From 01a28ef3b070aa0c240c6606981bd25ca9691e1e Mon Sep 17 00:00:00 2001
From: Sarah Jamie Lewis <sarah@openprivacy.ca>
Date: Mon, 3 Dec 2018 11:12:34 -0800
Subject: [PATCH] Message Sorting

---
 model/group.go   | 10 ++++------
 model/message.go | 13 +++++++++++++
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/model/group.go b/model/group.go
index bd84bb3..d15dd6a 100644
--- a/model/group.go
+++ b/model/group.go
@@ -122,13 +122,11 @@ func (g *Group) AddMessage(message *protocol.DecryptedGroupMessage, sig []byte)
 	return timelineMessage
 }
 
-// GetTimeline provides a safe copy of the timeline-=
-func (g *Group) GetTimeline() (t []Message) {
+// GetTimeline provides a safe copy of the timeline
+func (g *Group) GetTimeline() (timeline []Message) {
 	g.lock.Lock()
-	t = g.Timeline.GetMessages()
-	g.lock.Unlock()
-	return
-
+	defer g.lock.Unlock()
+	return g.Timeline.GetMessages()
 }
 
 //EncryptMessage takes a message and encrypts the message under the group key.
diff --git a/model/message.go b/model/message.go
index ded861d..065fc71 100644
--- a/model/message.go
+++ b/model/message.go
@@ -58,6 +58,11 @@ func (t *Timeline) Swap(i, j int) {
 // Less checks 2 messages (i and j) in the timeline and returns true if i occurred before j, else false
 func (t *Timeline) Less(i, j int) bool {
 
+	if t.Messages[i].Timestamp.Before(t.Messages[j].Timestamp) {
+		return true
+	}
+
+	// Short circuit false if j is before i, signature checks will give a wrong order in this case.
 	if t.Messages[j].Timestamp.Before(t.Messages[i].Timestamp) {
 		return false
 	}
@@ -73,6 +78,14 @@ func (t *Timeline) Less(i, j int) bool {
 	return false
 }
 
+// Sort sorts the timeline in a canonical order.
+// TODO: There is almost definitely a more efficient way of doing things that involve not calling this method on every timeline load.
+func (t *Timeline) Sort() {
+	t.lock.Lock()
+	defer t.lock.Unlock()
+	sort.Sort(t)
+}
+
 // Insert inserts a message into the timeline in a thread safe way.
 func (t *Timeline) Insert(mi *Message) bool {
 	t.lock.Lock()