From 3d5d9be02a494dcb1e7081571c7d920b3342aa0b Mon Sep 17 00:00:00 2001
From: Milos Gajdos <milosgajdos83@gmail.com>
Date: Fri, 18 Oct 2019 11:23:28 +0100
Subject: [PATCH] Avoid recursive calls to RLock()

Topology calls itsel recursively invoking RLock. This, according to go
documentation is wrong. This commit moves the body of Topology function
to a non-thread safe unexported function to keep locsk at check!
---
 network/node.go | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/network/node.go b/network/node.go
index 194dd6d2..e8632ccc 100644
--- a/network/node.go
+++ b/network/node.go
@@ -237,12 +237,9 @@ func (n *node) PruneStalePeerNodes(pruneTime time.Duration) map[string]*node {
 	return pruned
 }
 
-// Topology returns a copy of the node topology down to given depth
-// NOTE: the returned node is a node graph - not a single node
-func (n *node) Topology(depth uint) *node {
-	n.RLock()
-	defer n.RUnlock()
-
+// getTopology traverses node graph and builds node topology
+// NOTE: this function is not thread safe
+func (n *node) getTopology(depth uint) *node {
 	// make a copy of yourself
 	node := &node{
 		id:       n.id,
@@ -262,7 +259,7 @@ func (n *node) Topology(depth uint) *node {
 
 	// iterate through our peers and update the node peers
 	for _, peer := range n.peers {
-		nodePeer := peer.Topology(depth)
+		nodePeer := peer.getTopology(depth)
 		if _, ok := node.peers[nodePeer.id]; !ok {
 			node.peers[nodePeer.id] = nodePeer
 		}
@@ -271,6 +268,15 @@ func (n *node) Topology(depth uint) *node {
 	return node
 }
 
+// Topology returns a copy of the node topology down to given depth
+// NOTE: the returned node is a node graph - not a single node
+func (n *node) Topology(depth uint) *node {
+	n.RLock()
+	defer n.RUnlock()
+
+	return n.getTopology(depth)
+}
+
 // Peers returns node peers up to MaxDepth
 func (n *node) Peers() []Node {
 	n.RLock()
@@ -278,7 +284,7 @@ func (n *node) Peers() []Node {
 
 	var peers []Node
 	for _, nodePeer := range n.peers {
-		peer := nodePeer.Topology(MaxDepth)
+		peer := nodePeer.getTopology(MaxDepth)
 		peers = append(peers, peer)
 	}