Prevent subsequent sync attempts until getTimePosition returns. (#238)

Fixes #237.

README.rst

@@ -105,6 +105,13 @@ Project resources
 Changelog
 =========
 
+(UNRELEASED)
+------------
+
+**Fixes**
+
+- Prevent excessive calls to the Mopidy server while buffering. (Fixes: `#237 <https://github.com/pimusicbox/mopidy-musicbox-webclient/issues/237>`_).
+
 v2.4.0 (2017-03-15)
 -------------------
 

mopidy_musicbox_webclient/static/js/synced_timer.js

@@ -106,8 +106,10 @@
         // check in the timeout callback than doing another function call.
         clearTimeout(this._scheduleID)
         this._isSyncScheduled = false
+        if (milliseconds >= 0) {
             this._scheduleID = setTimeout($.proxy(function () { this._isSyncScheduled = true }, this), milliseconds)
         }
+    }
 
     SyncedProgressTimer.prototype._doSync = function (position, duration) {
         var ready = !(duration === Infinity && position === 0)  // Timer has been properly initialized.
@@ -116,6 +118,8 @@
             return
         }
 
+        this._scheduleSync(-1) // Ensure that only one sync process is active at a time.
+
         var _this = this
         _this._mopidy.playback.getTimePosition().then(function (targetPosition) {
             if (_this.syncState === SyncedProgressTimer.SYNC_STATE.NOT_SYNCED) {
@@ -179,8 +183,7 @@
 
     SyncedProgressTimer.prototype.stop = function () {
         this._progressTimer.stop()
-        clearTimeout(this._scheduleID)
-        this._isSyncScheduled = false
+        this._scheduleSync(-1)
         if (this.syncState !== SyncedProgressTimer.SYNC_STATE.SYNCED && this._previousSyncPosition) {
             // Timer was busy trying to sync when it was stopped, fallback to displaying the last synced position on screen.
             this.positionNode.nodeValue = SyncedProgressTimer.format(this._previousSyncPosition)

mopidy_musicbox_webclient/static/mb.appcache

@@ -1,6 +1,6 @@
 CACHE MANIFEST
 
-# 2017-02-26:v1
+# 2017-04-14:v1
 
 NETWORK:
 *