Merge pull request #1962 from TheBlueMatt/2023-01-bp-no-std

Use the user-provided `SleepFuture` for interval checks in `background-processor`

Author: TheBlueMatt

lightning-background-processor/Cargo.toml

@@ -15,11 +15,14 @@ rustdoc-args = ["--cfg", "docsrs"]
 
 [features]
 futures = [ "futures-util" ]
+std = ["lightning/std", "lightning-rapid-gossip-sync/std"]
+
+default = ["std"]
 
 [dependencies]
-bitcoin = "0.29.0"
-lightning = { version = "0.0.113", path = "../lightning", features = ["std"] }
-lightning-rapid-gossip-sync = { version = "0.0.113", path = "../lightning-rapid-gossip-sync" }
+bitcoin = { version = "0.29.0", default-features = false }
+lightning = { version = "0.0.113", path = "../lightning", default-features = false }
+lightning-rapid-gossip-sync = { version = "0.0.113", path = "../lightning-rapid-gossip-sync", default-features = false }
 futures-util = { version = "0.3", default-features = false, features = ["async-await-macro"], optional = true }
 
 [dev-dependencies]

lightning-background-processor/src/lib.rs

@@ -11,6 +11,11 @@
 
 #![cfg_attr(docsrs, feature(doc_auto_cfg))]
 
+#![cfg_attr(all(not(feature = "std"), not(test)), no_std)]
+
+#[cfg(any(test, feature = "std"))]
+extern crate core;
+
 #[macro_use] extern crate lightning;
 extern crate lightning_rapid_gossip_sync;
 
@@ -28,15 +33,22 @@ use lightning::util::events::{Event, EventHandler, EventsProvider};
 use lightning::util::logger::Logger;
 use lightning::util::persist::Persister;
 use lightning_rapid_gossip_sync::RapidGossipSync;
+use lightning::io;
+
+use core::ops::Deref;
+use core::time::Duration;
+
+#[cfg(feature = "std")]
 use std::sync::Arc;
-use std::sync::atomic::{AtomicBool, Ordering};
-use std::thread;
-use std::thread::JoinHandle;
-use std::time::{Duration, Instant};
-use std::ops::Deref;
+#[cfg(feature = "std")]
+use core::sync::atomic::{AtomicBool, Ordering};
+#[cfg(feature = "std")]
+use std::thread::{self, JoinHandle};
+#[cfg(feature = "std")]
+use std::time::Instant;
 
 #[cfg(feature = "futures")]
-use futures_util::{select_biased, future::FutureExt};
+use futures_util::{select_biased, future::FutureExt, task};
 
 /// `BackgroundProcessor` takes care of tasks that (1) need to happen periodically to keep
 /// Rust-Lightning running properly, and (2) either can or should be run in the background. Its
@@ -62,6 +74,7 @@ use futures_util::{select_biased, future::FutureExt};
 ///
 /// [`ChannelMonitor`]: lightning::chain::channelmonitor::ChannelMonitor
 /// [`Event`]: lightning::util::events::Event
+#[cfg(feature = "std")]
 #[must_use = "BackgroundProcessor will immediately stop on drop. It should be stored until shutdown."]
 pub struct BackgroundProcessor {
 	stop_thread: Arc<AtomicBool>,
@@ -207,15 +220,15 @@ macro_rules! define_run_body {
 	($persister: ident, $chain_monitor: ident, $process_chain_monitor_events: expr,
 	 $channel_manager: ident, $process_channel_manager_events: expr,
 	 $gossip_sync: ident, $peer_manager: ident, $logger: ident, $scorer: ident,
-	 $loop_exit_check: expr, $await: expr)
+	 $loop_exit_check: expr, $await: expr, $get_timer: expr, $timer_elapsed: expr)
 	=> { {
 		log_trace!($logger, "Calling ChannelManager's timer_tick_occurred on startup");
 		$channel_manager.timer_tick_occurred();
 
-		let mut last_freshness_call = Instant::now();
-		let mut last_ping_call = Instant::now();
-		let mut last_prune_call = Instant::now();
-		let mut last_scorer_persist_call = Instant::now();
+		let mut last_freshness_call = $get_timer(FRESHNESS_TIMER);
+		let mut last_ping_call = $get_timer(PING_TIMER);
+		let mut last_prune_call = $get_timer(FIRST_NETWORK_PRUNE_TIMER);
+		let mut last_scorer_persist_call = $get_timer(SCORER_PERSIST_TIMER);
 		let mut have_pruned = false;
 
 		loop {
@@ -237,9 +250,9 @@ macro_rules! define_run_body {
 
 			// We wait up to 100ms, but track how long it takes to detect being put to sleep,
 			// see `await_start`'s use below.
-			let await_start = Instant::now();
+			let mut await_start = $get_timer(1);
 			let updates_available = $await;
-			let await_time = await_start.elapsed();
+			let await_slow = $timer_elapsed(&mut await_start, 1);
 
 			if updates_available {
 				log_trace!($logger, "Persisting ChannelManager...");
@@ -251,12 +264,12 @@ macro_rules! define_run_body {
 				log_trace!($logger, "Terminating background processor.");
 				break;
 			}
-			if last_freshness_call.elapsed().as_secs() > FRESHNESS_TIMER {
+			if $timer_elapsed(&mut last_freshness_call, FRESHNESS_TIMER) {
 				log_trace!($logger, "Calling ChannelManager's timer_tick_occurred");
 				$channel_manager.timer_tick_occurred();
-				last_freshness_call = Instant::now();
+				last_freshness_call = $get_timer(FRESHNESS_TIMER);
 			}
-			if await_time > Duration::from_secs(1) {
+			if await_slow {
 				// On various platforms, we may be starved of CPU cycles for several reasons.
 				// E.g. on iOS, if we've been in the background, we will be entirely paused.
 				// Similarly, if we're on a desktop platform and the device has been asleep, we
@@ -271,40 +284,46 @@ macro_rules! define_run_body {
 				// peers.
 				log_trace!($logger, "100ms sleep took more than a second, disconnecting peers.");
 				$peer_manager.disconnect_all_peers();
-				last_ping_call = Instant::now();
-			} else if last_ping_call.elapsed().as_secs() > PING_TIMER {
+				last_ping_call = $get_timer(PING_TIMER);
+			} else if $timer_elapsed(&mut last_ping_call, PING_TIMER) {
 				log_trace!($logger, "Calling PeerManager's timer_tick_occurred");
 				$peer_manager.timer_tick_occurred();
-				last_ping_call = Instant::now();
+				last_ping_call = $get_timer(PING_TIMER);
 			}
 
 			// Note that we want to run a graph prune once not long after startup before
 			// falling back to our usual hourly prunes. This avoids short-lived clients never
 			// pruning their network graph. We run once 60 seconds after startup before
 			// continuing our normal cadence.
-			if last_prune_call.elapsed().as_secs() > if have_pruned { NETWORK_PRUNE_TIMER } else { FIRST_NETWORK_PRUNE_TIMER } {
+			if $timer_elapsed(&mut last_prune_call, if have_pruned { NETWORK_PRUNE_TIMER } else { FIRST_NETWORK_PRUNE_TIMER }) {
 				// The network graph must not be pruned while rapid sync completion is pending
 				if let Some(network_graph) = $gossip_sync.prunable_network_graph() {
-					log_trace!($logger, "Pruning and persisting network graph.");
-					network_graph.remove_stale_channels_and_tracking();
+					#[cfg(feature = "std")] {
+						log_trace!($logger, "Pruning and persisting network graph.");
+						network_graph.remove_stale_channels_and_tracking();
+					}
+					#[cfg(not(feature = "std"))] {
+						log_warn!($logger, "Not pruning network graph, consider enabling `std` or doing so manually with remove_stale_channels_and_tracking_with_time.");
+						log_trace!($logger, "Persisting network graph.");
+					}
 
 					if let Err(e) = $persister.persist_graph(network_graph) {
 						log_error!($logger, "Error: Failed to persist network graph, check your disk and permissions {}", e)
 					}
 
-					last_prune_call = Instant::now();
+					last_prune_call = $get_timer(NETWORK_PRUNE_TIMER);
 					have_pruned = true;
 				}
 			}
 
-			if last_scorer_persist_call.elapsed().as_secs() > SCORER_PERSIST_TIMER {
+			if $timer_elapsed(&mut last_scorer_persist_call, SCORER_PERSIST_TIMER) {
 				if let Some(ref scorer) = $scorer {
 					log_trace!($logger, "Persisting scorer");
 					if let Err(e) = $persister.persist_scorer(&scorer) {
 						log_error!($logger, "Error: Failed to persist scorer, check your disk and permissions {}", e)
 					}
 				}
-				last_scorer_persist_call = Instant::now();
+				last_scorer_persist_call = $get_timer(SCORER_PERSIST_TIMER);
 			}
 		}
 
@@ -334,6 +353,11 @@ macro_rules! define_run_body {
 /// future which outputs true, the loop will exit and this function's future will complete.
 ///
 /// See [`BackgroundProcessor::start`] for information on which actions this handles.
+///
+/// Requires the `futures` feature. Note that while this method is available without the `std`
+/// feature, doing so will skip calling [`NetworkGraph::remove_stale_channels_and_tracking`],
+/// you should call [`NetworkGraph::remove_stale_channels_and_tracking_with_time`] regularly
+/// manually instead.
 #[cfg(feature = "futures")]
 pub async fn process_events_async<
 	'a,
@@ -364,13 +388,13 @@ pub async fn process_events_async<
 	PM: 'static + Deref<Target = PeerManager<Descriptor, CMH, RMH, OMH, L, UMH>> + Send + Sync,
 	S: 'static + Deref<Target = SC> + Send + Sync,
 	SC: WriteableScore<'a>,
-	SleepFuture: core::future::Future<Output = bool>,
+	SleepFuture: core::future::Future<Output = bool> + core::marker::Unpin,
 	Sleeper: Fn(Duration) -> SleepFuture
 >(
 	persister: PS, event_handler: EventHandler, chain_monitor: M, channel_manager: CM,
 	gossip_sync: GossipSync<PGS, RGS, G, CA, L>, peer_manager: PM, logger: L, scorer: Option<S>,
 	sleeper: Sleeper,
-) -> Result<(), std::io::Error>
+) -> Result<(), io::Error>
 where
 	CA::Target: 'static + chain::Access,
 	CF::Target: 'static + chain::Filter,
@@ -411,9 +435,15 @@ where
 					false
 				}
 			}
+		}, |t| sleeper(Duration::from_secs(t)),
+		|fut: &mut SleepFuture, _| {
+			let mut waker = task::noop_waker();
+			let mut ctx = task::Context::from_waker(&mut waker);
+			core::pin::Pin::new(fut).poll(&mut ctx).is_ready()
 		})
 }
 
+#[cfg(feature = "std")]
 impl BackgroundProcessor {
 	/// Start a background thread that takes care of responsibilities enumerated in the [top-level
 	/// documentation].
@@ -522,7 +552,8 @@ impl BackgroundProcessor {
 			define_run_body!(persister, chain_monitor, chain_monitor.process_pending_events(&event_handler),
 				channel_manager, channel_manager.process_pending_events(&event_handler),
 				gossip_sync, peer_manager, logger, scorer, stop_thread.load(Ordering::Acquire),
-				channel_manager.await_persistable_update_timeout(Duration::from_millis(100)))
+				channel_manager.await_persistable_update_timeout(Duration::from_millis(100)),
+				|_| Instant::now(), |time: &Instant, dur| time.elapsed().as_secs() > dur)
 		});
 		Self { stop_thread: stop_thread_clone, thread_handle: Some(handle) }
 	}
@@ -568,13 +599,14 @@ impl BackgroundProcessor {
 	}
 }
 
+#[cfg(feature = "std")]
 impl Drop for BackgroundProcessor {
 	fn drop(&mut self) {
 		self.stop_and_join_thread().unwrap();
 	}
 }
 
-#[cfg(test)]
+#[cfg(all(feature = "std", test))]
 mod tests {
 	use bitcoin::blockdata::block::BlockHeader;
 	use bitcoin::blockdata::constants::genesis_block;

no-std-check/Cargo.toml

@@ -10,3 +10,4 @@ default = ["lightning/no-std", "lightning-invoice/no-std", "lightning-rapid-goss
 lightning = { path = "../lightning", default-features = false }
 lightning-invoice = { path = "../lightning-invoice", default-features = false }
 lightning-rapid-gossip-sync = { path = "../lightning-rapid-gossip-sync", default-features = false }
+lightning-background-processor = { path = "../lightning-background-processor", features = ["futures"], default-features = false }