Avoid dyn indirection in gossip validation

In the next commit we'll update `rust-lightning` with the
`Pin<Box<dyn ...>>` pattern dropped in favor of native async traits
(with `impl Future...`). In anticipation of those traits becoming
not-object-safe here we drop the dyn indirection that exists in our
gossip validation.

Author: TheBlueMatt

src/chain/bitcoind.rs

@@ -12,7 +12,7 @@ use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};
 
 use base64::prelude::BASE64_STANDARD;
 use base64::Engine;
-use bitcoin::{BlockHash, FeeRate, Network, Transaction, Txid};
+use bitcoin::{BlockHash, FeeRate, Network, OutPoint, Transaction, Txid};
 use lightning::chain::chaininterface::ConfirmationTarget as LdkConfirmationTarget;
 use lightning::chain::{BestBlock, Listen};
 use lightning::util::ser::Writeable;
@@ -117,7 +117,7 @@ impl BitcoindChainSource {
 		}
 	}
 
-	pub(super) fn as_utxo_source(&self) -> Arc<dyn UtxoSource> {
+	pub(super) fn as_utxo_source(&self) -> UtxoSourceClient {
 		self.api_client.utxo_source()
 	}
 
@@ -639,6 +639,65 @@ impl BitcoindChainSource {
 	}
 }
 
+#[derive(Clone)]
+pub(crate) enum UtxoSourceClient {
+	Rpc(Arc<RpcClient>),
+	Rest(Arc<RestClient>),
+}
+
+impl std::ops::Deref for UtxoSourceClient {
+	type Target = Self;
+	fn deref(&self) -> &Self {
+		self
+	}
+}
+
+impl BlockSource for UtxoSourceClient {
+	fn get_header<'a>(
+		&'a self, header_hash: &'a BlockHash, height_hint: Option<u32>,
+	) -> AsyncBlockSourceResult<'a, BlockHeaderData> {
+		match self {
+			Self::Rpc(client) => client.get_header(header_hash, height_hint),
+			Self::Rest(client) => client.get_header(header_hash, height_hint),
+		}
+	}
+
+	fn get_block<'a>(
+		&'a self, header_hash: &'a BlockHash,
+	) -> AsyncBlockSourceResult<'a, BlockData> {
+		match self {
+			Self::Rpc(client) => client.get_block(header_hash),
+			Self::Rest(client) => client.get_block(header_hash),
+		}
+	}
+
+	fn get_best_block(&self) -> AsyncBlockSourceResult<'_, (BlockHash, Option<u32>)> {
+		match self {
+			Self::Rpc(client) => client.get_best_block(),
+			Self::Rest(client) => client.get_best_block(),
+		}
+	}
+}
+
+
+impl UtxoSource for UtxoSourceClient {
+	fn get_block_hash_by_height<'a>(
+		&'a self, block_height: u32,
+	) -> AsyncBlockSourceResult<'a, BlockHash> {
+		match self {
+			Self::Rpc(client) => client.get_block_hash_by_height(block_height),
+			Self::Rest(client) => client.get_block_hash_by_height(block_height),
+		}
+	}
+
+	fn is_output_unspent<'a>(&'a self, outpoint: OutPoint) -> AsyncBlockSourceResult<'a, bool> {
+		match self {
+			Self::Rpc(client) => client.is_output_unspent(outpoint),
+			Self::Rest(client) => client.is_output_unspent(outpoint),
+		}
+	}
+}
+
 pub enum BitcoindClient {
 	Rpc {
 		rpc_client: Arc<RpcClient>,
@@ -700,12 +759,10 @@ impl BitcoindClient {
 		}
 	}
 
-	pub(crate) fn utxo_source(&self) -> Arc<dyn UtxoSource> {
+	fn utxo_source(&self) -> UtxoSourceClient {
 		match self {
-			BitcoindClient::Rpc { rpc_client, .. } => Arc::clone(rpc_client) as Arc<dyn UtxoSource>,
-			BitcoindClient::Rest { rest_client, .. } => {
-				Arc::clone(rest_client) as Arc<dyn UtxoSource>
-			},
+			Self::Rpc { rpc_client, .. } => UtxoSourceClient::Rpc(Arc::clone(&rpc_client)),
+			Self::Rest { rest_client, .. } => UtxoSourceClient::Rest(Arc::clone(&rest_client)),
 		}
 	}
 

src/chain/mod.rs

@@ -5,7 +5,7 @@
 // http://opensource.org/licenses/MIT>, at your option. You may not use this file except in
 // accordance with one or both of these licenses.
 
-mod bitcoind;
+pub(crate) mod bitcoind;
 mod electrum;
 mod esplora;
 
@@ -15,9 +15,8 @@ use std::time::Duration;
 
 use bitcoin::{Script, Txid};
 use lightning::chain::{BestBlock, Filter};
-use lightning_block_sync::gossip::UtxoSource;
 
-use crate::chain::bitcoind::BitcoindChainSource;
+use crate::chain::bitcoind::{BitcoindChainSource, UtxoSourceClient};
 use crate::chain::electrum::ElectrumChainSource;
 use crate::chain::esplora::EsploraChainSource;
 use crate::config::{
@@ -202,7 +201,7 @@ impl ChainSource {
 		}
 	}
 
-	pub(crate) fn as_utxo_source(&self) -> Option<Arc<dyn UtxoSource>> {
+	pub(crate) fn as_utxo_source(&self) -> Option<UtxoSourceClient> {
 		match &self.kind {
 			ChainSourceKind::Bitcoind(bitcoind_chain_source) => {
 				Some(bitcoind_chain_source.as_utxo_source())

src/gossip.rs

@@ -71,7 +71,7 @@ impl GossipSource {
 				if let Some(utxo_source) = chain_source.as_utxo_source() {
 					let spawner = RuntimeSpawner::new(Arc::clone(&runtime));
 					let gossip_verifier = Arc::new(GossipVerifier::new(
-						utxo_source,
+						Arc::new(utxo_source),
 						spawner,
 						Arc::clone(gossip_sync),
 						peer_manager,

src/types.rs

@@ -23,10 +23,11 @@ use lightning::sign::InMemorySigner;
 use lightning::util::persist::{KVStore, KVStoreSync, MonitorUpdatingPersister};
 use lightning::util::ser::{Readable, Writeable, Writer};
 use lightning::util::sweep::OutputSweeper;
-use lightning_block_sync::gossip::{GossipVerifier, UtxoSource};
+use lightning_block_sync::gossip::GossipVerifier;
 use lightning_liquidity::utils::time::DefaultTimeProvider;
 use lightning_net_tokio::SocketDescriptor;
 
+use crate::chain::bitcoind::UtxoSourceClient;
 use crate::chain::ChainSource;
 use crate::config::ChannelConfig;
 use crate::data_store::DataStore;
@@ -119,7 +120,7 @@ pub(crate) type Scorer = CombinedScorer<Arc<Graph>, Arc<Logger>>;
 
 pub(crate) type Graph = gossip::NetworkGraph<Arc<Logger>>;
 
-pub(crate) type UtxoLookup = GossipVerifier<RuntimeSpawner, Arc<dyn UtxoSource>, Arc<Logger>>;
+pub(crate) type UtxoLookup = GossipVerifier<RuntimeSpawner, Arc<UtxoSourceClient>, Arc<Logger>>;
 
 pub(crate) type P2PGossipSync =
 	lightning::routing::gossip::P2PGossipSync<Arc<Graph>, Arc<UtxoLookup>, Arc<Logger>>;