Refoctoring FileSelection and FileSelectionHandler.

ui/file_manager/file_manager/foreground/js/file_selection.js

Index: ui/file_manager/file_manager/foreground/js/file_selection.js
diff --git a/ui/file_manager/file_manager/foreground/js/file_selection.js b/ui/file_manager/file_manager/foreground/js/file_selection.js
index f1655ef4230cd4607ad552301eb3d15ec36e2fd3..e582294f7c523fbdc4506992ef9437a8f4313b82 100644
--- a/ui/file_manager/file_manager/foreground/js/file_selection.js
+++ b/ui/file_manager/file_manager/foreground/js/file_selection.js
@@ -5,26 +5,99 @@
 /**
  * The current selection object.
  *
- * @param {FileManager} fileManager FileManager instance.
- * @param {Array.<number>} indexes Selected indexes.
+ * @param {!FileManager} fileManager FileManager instance.
+ * @param {!Array.<number>} indexes Selected indexes.
  * @constructor
+ * @struct
  */
 function FileSelection(fileManager, indexes) {
+  /**
+   * @type {!FileManager}
+   * @private
+   * @const
+   */
   this.fileManager_ = fileManager;
+
+  /**
+   * @type {number}
+   * @private
+   */
   this.computeBytesSequence_ = 0;
+
+  /**
+   * @type {!Array.<number>}
+   * @const
+   */
   this.indexes = indexes;
+
+  /**
+   * @type {!Array.<!Entry>}
+   * @const
+   */
   this.entries = [];
+
+  /**
+   * @type {number}
+   */
   this.totalCount = 0;
+
+  /**
+   * @type {number}
+   */
   this.fileCount = 0;
+
+  /**
+   * @type {number}
+   */
   this.directoryCount = 0;
+
+  /**
+   * @type {number}
+   */
   this.bytes = 0;
+
+  /**
+   * @type {boolean}
+   */
   this.showBytes = false;
-  this.allDriveFilesPresent = false,
+
+  /**
+   * @type {boolean}
+   */
+  this.allDriveFilesPresent = false;
+
+  /**
+   * @type {?string}
+   */
   this.iconType = null;
+
+  /**
+   * @type {boolean}
+   */
   this.bytesKnown = false;
+
+  /**
+   * @type {boolean}
+   * @private
+   */
   this.mustBeHidden_ = false;
+
+  /**
+   * @type {Array.<string>}
+   */
   this.mimeTypes = null;
 
+  /**
+   * @type {!FileTasks}
+   */
+  this.tasks = new FileTasks(this.fileManager_);
+
+  /**
+   * @type {Promise}
+   * @private
+   */
+  this.asyncInitPromise_ = null;
+
   // Synchronously compute what we can.
   for (var i = 0; i < this.indexes.length; i++) {
     var entry = /** @type {!Entry} */
@@ -49,39 +122,36 @@ function FileSelection(fileManager, indexes) {
     }
     this.totalCount++;
   }
-
-  this.tasks = new FileTasks(this.fileManager_);
-
-  Object.seal(this);
 }
 
 /**
  * Computes data required to get file tasks and requests the tasks.
- *
- * @param {function()} callback The callback.
+ * @return {!Promise}
  */
-FileSelection.prototype.createTasks = function(callback) {
-  if (!this.fileManager_.isOnDrive()) {
-    this.tasks.init(this.entries);
-    callback();
-    return;
-  }
-
-  this.fileManager_.metadataCache_.get(
-      this.entries, 'external', function(props) {
+FileSelection.prototype.completeInit = function() {
+  if (!this.asyncInitPromise_) {
+    if (!this.fileManager_.isOnDrive()) {
+      this.asyncInitPromise_ = Promise.resolve();
+      this.tasks.init(this.entries);
+      this.allDriveFilesPresent = true;
+    } else {
+      this.asyncInitPromise_ = new Promise(function(fulfill) {
+        this.fileManager_.metadataCache.get(this.entries, 'external', fulfill);
+      }.bind(this)).then(function(props) {
         var present = props.filter(function(p) {
           return p && p.availableOffline;
         });
         this.allDriveFilesPresent = present.length == props.length;
-
-        // Collect all of the mime types and push that info into the selection.
+        // Collect all of the mime types and push that info into the
+        // selection.
         this.mimeTypes = props.map(function(value) {
           return (value && value.contentMimeType) || '';
         });
-
         this.tasks.init(this.entries, this.mimeTypes);
-        callback();
       }.bind(this));
+    }
+  }
+  return this.asyncInitPromise_;
 };
 
 /**
@@ -150,7 +220,7 @@ FileSelection.prototype.cancelComputing_ = function() {
 /**
  * This object encapsulates everything related to current selection.
  *
- * @param {FileManager} fileManager File manager instance.
+ * @param {!FileManager} fileManager File manager instance.
  * @extends {cr.EventTarget}
  * @constructor
  * @struct
@@ -179,6 +249,23 @@ function FileSelectionHandler(fileManager) {
 }
 
 /**
+ * @enum {string}
+ */
+FileSelectionHandler.EventType = {
+  /**
+   * Dispatched every time when selection is changed.
+   */
+  CHANGE: 'change',
+
+  /**
+   * Dispatched 200ms later after the selecton is changed.
+   * If multiple changes are happened during the term, only one CHANGE_THROTTLED
+   * event is dispatched.
+   */
+  CHANGE_THROTTLED: 'changethrottled'
+};
+
+/**
  * Create the temporary disabled action item.
  * @return {Object} Created disabled item.
  * @private
@@ -267,25 +354,27 @@ FileSelectionHandler.prototype.onFileSelectionChanged = function() {
   this.selectionUpdateTimer_ = setTimeout(function() {
     this.selectionUpdateTimer_ = null;
     if (this.selection == selection)
-      this.updateFileSelectionAsync(selection);
+      this.updateFileSelectionAsync_(selection);
   }.bind(this), updateDelay);
 
-  cr.dispatchSimpleEvent(this, 'change');
+  cr.dispatchSimpleEvent(this, FileSelectionHandler.EventType.CHANGE);
 };
 
 /**
  * Calculates async selection stats and updates secondary UI elements.
  *
  * @param {FileSelection} selection The selection object.
+ * @private
  */
-FileSelectionHandler.prototype.updateFileSelectionAsync = function(selection) {
-  if (this.selection != selection) return;
+FileSelectionHandler.prototype.updateFileSelectionAsync_ = function(selection) {
+  if (this.selection !== selection)
+    return;
 
   // Update the file tasks.
   if (this.fileManager_.dialogType === DialogType.FULL_PAGE &&
       selection.directoryCount === 0 && selection.fileCount > 0) {
-    selection.createTasks(function() {
-      if (this.selection != selection)
+    selection.completeInit().then(function() {
+      if (this.selection !== selection)
         return;
       selection.tasks.display(this.taskMenuButton_);
       selection.tasks.updateMenuItem();
@@ -308,7 +397,17 @@ FileSelectionHandler.prototype.updateFileSelectionAsync = function(selection) {
   if (this.fileManager_.commandHandler)
     this.fileManager_.commandHandler.updateAvailability();
 
-  // Inform tests it's OK to click buttons now.
-  if (selection.totalCount > 0)
-    util.testSendMessage('selection-change-complete');
+  cr.dispatchSimpleEvent(this, FileSelectionHandler.EventType.CHANGE_THROTTLED);
+};
+
+/**
+ * Returns whether all the selected files are available currently or not.
+ * Should be called after the selection initialized.
+ * @return {boolean}
+ */
+FileSelectionHandler.prototype.isAvailable = function() {
+  return !this.fileManager_.isOnDrive() ||
+      this.fileManager_.volumeManager.getDriveConnectionState().type !==
+          VolumeManagerCommon.DriveConnectionType.OFFLINE ||
+      this.selection.allDriveFilesPresent;
 };