refactor: extract nameserver GossipData.copy

and remove a self-evident comment

nameserver/entry.go

@@ -247,11 +247,7 @@ type GossipData struct {
 
 func (g *GossipData) Merge(o mesh.GossipData) mesh.GossipData {
 	other := o.(*GossipData)
-	gossip := &GossipData{
-		Entries:   make(Entries, len(g.Entries)),
-		Timestamp: g.Timestamp,
-	}
-	copy(gossip.Entries, g.Entries)
+	gossip := g.copy()
 	gossip.Entries.merge(other.Entries)
 	if gossip.Timestamp < other.Timestamp {
 		gossip.Timestamp = other.Timestamp
@@ -270,9 +266,7 @@ func (g *GossipData) Decode(msg []byte) error {
 }
 
 func (g *GossipData) Encode() [][]byte {
-	// Make a copy so we can sort: all outgoing data is sent in case-sensitive order
-	g2 := GossipData{Timestamp: g.Timestamp, Entries: make(Entries, len(g.Entries))}
-	copy(g2.Entries, g.Entries)
+	g2 := g.copy()
 	sort.Sort(CaseSensitive(g2.Entries))
 	buf := &bytes.Buffer{}
 	if err := gob.NewEncoder(buf).Encode(g2); err != nil {
@@ -280,3 +274,9 @@ func (g *GossipData) Encode() [][]byte {
 	}
 	return [][]byte{buf.Bytes()}
 }
+
+func (g *GossipData) copy() *GossipData {
+	g2 := &GossipData{Timestamp: g.Timestamp, Entries: make(Entries, len(g.Entries))}
+	copy(g2.Entries, g.Entries)
+	return g2
+}