lightningd: actually unwatch txs when onchaind says we should.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

lightningd/peer_control.c

@@ -1193,7 +1193,20 @@ static void handle_onchain_broadcast_tx(struct peer *peer, const u8 *msg)
 
 static void handle_onchain_unwatch_tx(struct peer *peer, const u8 *msg)
 {
-	/* FIXME: unwatch tx and children here. */
+	struct bitcoin_txid txid;
+	struct txwatch *txw;
+
+	if (!fromwire_onchain_unwatch_tx(msg, NULL, &txid)) {
+		peer_internal_error(peer, "Invalid onchain_unwatch_tx");
+		return;
+	}
+
+	/* Frees the txo watches, too: see watch_tx_and_outputs() */
+	txw = find_txwatch(peer->ld->topology, &txid, peer);
+	if (!txw)
+		log_unusual(peer->log, "Can't unwatch txid %s",
+			    type_to_string(ltmp, struct bitcoin_txid, &txid));
+	tal_free(txw);
 }
 
 static void handle_extracted_preimage(struct peer *peer, const u8 *msg)

lightningd/watch.c

@@ -112,6 +112,24 @@ struct txwatch *watch_txid_(const tal_t *ctx,
 	return w;
 }
 
+struct txwatch *find_txwatch(struct chain_topology *topo,
+			     const struct bitcoin_txid *txid,
+			     const struct peer *peer)
+{
+	struct txwatch_hash_iter i;
+	struct txwatch *w;
+
+	/* We could have more than one peer watching same txid, though we
+	 * don't for onchaind. */
+	for (w = txwatch_hash_getfirst(&topo->txwatches, txid, &i);
+	     w;
+	     w = txwatch_hash_getnext(&topo->txwatches, txid, &i)) {
+		if (w->peer == peer)
+			break;
+	}
+	return w;
+}
+
 bool watching_txid(const struct chain_topology *topo,
 		   const struct bitcoin_txid *txid)
 {

lightningd/watch.h

@@ -134,6 +134,10 @@ struct txowatch *watch_txo_(const tal_t *ctx,
 				       const struct block *block),	\
 		  (cbdata))
 
+struct txwatch *find_txwatch(struct chain_topology *topo,
+			     const struct bitcoin_txid *txid,
+			     const struct peer *peer);
+
 void txwatch_fire(struct chain_topology *topo,
 		  const struct bitcoin_tx *tx,
 		  unsigned int depth);