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Add AChainMonitor trait and use it in background processor
Public commit record
73/100 · Adequate
What the developer wrote
Authored by Joost Jager
Add AChainMonitor trait and use it in background processor
Add a new `AChainMonitor` trait following the same pattern as
`AChannelManager`. This trait provides associated types for all
generic parameters of `ChainMonitor` and a `get_cm()` method to
access the underlying `ChainMonitor`.
Update the background processor to use `AChainMonitor` trait bounds
instead of spelling out the full `ChainMonitor` generic parameters.
This simplifies the function signatures by removing 5-6 explicit
generic parameters (CF, T, F, P, ES) per function.
This is preparation for adding a flush method to the AChainMonitor
trait.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
✓ Specific, descriptive subject✓ Names a concrete action or component✓ Provides detailed explanatory context
What changed, and why it matters
This commit is a pure internal refactoring in the Lightning Dev Kit Rust library. It introduces a new helper trait called AChainMonitor that wraps the existing ChainMonitor type, and updates background-processor functions to use that trait instead of listing many generic type parameters directly. There is no change to user-visible behavior, no bug fix, and no security-sensitive logic change.
Recommended action
No security action required. Treat as normal code-quality refactoring.
Security signals we found
No strong security signals were identified.
Evidence from the diff
The patch adds an AChainMonitor trait in lightning/src/chain/chainmonitor.rs with associated types for all ChainMonitor generic parameters (Signer, Filter, Broadcaster, FeeEstimator, Logger, Persister, PersisterTarget, EntropySource) and a get_cm() accessor. It implements AChainMonitor for ChainMonitor. In lightning-background-processor/src/lib.rs, public async functions and BackgroundProcessor::start replace explicit ChainMonitor<…> bounds with AChainMonitor trait bounds, and chain_monitor. calls become chain_monitor.get_cm().. The commit message explicitly states this is preparation for adding a flush method later.
Changed components
lightning/src/chain/chainmonitor.rslightning-background-processor/src/lib.rsInspect captured patch +118 / −43
diff --git a/lightning-background-processor/src/lib.rs b/lightning-background-processor/src/lib.rs
index 26e8fc6..bb99d65 100644
--- a/lightning-background-processor/src/lib.rs
+++ b/lightning-background-processor/src/lib.rs
@@ -30,9 +30,11 @@ mod fwd_batch;
use fwd_batch::BatchDelay;
+#[cfg(not(c_bindings))]
use lightning::chain;
+#[cfg(not(c_bindings))]
use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
-use lightning::chain::chainmonitor::{ChainMonitor, Persist};
+use lightning::chain::chainmonitor::AChainMonitor;
#[cfg(feature = "std")]
use lightning::events::EventHandler;
#[cfg(feature = "std")]
@@ -50,9 +52,9 @@ use lightning::onion_message::messenger::AOnionMessenger;
use lightning::routing::gossip::{NetworkGraph, P2PGossipSync};
use lightning::routing::scoring::{ScoreUpdate, WriteableScore};
use lightning::routing::utxo::UtxoLookup;
-use lightning::sign::{
- ChangeDestinationSource, ChangeDestinationSourceSync, EntropySource, OutputSpender,
-};
+#[cfg(not(c_bindings))]
+use lightning::sign::EntropySource;
+use lightning::sign::{ChangeDestinationSource, ChangeDestinationSourceSync, OutputSpender};
#[cfg(not(c_bindings))]
use lightning::util::async_poll::MaybeSend;
use lightning::util::logger::Logger;
@@ -118,6 +120,7 @@ use alloc::vec::Vec;
///
/// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
/// [`ChannelManager::timer_tick_occurred`]: lightning::ln::channelmanager::ChannelManager::timer_tick_occurred
+/// [`ChainMonitor::rebroadcast_pending_claims`]: lightning::chain::chainmonitor::ChainMonitor::rebroadcast_pending_claims
/// [`ChannelMonitor`]: lightning::chain::channelmonitor::ChannelMonitor
/// [`Event`]: lightning::events::Event
/// [`PeerManager::timer_tick_occurred`]: lightning::ln::peer_handler::PeerManager::timer_tick_occurred
@@ -923,16 +926,11 @@ use futures_util::{dummy_waker, Joiner, OptionalSelector, Selector, SelectorOutp
pub async fn process_events_async<
'a,
UL: UtxoLookup,
- CF: chain::Filter,
- T: BroadcasterInterface,
- F: FeeEstimator,
G: Deref<Target = NetworkGraph<L>>,
L: Logger,
- P: Deref,
EventHandlerFuture: core::future::Future<Output = Result<(), ReplayEvent>>,
EventHandler: Fn(Event) -> EventHandlerFuture,
- ES: EntropySource,
- M: Deref<Target = ChainMonitor<<CM::Target as AChannelManager>::Signer, CF, T, F, L, P, ES>>,
+ M: Deref,
CM: Deref,
OM: Deref,
PGS: Deref<Target = P2PGossipSync<G, UL, L>>,
@@ -942,7 +940,17 @@ pub async fn process_events_async<
D: Deref,
O: OutputSpender,
K: KVStore,
- OS: Deref<Target = OutputSweeper<T, D, F, CF, K, L, O>>,
+ OS: Deref<
+ Target = OutputSweeper<
+ <M::Target as AChainMonitor>::Broadcaster,
+ D,
+ <M::Target as AChainMonitor>::FeeEstimator,
+ <M::Target as AChainMonitor>::Filter,
+ K,
+ L,
+ O,
+ >,
+ >,
S: Deref<Target = SC>,
SC: for<'b> WriteableScore<'b>,
SleepFuture: core::future::Future<Output = bool> + core::marker::Unpin,
@@ -955,7 +963,7 @@ pub async fn process_events_async<
sleeper: Sleeper, mobile_interruptable_platform: bool, fetch_time: FetchTime,
) -> Result<(), lightning::io::Error>
where
- P::Target: Persist<<CM::Target as AChannelManager>::Signer>,
+ M::Target: AChainMonitor<Signer = <CM::Target as AChannelManager>::Signer, Logger = L>,
CM::Target: AChannelManager,
OM::Target: AOnionMessenger,
PM::Target: APeerManager,
@@ -1004,7 +1012,7 @@ where
log_trace!(logger, "Calling ChannelManager's timer_tick_occurred on startup");
channel_manager.get_cm().timer_tick_occurred();
log_trace!(logger, "Rebroadcasting monitor's pending claims on startup");
- chain_monitor.rebroadcast_pending_claims();
+ chain_monitor.get_cm().rebroadcast_pending_claims();
let mut last_freshness_call = sleeper(FRESHNESS_TIMER);
let mut last_onion_message_handler_call = sleeper(ONION_MESSAGE_HANDLER_TIMER);
@@ -1022,7 +1030,7 @@ where
loop {
channel_manager.get_cm().process_pending_events_async(async_event_handler).await;
- chain_monitor.process_pending_events_async(async_event_handler).await;
+ chain_monitor.get_cm().process_pending_events_async(async_event_handler).await;
if let Some(om) = &onion_messenger {
om.get_om().process_pending_events_async(async_event_handler).await
}
@@ -1072,7 +1080,7 @@ where
let fut = Selector {
a: sleeper(sleep_delay),
b: channel_manager.get_cm().get_event_or_persistence_needed_future(),
- c: chain_monitor.get_update_future(),
+ c: chain_monitor.get_cm().get_update_future(),
d: om_fut,
e: lm_fut,
f: gv_fut,
@@ -1164,7 +1172,7 @@ where
};
if archive_timer_elapsed {
log_trace!(logger, "Archiving stale ChannelMonitors.");
- chain_monitor.archive_fully_resolved_channel_monitors();
+ chain_monitor.get_cm().archive_fully_resolved_channel_monitors();
have_archived = true;
log_trace!(logger, "Archived stale ChannelMonitors.");
}
@@ -1354,7 +1362,7 @@ where
match check_and_reset_sleeper(&mut last_rebroadcast_call, || sleeper(REBROADCAST_TIMER)) {
Some(false) => {
log_trace!(logger, "Rebroadcasting monitor's pending claims");
- chain_monitor.rebroadcast_pending_claims();
+ chain_monitor.get_cm().rebroadcast_pending_claims();
},
Some(true) => break,
None => {},
@@ -1416,16 +1424,11 @@ fn check_and_reset_sleeper<
/// synchronous background persistence.
pub async fn process_events_async_with_kv_store_sync<
UL: UtxoLookup,
- CF: chain::Filter,
- T: BroadcasterInterface,
- F: FeeEstimator,
G: Deref<Target = NetworkGraph<L>>,
L: Logger,
- P: Deref,
EventHandlerFuture: core::future::Future<Output = Result<(), ReplayEvent>>,
EventHandler: Fn(Event) -> EventHandlerFuture,
- ES: EntropySource,
- M: Deref<Target = ChainMonitor<<CM::Target as AChannelManager>::Signer, CF, T, F, L, P, ES>>,
+ M: Deref,
CM: Deref,
OM: Deref,
PGS: Deref<Target = P2PGossipSync<G, UL, L>>,
@@ -1435,7 +1438,17 @@ pub async fn process_events_async_with_kv_store_sync<
D: Deref,
O: OutputSpender,
K: Deref,
- OS: Deref<Target = OutputSweeperSync<T, D, F, CF, K, L, O>>,
+ OS: Deref<
+ Target = OutputSweeperSync<
+ <M::Target as AChainMonitor>::Broadcaster,
+ D,
+ <M::Target as AChainMonitor>::FeeEstimator,
+ <M::Target as AChainMonitor>::Filter,
+ K,
+ L,
+ O,
+ >,
+ >,
S: Deref<Target = SC>,
SC: for<'b> WriteableScore<'b>,
SleepFuture: core::future::Future<Output = bool> + core::marker::Unpin,
@@ -1448,7 +1461,7 @@ pub async fn process_events_async_with_kv_store_sync<
sleeper: Sleeper, mobile_interruptable_platform: bool, fetch_time: FetchTime,
) -> Result<(), lightning::io::Error>
where
- P::Target: Persist<<CM::Target as AChannelManager>::Signer>,
+ M::Target: AChainMonitor<Signer = <CM::Target as AChannelManager>::Signer, Logger = L>,
CM::Target: AChannelManager,
OM::Target: AOnionMessenger,
PM::Target: APeerManager,
@@ -1523,20 +1536,10 @@ impl BackgroundProcessor {
pub fn start<
'a,
UL: 'static + UtxoLookup,
- CF: 'static + chain::Filter,
- T: 'static + BroadcasterInterface,
- F: 'static + FeeEstimator + Send,
G: 'static + Deref<Target = NetworkGraph<L>>,
L: 'static + Deref + Send,
- P: 'static + Deref,
EH: 'static + EventHandler + Send,
- ES: 'static + EntropySource + Send,
- M: 'static
- + Deref<
- Target = ChainMonitor<<CM::Target as AChannelManager>::Signer, CF, T, F, L, P, ES>,
- >
- + Send
- + Sync,
+ M: 'static + Deref + Send + Sync,
CM: 'static + Deref + Send,
OM: 'static + Deref + Send,
PGS: 'static + Deref<Target = P2PGossipSync<G, UL, L>> + Send,
@@ -1548,7 +1551,19 @@ impl BackgroundProcessor {
D: 'static + Deref,
O: 'static + OutputSpender,
K: 'static + Deref + Send,
- OS: 'static + Deref<Target = OutputSweeperSync<T, D, F, CF, K, L, O>> + Send,
+ OS: 'static
+ + Deref<
+ Target = OutputSweeperSync<
+ <M::Target as AChainMonitor>::Broadcaster,
+ D,
+ <M::Target as AChainMonitor>::FeeEstimator,
+ <M::Target as AChainMonitor>::Filter,
+ K,
+ L,
+ O,
+ >,
+ >
+ + Send,
>(
kv_store: K, event_handler: EH, chain_monitor: M, channel_manager: CM,
onion_messenger: Option<OM>, gossip_sync: GossipSync<PGS, RGS, G, UL, L>, peer_manager: PM,
@@ -1556,7 +1571,7 @@ impl BackgroundProcessor {
) -> Self
where
L::Target: 'static + Logger,
- P::Target: 'static + Persist<<CM::Target as AChannelManager>::Signer>,
+ M::Target: AChainMonitor<Signer = <CM::Target as AChannelManager>::Signer, Logger = L>,
CM::Target: AChannelManager,
OM::Target: AOnionMessenger,
PM::Target: APeerManager,
@@ -1596,7 +1611,7 @@ impl BackgroundProcessor {
log_trace!(logger, "Calling ChannelManager's timer_tick_occurred on startup");
channel_manager.get_cm().timer_tick_occurred();
log_trace!(logger, "Rebroadcasting monitor's pending claims on startup");
- chain_monitor.rebroadcast_pending_claims();
+ chain_monitor.get_cm().rebroadcast_pending_claims();
let mut last_freshness_call = Instant::now();
let mut last_onion_message_handler_call = Instant::now();
@@ -1615,7 +1630,7 @@ impl BackgroundProcessor {
loop {
channel_manager.get_cm().process_pending_events(&event_handler);
- chain_monitor.process_pending_events(&event_handler);
+ chain_monitor.get_cm().process_pending_events(&event_handler);
if let Some(om) = &onion_messenger {
om.get_om().process_pending_events(&event_handler)
};
@@ -1648,7 +1663,7 @@ impl BackgroundProcessor {
let gv_fut = gossip_sync.validation_completion_future();
let always_futures = [
channel_manager.get_cm().get_event_or_persistence_needed_future(),
- chain_monitor.get_update_future(),
+ chain_monitor.get_cm().get_update_future(),
];
let futures = always_futures.into_iter().chain(om_fut).chain(lm_fut).chain(gv_fut);
let sleeper = Sleeper::from_futures(futures);
@@ -1701,7 +1716,7 @@ impl BackgroundProcessor {
let archive_timer_elapsed = last_archive_call.elapsed() > archive_timer;
if archive_timer_elapsed {
log_trace!(logger, "Archiving stale ChannelMonitors.");
- chain_monitor.archive_fully_resolved_channel_monitors();
+ chain_monitor.get_cm().archive_fully_resolved_channel_monitors();
have_archived = true;
last_archive_call = Instant::now();
log_trace!(logger, "Archived stale ChannelMonitors.");
@@ -1786,7 +1801,7 @@ impl BackgroundProcessor {
}
if last_rebroadcast_call.elapsed() > REBROADCAST_TIMER {
log_trace!(logger, "Rebroadcasting monitor's pending claims");
- chain_monitor.rebroadcast_pending_claims();
+ chain_monitor.get_cm().rebroadcast_pending_claims();
last_rebroadcast_call = Instant::now();
}
}
diff --git a/lightning/src/chain/chainmonitor.rs b/lightning/src/chain/chainmonitor.rs
index 2db3473..17693f8 100644
--- a/lightning/src/chain/chainmonitor.rs
+++ b/lightning/src/chain/chainmonitor.rs
@@ -1488,6 +1488,66 @@ where
}
}
+/// A trivial trait which describes any [`ChainMonitor`].
+///
+/// This is not exported to bindings users as general cover traits aren't useful in other
+/// languages.
+pub trait AChainMonitor {
+ /// A type implementing [`EcdsaChannelSigner`].
+ type Signer: EcdsaChannelSigner + Sized;
+ /// A type implementing [`chain::Filter`].
+ type Filter: chain::Filter;
+ /// A type implementing [`BroadcasterInterface`].
+ type Broadcaster: BroadcasterInterface;
+ /// A type implementing [`FeeEstimator`].
+ type FeeEstimator: FeeEstimator;
+ /// A type implementing [`Logger`].
+ type Logger: Logger;
+ /// A type that derefs to [`Persist`].
+ type Persister: Deref<Target = Self::PersisterTarget>;
+ /// The target of [`Self::Persister`].
+ type PersisterTarget: Persist<Self::Signer> + ?Sized;
+ /// A type implementing [`EntropySource`].
+ type EntropySource: EntropySource;
+ /// Returns a reference to the actual [`ChainMonitor`] object.
+ fn get_cm(
+ &self,
+ ) -> &ChainMonitor<
+ Self::Signer,
+ Self::Filter,
+ Self::Broadcaster,
+ Self::FeeEstimator,
+ Self::Logger,
+ Self::Persister,
+ Self::EntropySource,
+ >;
+}
+
+impl<
+ ChannelSigner: EcdsaChannelSigner,
+ C: chain::Filter,
+ T: BroadcasterInterface,
+ F: FeeEstimator,
+ L: Logger,
+ P: Deref,
+ ES: EntropySource,
+ > AChainMonitor for ChainMonitor<ChannelSigner, C, T, F, L, P, ES>
+where
+ P::Target: Persist<ChannelSigner>,
+{
+ type Signer = ChannelSigner;
+ type Filter = C;
+ type Broadcaster = T;
+ type FeeEstimator = F;
+ type Logger = L;
+ type Persister = P;
+ type PersisterTarget = P::Target;
+ type EntropySource = ES;
+ fn get_cm(&self) -> &ChainMonitor<ChannelSigner, C, T, F, L, P, ES> {
+ self
+ }
+}
+
#[cfg(test)]
mod tests {
use crate::chain::channelmonitor::ANTI_REORG_DELAY;
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