Replace WatchEvent usage with get_outputs_to_watch

Outputs to watch are tracked by ChannelMonitor as of
73dce20. Instead of determining new
outputs to watch independently using ChainWatchedUtil, do so by
comparing against outputs already tracked. Thus, ChainWatchedUtil and
WatchEvent are no longer needed.

Author: jkczyz

lightning/src/chain/chaininterface.rs

@@ -14,10 +14,6 @@
 //! disconnections, transaction broadcasting, and feerate information requests.
 
 use bitcoin::blockdata::transaction::Transaction;
-use bitcoin::blockdata::script::Script;
-use bitcoin::hash_types::Txid;
-
-use std::collections::HashSet;
 
 /// An interface to send a transaction to the Bitcoin network.
 pub trait BroadcasterInterface: Sync + Send {
@@ -55,91 +51,3 @@ pub trait FeeEstimator: Sync + Send {
 
 /// Minimum relay fee as required by bitcoin network mempool policy.
 pub const MIN_RELAY_FEE_SAT_PER_1000_WEIGHT: u64 = 4000;
-
-/// Utility for tracking registered txn/outpoints and checking for matches
-#[cfg_attr(test, derive(PartialEq))]
-pub struct ChainWatchedUtil {
-	watch_all: bool,
-
-	// We are more conservative in matching during testing to ensure everything matches *exactly*,
-	// even though during normal runtime we take more optimized match approaches...
-	#[cfg(test)]
-	watched_txn: HashSet<(Txid, Script)>,
-	#[cfg(not(test))]
-	watched_txn: HashSet<Script>,
-
-	watched_outpoints: HashSet<(Txid, u32)>,
-}
-
-impl ChainWatchedUtil {
-	/// Constructs an empty (watches nothing) ChainWatchedUtil
-	pub fn new() -> Self {
-		Self {
-			watch_all: false,
-			watched_txn: HashSet::new(),
-			watched_outpoints: HashSet::new(),
-		}
-	}
-
-	/// Registers a tx for monitoring, returning true if it was a new tx and false if we'd already
-	/// been watching for it.
-	pub fn register_tx(&mut self, txid: &Txid, script_pub_key: &Script) -> bool {
-		if self.watch_all { return false; }
-		#[cfg(test)]
-		{
-			self.watched_txn.insert((txid.clone(), script_pub_key.clone()))
-		}
-		#[cfg(not(test))]
-		{
-			let _tx_unused = txid; // It's used in cfg(test), though
-			self.watched_txn.insert(script_pub_key.clone())
-		}
-	}
-
-	/// Registers an outpoint for monitoring, returning true if it was a new outpoint and false if
-	/// we'd already been watching for it
-	pub fn register_outpoint(&mut self, outpoint: (Txid, u32), _script_pub_key: &Script) -> bool {
-		if self.watch_all { return false; }
-		self.watched_outpoints.insert(outpoint)
-	}
-
-	/// Sets us to match all transactions, returning true if this is a new setting and false if
-	/// we'd already been set to match everything.
-	pub fn watch_all(&mut self) -> bool {
-		if self.watch_all { return false; }
-		self.watch_all = true;
-		true
-	}
-
-	/// Checks if a given transaction matches the current filter.
-	pub fn does_match_tx(&self, tx: &Transaction) -> bool {
-		if self.watch_all {
-			return true;
-		}
-		for out in tx.output.iter() {
-			#[cfg(test)]
-			for &(ref txid, ref script) in self.watched_txn.iter() {
-				if *script == out.script_pubkey {
-					if tx.txid() == *txid {
-						return true;
-					}
-				}
-			}
-			#[cfg(not(test))]
-			for script in self.watched_txn.iter() {
-				if *script == out.script_pubkey {
-					return true;
-				}
-			}
-		}
-		for input in tx.input.iter() {
-			for outpoint in self.watched_outpoints.iter() {
-				let &(outpoint_hash, outpoint_index) = outpoint;
-				if outpoint_hash == input.previous_output.txid && outpoint_index == input.previous_output.vout {
-					return true;
-				}
-			}
-		}
-		false
-	}
-}

lightning/src/chain/mod.rs

@@ -73,8 +73,7 @@ pub trait Watch: Send + Sync {
 	///
 	/// Implementations are responsible for watching the chain for the funding transaction along
 	/// with any spends of outputs returned by [`get_outputs_to_watch`]. In practice, this means
-	/// calling [`block_connected`] and [`block_disconnected`] on the monitor and including all such
-	/// transactions that meet this criteria.
+	/// calling [`block_connected`] and [`block_disconnected`] on the monitor.
 	///
 	/// [`get_outputs_to_watch`]: ../ln/channelmonitor/struct.ChannelMonitor.html#method.get_outputs_to_watch
 	/// [`block_connected`]: ../ln/channelmonitor/struct.ChannelMonitor.html#method.block_connected
@@ -119,9 +118,9 @@ pub trait Watch: Send + Sync {
 pub trait Filter: Send + Sync {
 	/// Registers interest in a transaction with `txid` and having an output with `script_pubkey` as
 	/// a spending condition.
-	fn register_tx(&self, txid: Txid, script_pubkey: Script);
+	fn register_tx(&self, txid: &Txid, script_pubkey: &Script);
 
 	/// Registers interest in spends of a transaction output identified by `outpoint` having
 	/// `script_pubkey` as the spending condition.
-	fn register_output(&self, outpoint: OutPoint, script_pubkey: Script);
+	fn register_output(&self, outpoint: &OutPoint, script_pubkey: &Script);
 }