- /// Optionally, returns any transaction dependent on the output. This is useful for Electrum
- /// clients to facilitate registering in-block descendants.
- fn register_output(&self, outpoint: &OutPoint, script_pubkey: &Script) -> Option<(usize, Transaction)>;
+ /// Optionally, when `output.block_hash` is set, should return any transaction spending the
+ /// output that is found in the corresponding block along with its index.
+ ///
+ /// This return value is useful for Electrum clients in order to supply in-block descendant
+ /// transactions which otherwise were not included. This is not necessary for other clients if
+ /// such descendant transactions were already included (e.g., when a BIP 157 client provides the
+ /// full block).
+ fn register_output(&self, output: WatchedOutput) -> Option<(usize, Transaction)>;
+}
+
+/// A transaction output watched by a [`ChannelMonitor`] for spends on-chain.
+///
+/// Used to convey to a [`Filter`] such an output with a given spending condition. Any transaction
+/// spending the output must be given to [`ChannelMonitor::block_connected`] either directly or via
+/// the return value of [`Filter::register_output`].
+///
+/// If `block_hash` is `Some`, this indicates the output was created in the corresponding block and
+/// may have been spent there. See [`Filter::register_output`] for details.
+///
+/// [`ChannelMonitor`]: channelmonitor::ChannelMonitor
+/// [`ChannelMonitor::block_connected`]: channelmonitor::ChannelMonitor::block_connected
+pub struct WatchedOutput {
+ /// First block where the transaction output may have been spent.
+ pub block_hash: Option<BlockHash>,
+
+ /// Outpoint identifying the transaction output.
+ pub outpoint: OutPoint,
+
+ /// Spending condition of the transaction output.
+ pub script_pubkey: Script,