The Tor Browser / file revision

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 const Cc = Components.classes;

 const Ci = Components.interfaces;

 Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");

 // -----------------------------------------------------------------------

 // Directory Provider for special browser folders and files

 // -----------------------------------------------------------------------

 const NS_APP_CACHE_PARENT_DIR = "cachePDir";

 function DirectoryProvider() {}

 DirectoryProvider.prototype = {

   classID: Components.ID("{ef0f7a87-c1ee-45a8-8d67-26f586e46a4b}"),

   QueryInterface: XPCOMUtils.generateQI([Ci.nsIDirectoryServiceProvider]),

   getFile: function(prop, persistent) {

     if (prop == NS_APP_CACHE_PARENT_DIR) {

       let dirsvc = Cc["@mozilla.org/file/directory_service;1"].getService(Ci.nsIProperties);

       let profile = dirsvc.get("ProfD", Ci.nsIFile);

       let sysInfo = Cc["@mozilla.org/system-info;1"].getService(Ci.nsIPropertyBag2);

       let device = sysInfo.get("device");

       switch (device) {

         default:

           return profile;

       }

     }

     // We are retuning null to show failure instead for throwing an error. The

     // interface is called quite a bit and throwing an error is noisy. Returning

     // null works with the way the interface is called [see bug 529077]

     return null;

   }

 };

 this.NSGetFactory = XPCOMUtils.generateNSGetFactory([DirectoryProvider]);