From f213901e29721283639817350d8375d7c8e92658 Mon Sep 17 00:00:00 2001
From: Kegan Dougal <kegan@matrix.org>
Date: Fri, 22 Jan 2016 11:11:56 +0000
Subject: [PATCH 1/2] Return early when calculating one-to-one room avatars

Object.keys() is O(n) and is wasted because we only care if the keys are 1 or 2.
Use `for .. in` instead and return early if there are >2 keys.

Profiling indicates this cuts wasted time from ~74ms to ~32ms for me (who has
a large number of rooms with large numbers of people in them).
---
 src/components/views/avatars/RoomAvatar.js | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/src/components/views/avatars/RoomAvatar.js b/src/components/views/avatars/RoomAvatar.js
index 72ca5f7f21..eed4070fd8 100644
--- a/src/components/views/avatars/RoomAvatar.js
+++ b/src/components/views/avatars/RoomAvatar.js
@@ -67,14 +67,24 @@ module.exports = React.createClass({
     },
 
     getOneToOneAvatar: function(props) {
-        var userIds = Object.keys(props.room.currentState.members);
+        var mlist = props.room.currentState.members;
+        var userIds = [];
+        // for .. in optimisation to return early if there are >2 keys
+        for (var uid in mlist) {
+            if (mlist.hasOwnProperty(uid)) {
+                userIds.push(uid);
+            }
+            if (userIds.length > 2) {
+                return null;
+            }
+        }
 
         if (userIds.length == 2) {
             var theOtherGuy = null;
-            if (props.room.currentState.members[userIds[0]].userId == MatrixClientPeg.get().credentials.userId) {
-                theOtherGuy = props.room.currentState.members[userIds[1]];
+            if (mlist[userIds[0]].userId == MatrixClientPeg.get().credentials.userId) {
+                theOtherGuy = mlist[userIds[1]];
             } else {
-                theOtherGuy = props.room.currentState.members[userIds[0]];
+                theOtherGuy = mlist[userIds[0]];
             }
             return theOtherGuy.getAvatarUrl(
                 MatrixClientPeg.get().getHomeserverUrl(),
@@ -82,7 +92,7 @@ module.exports = React.createClass({
                 false
             );
         } else if (userIds.length == 1) {
-            return props.room.currentState.members[userIds[0]].getAvatarUrl(
+            return mlist[userIds[0]].getAvatarUrl(
                 MatrixClientPeg.get().getHomeserverUrl(),
                 props.width, props.height, props.resizeMethod,
                     false

From 7ef1ba0b44e0e2c73e4e30af99c27932fd05ebe1 Mon Sep 17 00:00:00 2001
From: Kegan Dougal <kegan@matrix.org>
Date: Fri, 22 Jan 2016 11:48:26 +0000
Subject: [PATCH 2/2] Unbreak RoomHeader

---
 src/components/views/rooms/RoomHeader.js | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/src/components/views/rooms/RoomHeader.js b/src/components/views/rooms/RoomHeader.js
index 6fab2a9989..0b52281507 100644
--- a/src/components/views/rooms/RoomHeader.js
+++ b/src/components/views/rooms/RoomHeader.js
@@ -20,6 +20,7 @@ var React = require('react');
 var sdk = require('../../../index');
 var dis = require("../../../dispatcher");
 var MatrixClientPeg = require('../../../MatrixClientPeg');
+var Modal = require("../../../Modal");
 
 var linkify = require('linkifyjs');
 var linkifyElement = require('linkifyjs/element');
@@ -103,17 +104,14 @@ module.exports = React.createClass({
             console.error("No ChangeAvatar found to upload image to!");
             return;
         }
-        changeAvatar.onFileSelected(ev).done(function() {
-            // dunno if the avatar changed, re-check it.
-            self._refreshFromServer();
-        }, function(err) {
+        changeAvatar.onFileSelected(ev).catch(function(err) {
             var errMsg = (typeof err === "string") ? err : (err.error || "");
             var ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
             Modal.createDialog(ErrorDialog, {
                 title: "Error",
                 description: "Failed to set avatar. " + errMsg
             });
-        });
+        }).done();
     },    
 
     getRoomName: function() {