.
 #[cfg(feature = "std")]
 pub type AsyncResult<'a, T> = Pin<Box<dyn Future<Output = Result<T, ()>> + 'a + Send>>;

lightning/src/util/sweep.rs

@@ -39,8 +39,7 @@ use core::ops::Deref;
 use core::pin::Pin;
 use core::sync::atomic::{AtomicBool, Ordering};
 use core::task;
-
-use super::async_poll::dummy_waker;
+use core::task::Waker;
 
 /// The number of blocks we wait before we prune the tracked spendable outputs.
 pub const PRUNE_DELAY_BLOCKS: u32 = ARCHIVAL_DELAY_BLOCKS + ANTI_REORG_DELAY;
@@ -1042,7 +1041,7 @@ where
 	/// [`OutputSweeper::regenerate_and_broadcast_spend_if_necessary`].
 	pub fn regenerate_and_broadcast_spend_if_necessary(&self) -> Result<(), ()> {
 		let mut fut = Box::pin(self.sweeper.regenerate_and_broadcast_spend_if_necessary());
-		let mut waker = dummy_waker();
+		let mut waker = Waker::noop();
 		let mut ctx = task::Context::from_waker(&mut waker);
 		match fut.as_mut().poll(&mut ctx) {
 			task::Poll::Ready(result) => result,
@@ -1064,7 +1063,7 @@ where
 			exclude_static_outputs,
 			delay_until_height,
 		));
-		let mut waker = dummy_waker();
+		let mut waker = Waker::noop();
 		let mut ctx = task::Context::from_waker(&mut waker);
 		match fut.as_mut().poll(&mut ctx) {
 			task::Poll::Ready(result) => result,