From 4ac778d72a5d400d9d013b309e95c944e08aff5f Mon Sep 17 00:00:00 2001
From: Josh Rickmar <jrick@conformal.com>
Date: Wed, 11 Jun 2014 13:23:21 -0500
Subject: [PATCH] Do not reissue rescan requests on reconnect.

---
 infrastructure.go | 21 +++++++++++++++++++--
 notify.go         | 12 ++++++++++++
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/infrastructure.go b/infrastructure.go
index c56dc398..ee58b9d6 100644
--- a/infrastructure.go
+++ b/infrastructure.go
@@ -474,6 +474,12 @@ func (c *Client) reregisterNtfns() error {
 	return nil
 }
 
+// ignoreResends is a set of all methods for requests that are "long running"
+// are not be reissued by the client on reconnect.
+var ignoreResends = map[string]struct{}{
+	"rescan": struct{}{},
+}
+
 // resendCmds resends any commands that had not completed when the client
 // disconnected.  It is intended to be called once the client has reconnected as
 // a separate goroutine.
@@ -492,9 +498,20 @@ func (c *Client) resendCmds() {
 	// also allows the lock to be released quickly.
 	c.requestLock.Lock()
 	resendCmds := make([]*jsonRequest, 0, c.requestList.Len())
-	for e := c.requestList.Front(); e != nil; e = e.Next() {
+	var nextElem *list.Element
+	for e := c.requestList.Front(); e != nil; e = nextElem {
+		nextElem = e.Next()
+
 		req := e.Value.(*jsonRequest)
-		resendCmds = append(resendCmds, req)
+		if _, ok := ignoreResends[req.cmd.Method()]; ok {
+			// If a request is not sent on reconnect, remove it
+			// from the request structures, since no reply is
+			// expected.
+			delete(c.requestMap, req.cmd.Id().(uint64))
+			c.requestList.Remove(e)
+		} else {
+			resendCmds = append(resendCmds, req)
+		}
 	}
 	c.requestLock.Unlock()
 
diff --git a/notify.go b/notify.go
index 198abb84..28c7e686 100644
--- a/notify.go
+++ b/notify.go
@@ -897,6 +897,12 @@ func (r FutureRescanResult) Receive() error {
 //
 // See Rescan for the blocking version and more details.
 //
+// NOTE: Rescan requests are not issued on client reconnect and must be
+// performed manually (ideally with a new start height based on the last
+// rescan progress notification).  See the OnClientConnected notification
+// callback for a good callsite to reissue rescan requests on connect and
+// reconnect.
+//
 // NOTE: This is a btcd extension and requires a websocket connection.
 func (c *Client) RescanAsync(startHeight int32, addresses []btcutil.Address,
 	outpoints []*btcwire.OutPoint) FutureRescanResult {
@@ -952,6 +958,12 @@ func (c *Client) RescanAsync(startHeight int32, addresses []btcutil.Address,
 // See RescanEndHeight to also specify a block height at which to stop the
 // rescan if a bounded rescan is desired instead.
 //
+// NOTE: Rescan requests are not issued on client reconnect and must be
+// performed manually (ideally with a new start height based on the last
+// rescan progress notification).  See the OnClientConnected notification
+// callback for a good callsite to reissue rescan requests on connect and
+// reconnect.
+//
 // NOTE: This is a btcd extension and requires a websocket connection.
 func (c *Client) Rescan(startHeight int32, addresses []btcutil.Address,
 	outpoints []*btcwire.OutPoint) error {