Merge lp:~ahayzen/music-app/remix-fix-1386628-slow-trackclicked into lp:music-app/remix

[Andrew Hayzen]

* Optimise the addQueueList transaction

* Optimise the addQueueList transaction

This reduces the overall time from the track being clicking to playing from ~2.4s -> 1.1s on my N4. The remaining time is split up over the following:
* model.clear() ~75ms
* addQueueFromModel() ~325ms (110ms going to addQueueList [was 1000ms+ before] the rest append to trackQueue)
* MediaPlayer.play() ~450ms
* pushNowPlaying() ~300ms

I attempted to use a worker script to speed up the appending to trackQueue, but that actually resulted in slow down. The next areas of investigation should probably be why MediaPlayer.play() takes 450ms (we should compare on desktop as well as device [note MediaPlayer takes 175ms to create as well]) and investigate incubateObject for pushNowPlaying(). Maybe the page could be incubating while we are pushing to the model?

TL;DR; this MP reduces the trackClicked time by ~2.4->1.1 in a certain scenario but there are still areas for improvement.

[Ubuntu Phone Apps Jenkins Bot (ubuntu-phone-apps-jenkins-bot)]

PASSED: Continuous integration, rev:714
http://91.189.93.70:8080/job/music-app-remix-ci/208/
Executed test runs:
    SUCCESS: http://91.189.93.70:8080/job/generic-mediumtests-utopic-python3/1357
        deb: http://91.189.93.70:8080/job/generic-mediumtests-utopic-python3/1357/artifact/work/output/*zip*/output.zip
    SUCCESS: http://91.189.93.70:8080/job/music-app-remix-utopic-amd64-ci/208

Click here to trigger a rebuild:
http://91.189.93.70:8080/job/music-app-remix-ci/208/rebuild

review: Approve (continuous-integration)

[Victor Thompson (vthompson)]

Could we not call the array "model" inside the addQueueList() function... it's misleading.

review: Needs Fixing

[lp:~ahayzen/music-app/remix-fix-1386628-slow-trackclicked]

715. By Andrew Hayzen on 2014-10-29

* Rename variable from model to items

[Victor Thompson (vthompson)]

LGTM!

review: Approve

=== modified file 'meta-database.js'
--- meta-database.js	2014-10-28 03:32:01 +0000
+++ meta-database.js	2014-10-29 01:20:43 +0000
@@ -56,19 +56,12 @@
     );
 }
 
-function addQueueList(model) {
+function addQueueList(items) {
     var db = getDatabase();
-    var res="";
 
     db.transaction(function(tx) {
-
-        for (var i = 0; i < model.count; i++) {
-            var rs = tx.executeSql('INSERT OR REPLACE INTO queue (ind, filename) VALUES (?,?);', [i, model.get(i).filename]);
-            if (rs.rowsAffected > 0) {
-                res = "OK";
-            } else {
-                res = "Error";
-            }
+        for (var i = 0; i < items.length; i++) {
+            tx.executeSql('INSERT OR REPLACE INTO queue (ind, filename) VALUES (?,?);', [i, items[i].filename]);
         }
     }
     );

=== modified file 'music-app.qml'
--- music-app.qml	2014-10-28 03:39:30 +0000
+++ music-app.qml	2014-10-29 01:20:43 +0000
@@ -608,12 +608,16 @@
             model = model.linkLibraryListModel;
         }
 
+        var items = []
+
         for (var i=0; i < model.rowCount; i++) {
-            trackQueue.model.append(model.get(i, model.RoleModelData));
+            items.push(model.get(i, model.RoleModelData))
+
+            trackQueue.model.append(items[i]);
         }
 
         // Add model to queue storage
-        Library.addQueueList(trackQueue.model);
+        Library.addQueueList(items);
     }
 
     // Converts an duration in ms to a formated string ("minutes:seconds")