Postpone connecting to GData even more, provide progress indication.

chrome/browser/resources/file_manager/js/directory_model.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // If directory files changes too often, don't rescan directory more than once
 // per specified interval
 const SIMULTANEOUS_RESCAN_INTERVAL = 1000;
 
 /**
  * Data model of the file manager.
@@ skipping 550 matching lines @@
   },
 
   /**
    * Change the state of the model to reflect the specified path (either a
    * file or directory).
    *
    * @param {string} path The root path to use
    * @param {Function=} opt_loadedCallback Invoked when the entire directory
    *     has been loaded and any default file selected.  If there are any
    *     errors loading the directory this will not get called (even if the
-   *     directory loads OK on retry later).
+   *     directory loads OK on retry later). Will NOT be called if another
+   *     directory change happened while setupPath was in progress.
    * @param {Function=} opt_pathResolveCallback Invoked as soon as the path has
    *     been resolved, and called with the base and leaf portions of the path
-   *     name, and a flag indicating if the entry exists.
+   *     name, and a flag indicating if the entry exists. Will be called even
+   *     if another directory change happened while setupPath was in progress,
+   *     but will pass |false| as |exist| parameter.
    */
   setupPath: function(path, opt_loadedCallback, opt_pathResolveCallback) {
+    var overridden = false;
+    function onExternalDirChange() { overridden = true }
+    this.addEventListener('directory-changed', onExternalDirChange);
+
+    var resolveCallback = function(exists) {
+      this.removeEventListener('directory-changed', onExternalDirChange);
+      if (opt_pathResolveCallback)
+        opt_pathResolveCallback(baseName, leafName, exists && !overridden);

[dgozman, 2012/03/28 10:28:30]

Why do we call this in the case of overridden?

[Vladislav Kaznacheev, 2012/03/28 14:00:57]

Because the client might have to do some cleanup (e.g. hiding a shade)
On 2012/03/28 10:28:30, dgozman wrote:

+    }.bind(this);
+
+    var changeDirectoryEntry = function (entry, callback, initial, exists) {

[dgozman, 2012/03/28 10:28:30]

space before (

[Vladislav Kaznacheev, 2012/03/28 14:00:57]

Done.

+      resolveCallback(exists);
+      if (!overridden)
+        this.changeDirectoryEntry_(entry, callback, initial);
+    }.bind(this);
+
+    var INITIAL = true;
+    var EXISTS = true;
+
     // Split the dirname from the basename.
     var ary = path.match(/^(?:(.*)\/)?([^\/]*)$/);
     var autoSelect = function() {
-          this.selectIndex(this.autoSelectIndex_);
-          if (opt_loadedCallback)
-            opt_loadedCallback();
+      this.selectIndex(this.autoSelectIndex_);
+      if (opt_loadedCallback)
+        opt_loadedCallback();
     }.bind(this);
 
     if (!ary) {
       console.warn('Unable to split default path: ' + path);
-      this.changeDirectoryEntry_(this.root_, autoSelect, true);
+      changeDirectoryEntry(this.root_, autoSelect, INITIAL, !EXISTS);

[dgozman, 2012/03/28 10:28:30]

resolveCallback was not called here before. Bug?

[Vladislav Kaznacheev, 2012/03/28 14:00:57]

Yes, it was a but (there was another one in onBaseFound.
On 2012/03/28 10:28:30, dgozman wrote:

       return;
     }
 
     var baseName = ary[1];
     var leafName = ary[2];
 
-    function resolveCallback(exists) {
-      if (opt_pathResolveCallback)
-        opt_pathResolveCallback(baseName, leafName, exists);
-    }
-
     function onLeafFound(baseDirEntry, leafEntry) {
       if (leafEntry.isDirectory) {
         baseName = path;
         leafName = '';
-        resolveCallback(true);
-        this.changeDirectoryEntry_(leafEntry, autoSelect, true);
+        changeDirectoryEntry(leafEntry, autoSelect, INITIAL, EXISTS);
         return;
       }
 
-      resolveCallback(true);
       // Leaf is an existing file, cd to its parent directory and select it.
-      this.changeDirectoryEntry_(baseDirEntry,
-                                 function() {
-                                   this.selectEntry(leafEntry.name);
-                                   if (opt_loadedCallback)
-                                     opt_loadedCallback();
-                                 }.bind(this),
-                                 false /*HACK*/);
+      changeDirectoryEntry(baseDirEntry,
+                           function() {
+                             this.selectEntry(leafEntry.name);
+                             if (opt_loadedCallback)
+                               opt_loadedCallback();
+                           }.bind(this),
+                           !INITIAL /*HACK*/,
+                           EXISTS);
       // TODO(kaznacheev): Fix history.replaceState for the File Browser and
-      // change the last parameter back to |true|. Passing |false| makes things
+      // change !INITIAL to INITIAL. Passing |false| makes things
       // less ugly for now.
     }
 
     function onLeafError(baseDirEntry, err) {
-      resolveCallback(false);
       // Usually, leaf does not exist, because it's just a suggested file name.
       if (err.code != FileError.NOT_FOUND_ERR)
         console.log('Unexpected error resolving default leaf: ' + err);
-      this.changeDirectoryEntry_(baseDirEntry, autoSelect, true);
+      changeDirectoryEntry(baseDirEntry, autoSelect, INITIAL, !EXISTS);
     }
 
     var onBaseError = function(err) {
-      resolveCallback(false);
       console.log('Unexpected error resolving default base "' +
                   baseName + '": ' + err);
       if (path != '/' + DirectoryModel.DOWNLOADS_DIRECTORY) {
         // Can't find the provided path, let's go to default one instead.
-        this.setupDefaultPath(opt_loadedCallback);
+        resolveCallback(!EXISTS);
+        if (!overridden)
+          this.setupDefaultPath(opt_loadedCallback);
       } else {
         // Well, we can't find the downloads dir. Let's just show something,
         // or we will get an infinite recursion.
-        this.changeDirectoryEntry_(this.root_, opt_loadedCallback, true);
+        changeDirectoryEntry(this.root_, opt_loadedCallback, INITIAL, !EXISTS);
       }
     }.bind(this);
 
     var onBaseFound = function(baseDirEntry) {
       if (!leafName) {
         // Default path is just a directory, cd to it and we're done.
-        this.changeDirectoryEntry_(baseDirEntry, autoSelect, true);
+        changeDirectoryEntry(baseDirEntry, autoSelect, INITIAL, !EXISTS);
         return;
       }
 
       util.resolvePath(this.root_, path,
                        onLeafFound.bind(this, baseDirEntry),
                        onLeafError.bind(this, baseDirEntry));
     }.bind(this);
 
     var root = this.root_;
     if (baseName) {
       root.getDirectory(
           baseName, {create: false}, onBaseFound, onBaseError);
     } else {
       this.getDefaultDirectory_(function(defaultDir) {
         baseName = defaultDir;
         root.getDirectory(
             baseName, {create: false}, onBaseFound, onBaseError);
       });
     }
   },
 
   setupDefaultPath: function(opt_callback) {
+    var overridden = false;
+    function onExternalDirChange() { overridden = true }
+    this.addEventListener('directory-changed', onExternalDirChange);
+
     this.getDefaultDirectory_(function(path) {
-      this.setupPath(path, opt_callback);
+      this.removeEventListener('directory-changed', onExternalDirChange);
+      if (!overridden)
+        this.setupPath(path, opt_callback);
     }.bind(this));
   },
 
   getDefaultDirectory_: function(callback) {
     function onGetDirectoryComplete(entries, error) {
       if (entries.length > 0)
         callback(entries[0].fullPath);
       else
         callback('/' + DirectoryModel.DOWNLOADS_DIRECTORY);
     }
@@ skipping 65 matching lines @@
     function onCacheDone() {
       waitCount--;
       // If all caching functions finished synchronously or entries.length = 0
       // call the callback synchronously.
       if (waitCount == 0)
         setTimeout(callback, 0);
     }
   },
 
   /**
-   * Get root entries asynchronously. Invokes callback
-   * when have finished.
+   * Get root entries asynchronously.
+   * @param {function(Array.<Entry>} callback Called when roots are resolved.
+   * @param {boolean} resolveGData See comment for updateRoots.
    */
-  resolveRoots_: function(callback) {
+  resolveRoots_: function(callback, resolveGData) {
     var groups = {
       downloads: null,
       archives: null,
       removables: null,
       gdata: null
     };
 
     metrics.startInterval('Load.Roots');
     function done() {
       for (var i in groups)
@@ skipping 18 matching lines @@
     }
 
     function onDownloadsError(error) {
       groups.downloads = [];
       done();
     }
 
     var self = this;
 
     function onGData(entry) {
-      console.log('onGData');
-      console.log(entry);
+      console.log('GData found:', entry);
       self.unmountedGDataEntry_ = null;
       groups.gdata = [entry];
       done();
     }
 
     function onGDataError(error) {
-      console.log('onGDataError');
-      console.log(error);
+      console.log('GData error: ', error);
       self.unmountedGDataEntry_ = {
+        unmounted: true,  // Clients use this field to distinguish a fake root.
+        toURL: function() { return '' },
         fullPath: '/' + DirectoryModel.GDATA_DIRECTORY
       };
       groups.gdata = [self.unmountedGDataEntry_];
       done();
     }
 
     var root = this.root_;
     root.getDirectory(DirectoryModel.DOWNLOADS_DIRECTORY, { create: false },
                       onDownloads, onDownloadsError);
     util.readDirectory(root, DirectoryModel.ARCHIVE_DIRECTORY,
                        append.bind(this, 'archives'));
     util.readDirectory(root, DirectoryModel.REMOVABLE_DIRECTORY,
                        append.bind(this, 'removables'));
     if (this.showGData_) {
-      root.getDirectory(DirectoryModel.GDATA_DIRECTORY, { create: false },
-                        onGData, onGDataError);
+      if (resolveGData) {
+        root.getDirectory(DirectoryModel.GDATA_DIRECTORY, { create: false },
+                          onGData, onGDataError);
+      } else {
+        onGDataError('lazy mount');
+      }
     } else {
       groups.gdata = [];
     }
   },
 
-  updateRoots: function(opt_callback) {
-    console.log('directoryModel_.updateRoots');
+  /**
+  * @param {function} opt_callback Called when all roots are resolved.
+  * @param {boolean} opt_resolveGData If true GData should be resolved for real,
+  *                                   If false a stub entry should be created.
+  */
+  updateRoots: function(opt_callback, opt_resolveGData) {
+    console.log('resolving roots');
     var self = this;
     this.resolveRoots_(function(rootEntries) {
-      console.log('rootsList_ = ');
-      console.log(self.rootsList_);
+      console.log('resolved roots:', rootEntries);
       var dm = self.rootsList_;
       var args = [0, dm.length].concat(rootEntries);
       dm.splice.apply(dm, args);
 
       self.updateRootsListSelection_();
 
       if (opt_callback)
         opt_callback();
-    });
+    }, opt_resolveGData);
   },
 
   onRootsSelectionChanged_: function(event) {
     var root = this.rootsList.item(this.rootsListSelection.selectedIndex);
-    var current = this.currentEntry.fullPath;
     if (root && this.rootPath != root.fullPath)
       this.changeDirectory(root.fullPath);
   },
 
   updateRootsListSelection_: function() {
     var roots = this.rootsList_;
     var rootPath = this.rootPath;
     for (var index = 0; index < roots.length; index++) {
       if (roots.item(index).fullPath == rootPath) {
         this.rootsListSelection.selectedIndex = index;
@@ skipping 129 matching lines @@
 
   recordMetrics_: function() {
     metrics.recordInterval('DirectoryScan');
     if (this.dir_.fullPath ==
         '/' + DirectoryModel.DOWNLOADS_DIRECTORY) {
       metrics.recordMediumCount("DownloadsCount", this.list_.length);
     }
   }
 };