Bug fix: Plugin Sync

1. Failed to create more than one realtime document.
   Pass assignIdCallback and failedCallback as function parameter for FileSearcher instead of saving it.

2. If a client with empty data use Sync plugin first, other clients will lose their data once connected with Realtime API.
   Assign '' to lastUpdateUUID on model initialization if the client do not have data.

3. Realtime API sometimes return 'CLIENT_ERROR' instead of 'NOT_FOUND' if a file is not found
   Change handling of 'CLIENT_ERROR' to the same as 'NOT_FOUND'

plugins/sync.user.js

@@ -135,7 +135,8 @@ window.plugin.sync.RegisteredMap.prototype.updateMap = function(keyArray) {
 }
 
 window.plugin.sync.RegisteredMap.prototype.isUpdatedByOthers = function() {
-  return this.lastUpdateUUID.toString() !== this.uuid;
+  var remoteUUID = this.lastUpdateUUID.toString();
+  return (remoteUUID !== '') && (remoteUUID !== this.uuid);
 }
 
 window.plugin.sync.RegisteredMap.prototype.getFileName = function() {
@@ -159,10 +160,8 @@ window.plugin.sync.RegisteredMap.prototype.initFile = function(callback) {
   }
 
   this.fileSearcher = new plugin.sync.FileSearcher({'fileName': this.getFileName(),
-                                                    'description': 'IITC plugin data for ' + this.getFileName(),
+                                                    'description': 'IITC plugin data for ' + this.getFileName()});
-                                                    'assignIdCallback': assignIdCallback,
+  this.fileSearcher.initialize(this.forceFileSearch, assignIdCallback, failedCallback);
-                                                    'failedCallback': failedCallback});
-  this.fileSearcher.initialize(this.forceFileSearch);
 }
 
 window.plugin.sync.RegisteredMap.prototype.updateListener = function(e) {
@@ -191,14 +190,18 @@ window.plugin.sync.RegisteredMap.prototype.loadRealtimeDocument = function(callb
   // this function called when the document is created first time
   // and the CollaborativeMap is populated with data in plugin field
   initializeModel = function(model) {
+    var empty = true;
     var map = model.createMap();
     var lastUpdateUUID = model.createString();
 
     // Init the map values if this map is first created
     $.each(window.plugin[_this.pluginName][_this.fieldName], function(key, val) {
       map.set(key, val);
+      empty = false;
     });
-    lastUpdateUUID.setText(_this.uuid);
+
+    // Only set the update client if the map is not empty, avoid clearing data of other clients
+    lastUpdateUUID.setText(empty ? '' : _this.uuid);
 
     model.getRoot().set('map', map);
     model.getRoot().set('last-udpate-uuid', lastUpdateUUID);
@@ -211,8 +214,8 @@ window.plugin.sync.RegisteredMap.prototype.loadRealtimeDocument = function(callb
   onFileLoaded = function(doc) {
     _this.doc = doc;
     _this.model = doc.getModel();
-    _this.map = doc.getModel().getRoot().get("map");
+    _this.map = doc.getModel().getRoot().get('map');
-    _this.lastUpdateUUID = doc.getModel().getRoot().get("last-udpate-uuid");
+    _this.lastUpdateUUID = doc.getModel().getRoot().get('last-udpate-uuid');
     _this.map.addEventListener(gapi.drive.realtime.EventType.VALUE_CHANGED, _this.updateListener);
 
     // Replace local value if data is changed by others
@@ -240,6 +243,10 @@ window.plugin.sync.RegisteredMap.prototype.loadRealtimeDocument = function(callb
       _this.authorizer.authorize();
     } else if(e.type === gapi.drive.realtime.ErrorType.NOT_FOUND) {
       _this.forceFileSearch = true;
+    } else if(e.type === gapi.drive.realtime.ErrorType.CLIENT_ERROR) {
+      // Workaround: if Realtime API open a second docuemnt and the file do not exist, 
+      // it will rasie 'CLIENT_ERROR' instead of 'NOT_FOUND'. So we do a force file search here.
+      _this.forceFileSearch = true;
     } else {
       alert('Plugin Sync error: ' + e.type + ', ' + e.message);
     }
@@ -367,8 +374,6 @@ window.plugin.sync.FileSearcher = function(options) {
   this.fileName = options['fileName'];
   this.description = options['description'];
   this.isFolder = options['isFolder'];
-  this.assignIdCallback = options['assignIdCallback'];
-  this.failedCallback = options['failedCallback'];
 
   this.force = false;
   this.parent = null;
@@ -386,27 +391,27 @@ window.plugin.sync.FileSearcher.prototype.MIMETYPE_FOLDER = 'application/vnd.goo
 window.plugin.sync.FileSearcher.prototype.parentName = 'IITC-SYNC-DATA-V2';
 window.plugin.sync.FileSearcher.prototype.parentDescription = 'Store IITC sync data';
 
-window.plugin.sync.FileSearcher.prototype.initialize = function(force) {
+window.plugin.sync.FileSearcher.prototype.initialize = function(force, assignIdCallback, failedCallback) {
   this.force = force;
   // throw error if too many retry
   if(this.retryCount >= this.RETRY_LIMIT) {
     plugin.sync.logger.log('Too many file operation: ' + this.fileName);
-    this.failedCallback();
+    failedCallback();
     return;
   }
   if(this.force) this.retryCount++;
 
   if(this.isFolder) {
-    this.initFile();
+    this.initFile(assignIdCallback, failedCallback);
   } else {
-    this.initParent();
+    this.initParent(assignIdCallback, failedCallback);
   }
 }
 
-window.plugin.sync.FileSearcher.prototype.initFile = function() {
+window.plugin.sync.FileSearcher.prototype.initFile = function(assignIdCallback, failedCallback) {
   // If not force search and have cached fileId, return the fileId
   if(!this.force && this.fileId) {
-    this.assignIdCallback(this.fileId);
+    assignIdCallback(this.fileId);
     return;
   }
 
@@ -416,14 +421,14 @@ window.plugin.sync.FileSearcher.prototype.initFile = function() {
   handleFileId = function(id) {
     _this.fileId = id;
     _this.saveFileId();
-    _this.assignIdCallback(id);
+    assignIdCallback(id);
   };
 
   handleFailed = function(resp) {
     _this.fileId = null;
     _this.saveFileId();
     plugin.sync.logger.log('File operation failed: ' + (resp.error || 'unknown error'));
-    _this.failedCallback(resp);
+    failedCallback(resp);
   }
 
   createCallback = function(resp) {
@@ -447,27 +452,25 @@ window.plugin.sync.FileSearcher.prototype.initFile = function() {
   this.searchFileOrFolder(searchCallback);
 }
 
-window.plugin.sync.FileSearcher.prototype.initParent = function() {
+window.plugin.sync.FileSearcher.prototype.initParent = function(assignIdCallback, failedCallback) {
-  var assignIdCallback, failedCallback, _this;
+  var parentAssignIdCallback, parentFailedCallback, _this;
   _this = this;
 
-  assignIdCallback = function(id) {
+  parentAssignIdCallback = function(id) {
-    _this.initFile();
+    _this.initFile(assignIdCallback, failedCallback);
   }
 
-  failedCallback = function(resp) {
+  parentFailedCallback = function(resp) {
     _this.fileId = null;
     _this.saveFileId();
     plugin.sync.logger.log('File operation failed: ' + (resp.error || 'unknown error'));
-    _this.failedCallback(resp);
+    failedCallback(resp);
   }
 
   this.parent = new plugin.sync.FileSearcher({'fileName': this.parentName,
                                   'description': this.parentDescription,
-                                  'isFolder': true,
+                                  'isFolder': true});
-                                  'assignIdCallback': assignIdCallback,
+  this.parent.initialize(this.force, parentAssignIdCallback, parentFailedCallback);
-                                  'failedCallback': failedCallback});
-  this.parent.initialize(this.force);
 }
 
 window.plugin.sync.FileSearcher.prototype.createFileOrFolder = function(callback) {
@@ -629,12 +632,12 @@ window.plugin.sync.generateUUID = function() {
     window.crypto.getRandomValues(buf);
     var S4 = function(num) {
       var ret = num.toString(16);
-      return "000".substring(0, 4-ret.length) + ret;
+      return '000'.substring(0, 4-ret.length) + ret;
     };
     var yxxx = function(num) {
       return num&0x3fff|0x8000;
     }
-    return (S4(buf[0])+S4(buf[1])+"-"+S4(buf[2])+"-4"+S4(buf[3]).substring(1)+"-"+S4(yxxx(buf[4]))+"-"+S4(buf[5])+S4(buf[6])+S4(buf[7]));
+    return (S4(buf[0])+S4(buf[1])+'-'+S4(buf[2])+'-4'+S4(buf[3]).substring(1)+'-'+S4(yxxx(buf[4]))+'-'+S4(buf[5])+S4(buf[6])+S4(buf[7]));
   } else {
     var d = new Date().getTime();
     var uuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {