From 7f766d89c32feba745c3d3000c64e94be5431226 Mon Sep 17 00:00:00 2001
From: Luke Barnard <lukeb@openmarket.com>
Date: Wed, 10 May 2017 14:42:06 +0100
Subject: [PATCH] Rename variables, more comments

---
 src/components/structures/TimelinePanel.js | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/components/structures/TimelinePanel.js b/src/components/structures/TimelinePanel.js
index 973c619904..874c6b1ac0 100644
--- a/src/components/structures/TimelinePanel.js
+++ b/src/components/structures/TimelinePanel.js
@@ -507,7 +507,7 @@ var TimelinePanel = React.createClass({
         // if no client or client is guest don't send RR or RM
         if (!cli || cli.isGuest()) return;
 
-        let shouldSendRR = true;
+        let shouldSendReadReceipt = true;
 
         var currentReadUpToEventId = this._getCurrentReadReceipt(true);
         var currentReadUpToEventIndex = this._indexForEventId(currentReadUpToEventId);
@@ -526,26 +526,30 @@ var TimelinePanel = React.createClass({
         //
         if (currentReadUpToEventId && currentReadUpToEventIndex === null &&
                 this._timelineWindow.canPaginate(EventTimeline.FORWARDS)) {
-            shouldSendRR = false;
+            shouldSendReadReceipt = false;
         }
 
         var lastReadEventIndex = this._getLastDisplayedEventIndex({
             ignoreOwn: true
         });
         if (lastReadEventIndex === null) {
-            shouldSendRR = false;
+            shouldSendReadReceipt = false;
         }
 
         var lastReadEvent = this.state.events[lastReadEventIndex];
-        shouldSendRR = shouldSendRR &&
-            (lastReadEventIndex > currentReadUpToEventIndex &&
-            this.last_rr_sent_event_id != lastReadEvent.getId());
+        shouldSendReadReceipt = shouldSendReadReceipt &&
+            // Only send a RR if the last read Event is ahead in the timeline relative to
+            // the current RR event.
+            lastReadEventIndex > currentReadUpToEventIndex &&
+            // Only send a RR if the last RR set != the one we would send
+            this.last_rr_sent_event_id != lastReadEvent.getId();
 
-        const shouldSendRM = this.last_rm_sent_event_id != this.state.readMarkerEventId;
+        // Only send a RM if the last RM sent != the one we would send
+        const shouldSendReadMarker = this.last_rm_sent_event_id != this.state.readMarkerEventId;
 
         // we also remember the last read receipt we sent to avoid spamming the
         // same one at the server repeatedly
-        if (shouldSendRR || shouldSendRM) {
+        if (shouldSendReadReceipt || shouldSendReadMarker) {
             this.last_rr_sent_event_id = lastReadEvent.getId();
             this.last_rm_sent_event_id = this.state.readMarkerEventId;