Return true or false from AddData().

Returns false and aborts the data addition if there is no change in the delta.
Use this to shortcut applyUpdateFromNewState() which prevents sending out
notifications for empty deltas.

cmd/stayrtr/stayrtr.go

@@ -445,10 +445,13 @@ func (s *state) applyUpdateFromNewState(vrps []rtr.VRP, brks []rtr.BgpsecKey, va
 	for _, v := range vaps {
 		SDs = append(SDs, v.Copy())
 	}
-	s.server.AddData(SDs)
+	if (s.server.AddData(SDs) == false) {
+		log.Info("No difference to current cache")
+		return nil
+	}
 
 	serial, _ := s.server.GetCurrentSerial(sessid)
-	log.Infof("Updated added, new serial %v", serial)
+	log.Infof("Update added, new serial %v", serial)
 	if s.sendNotifs {
 		log.Debugf("Sending notifications to clients")
 		s.server.NotifyClientsLatest()

lib/server.go

@@ -361,7 +361,7 @@ func (s *Server) CountSDs() int {
 	return len(s.sdCurrent)
 }
 
-func (s *Server) AddData(new []SendableData) {
+func (s *Server) AddData(new []SendableData) bool {
 	s.sdlock.RLock()
 
 	added, removed, _ := ComputeDiff(new, s.sdCurrent, false)
@@ -373,7 +373,12 @@ func (s *Server) AddData(new []SendableData) {
 	curDiff := append(added, removed...)
 	s.sdlock.RUnlock()
 
-	s.AddSDsDiff(curDiff)
+	if (len(curDiff) == 0) {
+		return false
+	} else {
+		s.AddSDsDiff(curDiff)
+		return true
+	}
 }
 
 func (s *Server) addSerial(serial uint32) []uint32 {