Implement chain::Access trait

Author: tnull

src/access.rs

@@ -4,17 +4,18 @@ use crate::logger::{
 	log_error, log_given_level, log_info, log_internal, log_trace, log_warn, FilesystemLogger,
 	Logger,
 };
+use crate::{scid_utils, LdkLiteConfig};
 
 use lightning::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator};
 use lightning::chain::WatchedOutput;
-use lightning::chain::{Confirm, Filter};
+use lightning::chain::{Access, AccessError, Confirm, Filter};
 
 use bdk::blockchain::{Blockchain, EsploraBlockchain, GetBlockHash, GetHeight, GetTx};
 use bdk::database::BatchDatabase;
 use bdk::wallet::AddressIndex;
 use bdk::{SignOptions, SyncOptions};
 
-use bitcoin::{BlockHash, Script, Transaction, Txid};
+use bitcoin::{BlockHash, Script, Transaction, TxOut, Txid};
 
 use std::sync::{Arc, Mutex};
 
@@ -29,6 +30,7 @@ where
 	queued_outputs: Mutex<Vec<WatchedOutput>>,
 	watched_outputs: Mutex<Vec<WatchedOutput>>,
 	last_sync_height: Mutex<Option<u32>>,
+	config: Arc<LdkLiteConfig>,
 	logger: Arc<FilesystemLogger>,
 }
 
@@ -37,7 +39,8 @@ where
 	D: BatchDatabase,
 {
 	pub(crate) fn new(
-		blockchain: EsploraBlockchain, wallet: bdk::Wallet<D>, logger: Arc<FilesystemLogger>,
+		blockchain: EsploraBlockchain, wallet: bdk::Wallet<D>, config: Arc<LdkLiteConfig>,
+		logger: Arc<FilesystemLogger>,
 	) -> Self {
 		let wallet = Mutex::new(wallet);
 		let watched_transactions = Mutex::new(Vec::new());
@@ -53,6 +56,7 @@ where
 			queued_outputs,
 			watched_outputs,
 			last_sync_height,
+			config,
 			logger,
 		}
 	}
@@ -275,6 +279,44 @@ where
 	}
 }
 
+impl<D> Access for LdkLiteChainAccess<D>
+where
+	D: BatchDatabase,
+{
+	fn get_utxo(
+		&self, genesis_hash: &BlockHash, short_channel_id: u64,
+	) -> Result<TxOut, AccessError> {
+		if genesis_hash
+			!= &bitcoin::blockdata::constants::genesis_block(self.config.network)
+				.header
+				.block_hash()
+		{
+			return Err(AccessError::UnknownChain);
+		}
+
+		let block_height = scid_utils::block_from_scid(&short_channel_id);
+		let tx_index = scid_utils::tx_index_from_scid(&short_channel_id);
+		let vout = scid_utils::vout_from_scid(&short_channel_id);
+
+		let client = &*self.blockchain;
+		let block_hash = self
+			.blockchain
+			.get_block_hash(block_height.into())
+			.map_err(|_| AccessError::UnknownTx)?;
+		let txid = client
+			.get_txid_at_block_index(&block_hash, tx_index as usize)
+			.map_err(|_| AccessError::UnknownTx)?
+			.ok_or(AccessError::UnknownTx)?;
+		let tx = client
+			.get_tx(&txid)
+			.map_err(|_| AccessError::UnknownTx)?
+			.ok_or(AccessError::UnknownTx)?;
+		let tx_out = tx.output.get(vout as usize).ok_or(AccessError::UnknownTx)?;
+
+		Ok(tx_out.clone())
+	}
+}
+
 impl<D> Filter for LdkLiteChainAccess<D>
 where
 	D: BatchDatabase,

src/lib.rs

@@ -31,6 +31,7 @@ mod hex;
 mod io;
 mod logger;
 mod peer_store;
+mod scid_utils;
 
 use access::LdkLiteChainAccess;
 pub use error::LdkLiteError as Error;
@@ -227,8 +228,12 @@ impl LdkLiteBuilder {
 		let blockchain = EsploraBlockchain::new(&config.esplora_server_url, BDK_CLIENT_STOP_GAP)
 			.with_concurrency(BDK_CLIENT_CONCURRENCY);
 
-		let chain_access =
-			Arc::new(LdkLiteChainAccess::new(blockchain, bdk_wallet, Arc::clone(&logger)));
+		let chain_access = Arc::new(LdkLiteChainAccess::new(
+			blockchain,
+			bdk_wallet,
+			Arc::clone(&config),
+			Arc::clone(&logger),
+		));
 
 		// Step 3: Initialize Persist
 		let persister = Arc::new(FilesystemPersister::new(ldk_data_dir.clone()));
@@ -303,7 +308,7 @@ impl LdkLiteBuilder {
 			Arc::new(io::read_network_graph(Arc::clone(&config), Arc::clone(&logger))?);
 		let gossip_sync = Arc::new(P2PGossipSync::new(
 			Arc::clone(&network_graph),
-			None::<Arc<dyn Access + Send + Sync>>,
+			Some(Arc::clone(&chain_access)),
 			Arc::clone(&logger),
 		));
 
@@ -963,7 +968,7 @@ type PeerManager = SimpleArcPeerManager<
 	ChainMonitor,
 	LdkLiteChainAccess<bdk::sled::Tree>,
 	LdkLiteChainAccess<bdk::sled::Tree>,
-	dyn Access + Send + Sync,
+	LdkLiteChainAccess<bdk::sled::Tree>,
 	FilesystemLogger,
 >;
 
@@ -985,8 +990,11 @@ type InvoicePayer<F> = payment::InvoicePayer<
 type Router = DefaultRouter<Arc<NetworkGraph>, Arc<FilesystemLogger>>;
 type Scorer = ProbabilisticScorer<Arc<NetworkGraph>, Arc<FilesystemLogger>>;
 
-type GossipSync =
-	P2PGossipSync<Arc<NetworkGraph>, Arc<dyn Access + Send + Sync>, Arc<FilesystemLogger>>;
+type GossipSync = P2PGossipSync<
+	Arc<NetworkGraph>,
+	Arc<LdkLiteChainAccess<bdk::sled::Tree>>,
+	Arc<FilesystemLogger>,
+>;
 
 pub(crate) type NetworkGraph = gossip::NetworkGraph<Arc<FilesystemLogger>>;
 

src/scid_utils.rs

@@ -0,0 +1,33 @@
+// Copied from `rust-lightning`
+//
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+/// Maximum transaction index that can be used in a `short_channel_id`.
+/// This value is based on the 3-bytes available for tx index.
+pub const MAX_SCID_TX_INDEX: u64 = 0x00ffffff;
+
+/// Maximum vout index that can be used in a `short_channel_id`. This
+/// value is based on the 2-bytes available for the vout index.
+pub const MAX_SCID_VOUT_INDEX: u64 = 0xffff;
+
+/// Extracts the block height (most significant 3-bytes) from the `short_channel_id`
+pub fn block_from_scid(short_channel_id: &u64) -> u32 {
+	return (short_channel_id >> 40) as u32;
+}
+
+/// Extracts the tx index (bytes [2..4]) from the `short_channel_id`
+pub fn tx_index_from_scid(short_channel_id: &u64) -> u32 {
+	return ((short_channel_id >> 16) & MAX_SCID_TX_INDEX) as u32;
+}
+
+/// Extracts the vout (bytes [0..2]) from the `short_channel_id`
+pub fn vout_from_scid(short_channel_id: &u64) -> u16 {
+	return ((short_channel_id) & MAX_SCID_VOUT_INDEX) as u16;
+}