From 737e69594ba9ef024f935b82ecbef9cda0b8fb0d Mon Sep 17 00:00:00 2001
From: Dave Collins <davec@conformal.com>
Date: Fri, 17 Jan 2014 13:11:49 -0600
Subject: [PATCH] Don't spend time on txout ntfns when no listeners.

---
 rpcwebsocket.go | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/rpcwebsocket.go b/rpcwebsocket.go
index ef536f14..0bf3550b 100644
--- a/rpcwebsocket.go
+++ b/rpcwebsocket.go
@@ -804,6 +804,11 @@ func (s *rpcServer) newBlockNotifyCheckTxIn(tx *btcutil.Tx) {
 // necessary notifications for wallets.  If a non-nil block is passed,
 // additional block information is passed with the notifications.
 func (s *rpcServer) NotifyForTxOuts(tx *btcutil.Tx, block *btcutil.Block) {
+	// Nothing to do if nobody is listening for transaction notifications.
+	if len(s.ws.txNotifications) == 0 {
+		return
+	}
+
 	for i, txout := range tx.MsgTx().TxOut {
 		_, addrs, _, err := btcscript.ExtractPkScriptAddrs(
 			txout.PkScript, s.server.btcnet)