From 4667b0ae940fd54c7fdabc6a813cfabcac63c1fc Mon Sep 17 00:00:00 2001
From: vyzo <vyzo@hackzen.org>
Date: Wed, 21 Feb 2018 16:34:25 +0200
Subject: [PATCH] fanout sources should emit gossip too

---
 gossipsub.go | 84 ++++++++++++++++++++++++++++------------------------
 1 file changed, 45 insertions(+), 39 deletions(-)

diff --git a/gossipsub.go b/gossipsub.go
index f700f3b..6835147 100644
--- a/gossipsub.go
+++ b/gossipsub.go
@@ -331,6 +331,7 @@ func (gs *GossipSubRouter) heartbeat() {
 	tograft := make(map[peer.ID][]string)
 	toprune := make(map[peer.ID][]string)
 
+	// maintain the mesh for topics we have joined
 	for topic, peers := range gs.mesh {
 
 		// check whether our peers are still in the topic
@@ -369,23 +370,36 @@ func (gs *GossipSubRouter) heartbeat() {
 			}
 		}
 
-		// schedule gossip
-		mids := gs.mcache.GetGossipIDs(topic)
-		if len(mids) == 0 {
-			continue
-		}
-
-		gpeers := gs.getPeers(topic, GossipSubD, func(peer.ID) bool { return true })
-		for _, p := range gpeers {
-			// skip mesh peers
-			_, ok := peers[p]
-			if !ok {
-				gs.pushGossip(p, &pb.ControlIHave{TopicID: &topic, MessageIDs: mids})
-			}
-		}
+		gs.emitGossip(topic, peers)
 	}
 
-	// send coalesced GRAFT/PRUNE messages
+	// maintain our fanout for topics we are publishing but we have not joined
+	for topic, peers := range gs.fanout {
+		// check whether our peers are still in the topic
+		for p := range peers {
+			_, ok := gs.p.topics[topic][p]
+			if !ok {
+				delete(peers, p)
+			}
+		}
+
+		// do we need more peers?
+		if len(peers) < GossipSubD {
+			ineed := GossipSubD - len(peers)
+			plst := gs.getPeers(topic, ineed, func(p peer.ID) bool {
+				_, ok := peers[p]
+				return !ok
+			})
+
+			for _, p := range plst {
+				peers[p] = struct{}{}
+			}
+		}
+
+		gs.emitGossip(topic, peers)
+	}
+
+	// send coalesced GRAFT/PRUNE messages (will piggyback gossip)
 	for p, topics := range tograft {
 		graft := make([]*pb.ControlGraft, 0, len(topics))
 		for _, topic := range topics {
@@ -416,34 +430,26 @@ func (gs *GossipSubRouter) heartbeat() {
 		gs.sendRPC(p, out)
 	}
 
-	// maintain our fanout for topics we are publishing but we have not joined
-	for topic, peers := range gs.fanout {
-		// check whether our peers are still in the topic
-		for p := range peers {
-			_, ok := gs.p.topics[topic][p]
-			if !ok {
-				delete(peers, p)
-			}
-		}
-
-		// do we need more peers?
-		if len(peers) < GossipSubD {
-			ineed := GossipSubD - len(peers)
-			plst := gs.getPeers(topic, ineed, func(p peer.ID) bool {
-				_, ok := peers[p]
-				return !ok
-			})
-
-			for _, p := range plst {
-				peers[p] = struct{}{}
-			}
-		}
-	}
-
 	// advance the message history window
 	gs.mcache.Shift()
 }
 
+func (gs *GossipSubRouter) emitGossip(topic string, peers map[peer.ID]struct{}) {
+	mids := gs.mcache.GetGossipIDs(topic)
+	if len(mids) == 0 {
+		return
+	}
+
+	gpeers := gs.getPeers(topic, GossipSubD, func(peer.ID) bool { return true })
+	for _, p := range gpeers {
+		// skip mesh peers
+		_, ok := peers[p]
+		if !ok {
+			gs.pushGossip(p, &pb.ControlIHave{TopicID: &topic, MessageIDs: mids})
+		}
+	}
+}
+
 func (gs *GossipSubRouter) flush() {
 	// send gossip first, which will also piggyback control
 	for p, ihave := range gs.gossip {