Drop Deref indirection for UtxoSource

Reduces generics and verbosity across the codebase, should provide equivalent
behavior.

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: valentinewallace

lightning-block-sync/src/gossip.rs

@@ -42,6 +42,20 @@ pub trait UtxoSource: BlockSource + 'static {
 	) -> impl Future<Output = BlockSourceResult<bool>> + Send + 'a;
 }
 
+impl<T: UtxoSource + ?Sized, U: Deref<Target = T> + Send + Sync + 'static> UtxoSource for U {
+	fn get_block_hash_by_height<'a>(
+		&'a self, block_height: u32,
+	) -> impl Future<Output = BlockSourceResult<BlockHash>> + Send + 'a {
+		self.deref().get_block_hash_by_height(block_height)
+	}
+
+	fn is_output_unspent<'a>(
+		&'a self, outpoint: OutPoint,
+	) -> impl Future<Output = BlockSourceResult<bool>> + Send + 'a {
+		self.deref().is_output_unspent(outpoint)
+	}
+}
+
 #[cfg(feature = "tokio")]
 /// A trivial [`FutureSpawner`] which delegates to `tokio::spawn`.
 pub struct TokioSpawner;
@@ -129,21 +143,15 @@ impl<
 /// value of 1024 should more than suffice), and ensure you have sufficient file descriptors
 /// available on both Bitcoin Core and your LDK application for each request to hold its own
 /// connection.
-pub struct GossipVerifier<S: FutureSpawner, Blocks: Deref + Send + Sync + 'static + Clone>
-where
-	Blocks::Target: UtxoSource,
-{
+pub struct GossipVerifier<S: FutureSpawner, Blocks: UtxoSource + Clone> {
 	source: Blocks,
 	spawn: S,
 	block_cache: Arc<Mutex<VecDeque<(u32, Block)>>>,
 }
 
 const BLOCK_CACHE_SIZE: usize = 5;
 
-impl<S: FutureSpawner, Blocks: Deref + Send + Sync + Clone> GossipVerifier<S, Blocks>
-where
-	Blocks::Target: UtxoSource,
-{
+impl<S: FutureSpawner, Blocks: UtxoSource + Clone> GossipVerifier<S, Blocks> {
 	/// Constructs a new [`GossipVerifier`] for use in a [`P2PGossipSync`].
 	///
 	/// [`P2PGossipSync`]: lightning::routing::gossip::P2PGossipSync
@@ -239,10 +247,7 @@ where
 	}
 }
 
-impl<S: FutureSpawner, Blocks: Deref + Send + Sync + Clone> UtxoLookup for GossipVerifier<S, Blocks>
-where
-	Blocks::Target: UtxoSource,
-{
+impl<S: FutureSpawner, Blocks: UtxoSource + Clone> UtxoLookup for GossipVerifier<S, Blocks> {
 	fn get_utxo(&self, _chain_hash: &ChainHash, scid: u64, notifier: Arc<Notifier>) -> UtxoResult {
 		let res = UtxoFuture::new(notifier);
 		let fut = res.clone();

lightning-block-sync/src/init.rs

@@ -11,20 +11,15 @@ use bitcoin::network::Network;
 use lightning::chain;
 use lightning::chain::BestBlock;
 
-use std::ops::Deref;
-
 /// Returns a validated block header of the source's best chain tip.
 ///
 /// Upon success, the returned header can be used to initialize [`SpvClient`]. Useful during a fresh
 /// start when there are no chain listeners to sync yet.
 ///
 /// [`SpvClient`]: crate::SpvClient
-pub async fn validate_best_block_header<B: Deref>(
-	block_source: B,
-) -> BlockSourceResult<ValidatedBlockHeader>
-where
-	B::Target: BlockSource,
-{
+pub async fn validate_best_block_header<B: BlockSource + ?Sized>(
+	block_source: &B,
+) -> BlockSourceResult<ValidatedBlockHeader> {
 	let (best_block_hash, best_block_height) = block_source.get_best_block().await?;
 	block_source.get_header(&best_block_hash, best_block_height).await?.validate(best_block_hash)
 }
@@ -64,7 +59,7 @@ where
 /// use lightning::io::Cursor;
 ///
 /// async fn init_sync<
-/// 	B: BlockSource,
+/// 	B: BlockSource + 'static,
 /// 	ES: EntropySource,
 /// 	NS: NodeSigner,
 /// 	SP: SignerProvider,
@@ -139,17 +134,14 @@ where
 /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 /// [`ChannelMonitor`]: lightning::chain::channelmonitor::ChannelMonitor
 pub async fn synchronize_listeners<
-	B: Deref + Sized + Send + Sync,
+	B: BlockSource + 'static,
 	C: Cache,
 	L: chain::Listen + ?Sized,
 >(
-	block_source: B, network: Network, header_cache: &mut C,
+	block_source: &B, network: Network, header_cache: &mut C,
 	mut chain_listeners: Vec<(BlockHash, &L)>,
-) -> BlockSourceResult<ValidatedBlockHeader>
-where
-	B::Target: BlockSource,
-{
-	let best_header = validate_best_block_header(&*block_source).await?;
+) -> BlockSourceResult<ValidatedBlockHeader> {
+	let best_header = validate_best_block_header(block_source).await?;
 
 	// Fetch the header for the block hash paired with each listener.
 	let mut chain_listeners_with_old_headers = Vec::new();

lightning-block-sync/src/lib.rs

@@ -83,6 +83,26 @@ pub trait BlockSource: Sync + Send {
 	) -> impl Future<Output = BlockSourceResult<(BlockHash, Option<u32>)>> + Send + 'a;
 }
 
+impl<T: BlockSource + ?Sized + 'static, B: Deref<Target = T> + Sync + Send> BlockSource for B {
+	fn get_header<'a>(
+		&'a self, header_hash: &'a BlockHash, height_hint: Option<u32>,
+	) -> impl Future<Output = BlockSourceResult<BlockHeaderData>> + Send + 'a {
+		self.deref().get_header(header_hash, height_hint)
+	}
+
+	fn get_block<'a>(
+		&'a self, header_hash: &'a BlockHash,
+	) -> impl Future<Output = BlockSourceResult<BlockData>> + Send + 'a {
+		self.deref().get_block(header_hash)
+	}
+
+	fn get_best_block<'a>(
+		&'a self,
+	) -> impl Future<Output = BlockSourceResult<(BlockHash, Option<u32>)>> + Send + 'a {
+		self.deref().get_best_block()
+	}
+}
+
 /// Result type for `BlockSource` requests.
 pub type BlockSourceResult<T> = Result<T, BlockSourceError>;
 

lightning-block-sync/src/poll.rs

@@ -7,7 +7,6 @@ use bitcoin::network::Network;
 use lightning::chain::BestBlock;
 
 use std::future::Future;
-use std::ops::Deref;
 
 /// The `Poll` trait defines behavior for polling block sources for a chain tip and retrieving
 /// related chain data. It serves as an adapter for `BlockSource`.
@@ -195,12 +194,12 @@ mod sealed {
 ///
 /// Other `Poll` implementations should be built using `ChainPoller` as it provides the simplest way
 /// of validating chain data and checking consistency.
-pub struct ChainPoller<B: Deref<Target = T> + Sized + Send + Sync, T: BlockSource + ?Sized> {
+pub struct ChainPoller<B: BlockSource> {
 	block_source: B,
 	network: Network,
 }
 
-impl<B: Deref<Target = T> + Sized + Send + Sync, T: BlockSource + ?Sized> ChainPoller<B, T> {
+impl<B: BlockSource> ChainPoller<B> {
 	/// Creates a new poller for the given block source.
 	///
 	/// If the `network` parameter is mainnet, then the difficulty between blocks is checked for
@@ -210,9 +209,7 @@ impl<B: Deref<Target = T> + Sized + Send + Sync, T: BlockSource + ?Sized> ChainP
 	}
 }
 
-impl<B: Deref<Target = T> + Sized + Send + Sync, T: BlockSource + ?Sized> Poll
-	for ChainPoller<B, T>
-{
+impl<B: BlockSource> Poll for ChainPoller<B> {
 	fn poll_chain_tip<'a>(
 		&'a self, best_known_chain_tip: ValidatedBlockHeader,
 	) -> impl Future<Output = BlockSourceResult<ChainTip>> + Send + 'a {