/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is the Update Service.
 *
 * The Initial Developer of the Original Code is Ben Goodger.
 * Portions created by the Initial Developer are Copyright (C) 2004
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *  Ben Goodger <ben@bengoodger.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

const PREF_UPDATE_APP_ENABLED               = "app.update.enabled";
const PREF_UPDATE_APP_AUTOUPDATEENABLED     = "app.update.autoUpdateEnabled";
const PREF_UPDATE_APP_URI                   = "app.update.url";
const PREF_UPDATE_APP_UPDATESAVAILABLE      = "app.update.updatesAvailable";
const PREF_UPDATE_APP_INTERVAL              = "app.update.interval";
const PREF_UPDATE_APP_LASTUPDATEDATE        = "app.update.lastUpdateDate";
const PREF_UPDATE_APP_PERFORMED             = "app.update.performed";

const PREF_UPDATE_EXTENSIONS_ENABLED            = "extensions.update.enabled";
const PREF_UPDATE_EXTENSIONS_AUTOUPDATEENABLED  = "extensions.update.autoUpdateEnabled";
const PREF_UPDATE_EXTENSIONS_AUTOUPDATE         = "extensions.update.autoUpdate";
const PREF_UPDATE_EXTENSIONS_COUNT              = "extensions.update.count";
const PREF_UPDATE_EXTENSIONS_INTERVAL           = "extensions.update.interval";
const PREF_UPDATE_EXTENSIONS_LASTUPDATEDATE     = "extensions.update.lastUpdateDate";
const PREF_UPDATE_EXTENSIONS_SEVERITY_THRESHOLD = "extensions.update.severity.threshold";

const PREF_UPDATE_INTERVAL                  = "update.interval";
const PREF_UPDATE_SEVERITY                  = "update.severity";
const PREF_UPDATE_SHOW_SLIDING_NOTIFICATION = "update.showSlidingNotification";

const nsIExtensionManager = Components.interfaces.nsIExtensionManager;
const nsIUpdateService    = Components.interfaces.nsIUpdateService;
const nsIUpdateItem       = Components.interfaces.nsIUpdateItem;

const UPDATED_EXTENSIONS  = 0x01;
const UPDATED_APP         = 0x02;

function APP_NS(aProperty)
{
  return "http://www.mozilla.org/2004/app-rdf#" + aProperty;
}

function getOSKey()
{
  return "windows";
}

function stackTraceFunctionFormat(aFunctionName)
{
  var classDelimiter = aFunctionName.indexOf("_");
  var className = aFunctionName.substr(0, classDelimiter);
  if (!className)
    className == "<global>";
  var functionName = aFunctionName.substr(classDelimiter + 1, aFunctionName.length);
  if (!functionName) 
    functionName == "<anonymous>";
  return className + "::" + functionName;
}

function stackTrace(aArguments, aMaxCount)
{
  dump("=[STACKTRACE]=====================================================\n");
  dump("*** at: " + stackTraceFunctionFormat(aArguments.callee.name) + "()\n");
  var temp = aArguments.callee.caller;
  var count = 0;
  while (temp) {
    dump("***     " + stackTraceFunctionFormat(temp.name) + ")\n");
    temp = temp.arguments.callee.caller;
    if (aMaxCount > 0 && ++count == aMaxCount)
      break;
  }
  dump("==================================================================\n");
}

var gApp    = null;
var gPref   = null;
var gOS     = null;
var gRDF    = null;

function nsUpdateService()
{
  gApp  = Components.classes["@mozilla.org/xre/app-info;1"]
                    .getService(Components.interfaces.nsIXULAppInfo);
  gPref = Components.classes["@mozilla.org/preferences-service;1"]
                    .getService(Components.interfaces.nsIPrefBranch);
  gOS   = Components.classes["@mozilla.org/observer-service;1"]
                    .getService(Components.interfaces.nsIObserverService);
  gRDF  = Components.classes["@mozilla.org/rdf/rdf-service;1"]
                    .getService(Components.interfaces.nsIRDFService);
  
  this.watchForUpdates();

  var pbi = gPref.QueryInterface(Components.interfaces.nsIPrefBranchInternal);
  pbi.addObserver(PREF_UPDATE_APP_AUTOUPDATEENABLED, this, false);
  pbi.addObserver(PREF_UPDATE_APP_ENABLED, this, false);
  pbi.addObserver(PREF_UPDATE_EXTENSIONS_AUTOUPDATEENABLED, this, false);
  pbi.addObserver(PREF_UPDATE_EXTENSIONS_ENABLED, this, false);
  pbi.addObserver(PREF_UPDATE_INTERVAL, this, false);
  pbi.addObserver(PREF_UPDATE_APP_INTERVAL, this, false);
  pbi.addObserver(PREF_UPDATE_EXTENSIONS_INTERVAL, this, false);

  // Observe xpcom-shutdown to unhook pref branch observers above to avoid 
  // shutdown leaks.
  gOS.addObserver(this, "xpcom-shutdown", false);
  
  // Reset update state from previous session if an app update was installed.
  if (gPref.prefHasUserValue(PREF_UPDATE_APP_PERFORMED)) 
    gPref.clearUserPref(PREF_UPDATE_APP_PERFORMED);
}

nsUpdateService.prototype = {
  _updateObserver: null,
  _appAutoUpdateEnabled: true,
  _extAutoUpdateEnabled: true,
    
  /////////////////////////////////////////////////////////////////////////////
  // nsIUpdateService
  watchForUpdates: function nsUpdateService_watchForUpdates ()
  {
    // This is called when the app starts, so check to see if the time interval
    // expired between now and the last time an automated update was performed.
    // now is the same one that was started last time. 
    this._appAutoUpdateEnabled = gPref.getBoolPref(PREF_UPDATE_APP_AUTOUPDATEENABLED);
    this._extAutoUpdateEnabled = gPref.getBoolPref(PREF_UPDATE_EXTENSIONS_AUTOUPDATEENABLED);
    if (!this._appAutoUpdateEnabled && !this._extAutoUpdateEnabled)
      return;

    this._makeTimer(gPref.getIntPref(PREF_UPDATE_INTERVAL));
  },
  
  _getAllowedTypes: function nsUpdateService__getAllowedTypes(aRequestedTypes)
  {
    // Figure out what types we're allowed to update. These options
    // differ from PREF_UPDATE_*_AUTOUPDATEENABLED since they effectively
    // shut down the update UI if the administrator/distributor has configured
    // a build to have disallowed these types of update.
    var extUpdateEnabled = gPref.getBoolPref(PREF_UPDATE_EXTENSIONS_ENABLED);
    var appUpdateEnabled = gPref.getBoolPref(PREF_UPDATE_APP_ENABLED);
    
    var types = 0;
    if (extUpdateEnabled) {
      if (aRequestedTypes & nsIUpdateItem.TYPE_EXTENSION)
        types |= nsIUpdateItem.TYPE_EXTENSION;
      if (aRequestedTypes & nsIUpdateItem.TYPE_THEME)
        types |= nsIUpdateItem.TYPE_THEME;
    }
    if (appUpdateEnabled && 
        (aRequestedTypes & nsIUpdateItem.TYPE_APP))
      types |= nsIUpdateItem.TYPE_APP;

    return types;
  },
  
  checkForUpdates: function nsUpdateService_checkForUpdates (aItems, aItemCount, aUpdateTypes, aSourceEvent, aParentWindow)
  {
    var types = this._getAllowedTypes(aUpdateTypes);
    
    // Nothing to update
    if (!types) {
      var sbs = Components.classes["@mozilla.org/intl/stringbundle;1"]
                          .getService(Components.interfaces.nsIStringBundleService);
      var bundle = sbs.createBundle("chrome://mozapps/locale/update/update.properties");
      var ps = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
                         .getService(Components.interfaces.nsIPromptService);
      ps.alert(aParentWindow, 
               bundle.GetStringFromName("updatesdisabledtitle"), 
               bundle.GetStringFromName("updatesdisabledmessage"));
      return;
    }
  
    switch (aSourceEvent) {
    case nsIUpdateService.SOURCE_EVENT_MISMATCH:
    case nsIUpdateService.SOURCE_EVENT_USER:
      if (aSourceEvent == nsIUpdateService.SOURCE_EVENT_USER && 
          gPref.getBoolPref(PREF_UPDATE_APP_PERFORMED)) {
        var sbs = Components.classes["@mozilla.org/intl/stringbundle;1"]
                            .getService(Components.interfaces.nsIStringBundleService);
        var bundle = sbs.createBundle("chrome://mozapps/locale/update/update.properties");
        var brandBundle = sbs.createBundle("chrome://global/locale/brand.properties");
        var brandShortName = brandBundle.GetStringFromName("brandShortName");        
        var message = bundle.formatStringFromName("appupdateperformedmessage",
                                                  [brandShortName, brandShortName], 2);
        var ps = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
                          .getService(Components.interfaces.nsIPromptService);
        ps.alert(aParentWindow, 
                 bundle.GetStringFromName("appupdateperformedtitle"), 
                 message);
        return;
      }
      
      var wm = Components.classes["@mozilla.org/appshell/window-mediator;1"]
                         .getService(Components.interfaces.nsIWindowMediator);
      var wizard = wm.getMostRecentWindow("Update:Wizard");
      if (wizard)
        wizard.focus();
      else {
        var ww = Components.classes["@mozilla.org/embedcomp/window-watcher;1"]
                          .getService(Components.interfaces.nsIWindowWatcher);
        var ary = Components.classes["@mozilla.org/supports-array;1"]
                            .createInstance(Components.interfaces.nsISupportsArray);
        var updateTypes = Components.classes["@mozilla.org/supports-PRUint8;1"]
                                    .createInstance(Components.interfaces.nsISupportsPRUint8);
        updateTypes.data = types;
        ary.AppendElement(updateTypes);
        var sourceEvent = Components.classes["@mozilla.org/supports-PRUint8;1"]
                                    .createInstance(Components.interfaces.nsISupportsPRUint8);
        sourceEvent.data = aSourceEvent;
        ary.AppendElement(sourceEvent);
        for (var i = 0; i < aItems.length; ++i)
          ary.AppendElement(aItems[i]);

        var features = "chrome,centerscreen";
        if (aSourceEvent == nsIUpdateService.SOURCE_EVENT_MISMATCH) {
          features += ",modal"; // Must block in mismatch mode since there's 
                                // no main evt loop yet. 
        }
        // This *must* be modal so as not to break startup! This code is invoked before
        // the main event loop is initiated (via checkForMismatches).
        ww.openWindow(aParentWindow, "chrome://mozapps/content/update/update.xul", 
                      "", features, ary);
      }
      break;
    case nsIUpdateService.SOURCE_EVENT_BACKGROUND:
      // Rather than show a UI, call the checkForUpdates function directly here. 
      // The Browser's inline front end update notification system listens for the
      // updates that this function broadcasts.
      this.checkForUpdatesInternal([], 0, types, aSourceEvent);

      break;
    }  
  },
  
  _canUpdate: function (aPreference, aSourceEvent, aUpdateTypes)
  {
    // Always can update if the autoupdate preference is set, otherwise, 
    // allow updates only when not in backround update mode, i.e. when the user
    // explicitly asked. 
    return aPreference ? true 
                       : aSourceEvent != nsIUpdateService.SOURCE_EVENT_BACKGROUND;
  },
  
  checkForUpdatesInternal: function nsUpdateService_checkForUpdatesInternal (aItems, aItemCount, aUpdateTypes, aSourceEvent)
  {
    var types = this._getAllowedTypes(aUpdateTypes);

    // Listen for notifications sent out by the app updater (implemented here) and the
    // extension updater (implemented in nsExtensionItemUpdater)
    var canUpdate;
    this._updateObserver = new nsUpdateObserver(types, aSourceEvent, this);
    var os = Components.classes["@mozilla.org/observer-service;1"]
                       .getService(Components.interfaces.nsIObserverService);
    if (types & nsIUpdateItem.TYPE_APP) {
      if (this._canUpdate(this._appAutoUpdateEnabled, aSourceEvent, types)) {
        gOS.addObserver(this._updateObserver, "Update:App:Ended", false);
        
        this._currentVersion  = new nsAppUpdateInfo();
        this._newestVersion   = new nsAppUpdateInfo();

        if (!this._updateObserver.appUpdater) {
          this._updateObserver.appUpdater = new nsAppUpdater(this);
          this._updateObserver.appUpdater.checkForUpdates();
        }
      }
    }
    if (types & nsIUpdateItem.TYPE_ADDON) { // TYPE_EXTENSION, TYPE_ANY, etc.
      if (this._canUpdate(this._extAutoUpdateEnabled, aSourceEvent, types)) {
        gOS.addObserver(this._updateObserver, "Update:Extension:Started", false);
        gOS.addObserver(this._updateObserver, "Update:Extension:Item-Ended", false);
        gOS.addObserver(this._updateObserver, "Update:Extension:Ended", false);

        var em = Components.classes["@mozilla.org/extensions/manager;1"]
                           .getService(Components.interfaces.nsIExtensionManager);
        em.update(aItems, aItems.length, false);
      }
    }
    
    if (aSourceEvent == nsIUpdateService.SOURCE_EVENT_BACKGROUND && 
        (this._appAutoUpdateEnabled || this._extAutoUpdateEnabled)) {
      if (types & nsIUpdateItem.TYPE_ADDON)
        gPref.setIntPref(PREF_UPDATE_EXTENSIONS_LASTUPDATEDATE, this._nowInMilliseconds / 1000);
      if (types & nsIUpdateItem.TYPE_APP)
        gPref.setIntPref(PREF_UPDATE_APP_LASTUPDATEDATE, this._nowInMilliseconds / 1000);
    }
  },
  
  get updateCount()
  {
    // The number of available updates is the number of extension/theme/other
    // updates + 1 for an application update, if one is available.
    var updateCount = this.extensionUpdatesAvailable;
    if (this.appUpdatesAvailable)
      ++updateCount;
    return updateCount;
  },
  
  get updateSeverity()
  {
    return gPref.getIntPref(PREF_UPDATE_SEVERITY);
  },
  
  _appUpdatesAvailable: undefined,
  get appUpdatesAvailable() 
  {
    if (this._appUpdatesAvailable === undefined) {
      return (gPref.prefHasUserValue(PREF_UPDATE_APP_UPDATESAVAILABLE) && 
              gPref.getBoolPref(PREF_UPDATE_APP_UPDATESAVAILABLE));
    }
    return this._appUpdatesAvailable;
  },
  set appUpdatesAvailable(aValue)
  {
    this._appUpdatesAvailable = aValue;
    return aValue;
  },
  
  _extensionUpdatesAvailable: undefined,
  get extensionUpdatesAvailable()
  {
    if (this._extensionUpdatesAvailable === undefined)
      return gPref.getIntPref(PREF_UPDATE_EXTENSIONS_COUNT);
    return this._extensionUpdatesAvailable;
  },
  set extensionUpdatesAvailable(aValue)
  {
    this._extensionUpdatesAvailable = aValue;
    return aValue;
  },
  
  _newestVersion: null,
  get newestVersion()
  {
    return this._newestVersion;
  },
  _currentVersion: null,
  get currentVersion()
  {
    return this._currentVersion;
  },
    
  /////////////////////////////////////////////////////////////////////////////
  // nsITimerCallback
  _shouldUpdate: function nsUpdateService__shouldUpdate (aIntervalPref, aLastCheckPref)
  {
    var interval = gPref.getIntPref(aIntervalPref);
    var lastUpdateTime = gPref.getIntPref(aLastCheckPref);
    return ((Math.round(this._nowInMilliseconds/1000) - lastUpdateTime) > Math.round(interval/1000));
  },
  
  notify: function nsUpdateService_notify (aTimer)
  {
    var types = 0;
    if (this._shouldUpdate(PREF_UPDATE_EXTENSIONS_INTERVAL, 
                           PREF_UPDATE_EXTENSIONS_LASTUPDATEDATE)) {
      types |= nsIUpdateItem.TYPE_ADDON;         
    }
    if (this._shouldUpdate(PREF_UPDATE_APP_INTERVAL,
                           PREF_UPDATE_APP_LASTUPDATEDATE)) {
      types |= nsIUpdateItem.TYPE_APP;         
    }
    if (types)
      this.checkForUpdatesInternal([], 0, types, 
                                   nsIUpdateService.SOURCE_EVENT_BACKGROUND);
  },

  /////////////////////////////////////////////////////////////////////////////
  // nsIObserver
  observe: function nsUpdateService_observe (aSubject, aTopic, aData)
  {
    switch (aTopic) {
    case "nsPref:changed":
      var needsNotification = false;
      switch (aData) {
      case PREF_UPDATE_APP_AUTOUPDATEENABLED:
      case PREF_UPDATE_APP_ENABLED:
        this._appAutoUpdateEnabled = gPref.getBoolPref(PREF_UPDATE_APP_AUTOUPDATEENABLED);
        if (!this._appAutoUpdateEnabled) {
          this._clearAppUpdatePrefs();
          needsNotification = true;
        }
        else {
          // Do an initial check NOW to update any FE components and kick off the
          // timer. 
          this.checkForUpdatesInternal([], 0, nsIUpdateItem.TYPE_APP, 
                                       nsIUpdateService.SOURCE_EVENT_BACKGROUND);
        }
        break;
      case PREF_UPDATE_EXTENSIONS_AUTOUPDATEENABLED:
      case PREF_UPDATE_EXTENSIONS_ENABLED:
        this._extAutoUpdateEnabled = gPref.getBoolPref(PREF_UPDATE_EXTENSIONS_AUTOUPDATEENABLED);
        if (!this._extAutoUpdateEnabled) {
          // Unset prefs used by the update service to signify extension updates
          if (gPref.prefHasUserValue(PREF_UPDATE_EXTENSIONS_COUNT))
            gPref.clearUserPref(PREF_UPDATE_EXTENSIONS_COUNT);
          needsNotification = true;
        }
        else {
          // Do an initial check NOW to update any FE components and kick off the
          // timer. 
          this.checkForUpdatesInternal([], 0, nsIUpdateItem.TYPE_ADDON, 
                                       nsIUpdateService.SOURCE_EVENT_BACKGROUND);
        }
        break;
      case PREF_UPDATE_INTERVAL:
      case PREF_UPDATE_APP_INTERVAL:
      case PREF_UPDATE_EXTENSIONS_INTERVAL:
        this._makeTimer(gPref.getIntPref(PREF_UPDATE_INTERVAL));
        break;
      }
    
      if (needsNotification) {
        var os = Components.classes["@mozilla.org/observer-service;1"]
                           .getService(Components.interfaces.nsIObserverService);
        var backgroundEvt = Components.interfaces.nsIUpdateService.SOURCE_EVENT_BACKGROUND;
        gOS.notifyObservers(null, "Update:Ended", backgroundEvt.toString());
      }
      break;
    case "xpcom-shutdown":
      gOS.removeObserver(this, "xpcom-shutdown");    
      
      // Clean up held observers etc to avoid leaks. 
      var pbi = gPref.QueryInterface(Components.interfaces.nsIPrefBranchInternal);
      pbi.removeObserver(PREF_UPDATE_APP_AUTOUPDATEENABLED, this);
      pbi.removeObserver(PREF_UPDATE_APP_ENABLED, this);
      pbi.removeObserver(PREF_UPDATE_EXTENSIONS_AUTOUPDATEENABLED, this);
      pbi.removeObserver(PREF_UPDATE_EXTENSIONS_ENABLED, this);
      pbi.removeObserver(PREF_UPDATE_INTERVAL, this);
      pbi.removeObserver(PREF_UPDATE_EXTENSIONS_INTERVAL, this);
    
      // Release strongly held services.
      gPref = null;
      gRDF  = null;
      gOS   = null;
      if (this._timer) {
        this._timer.cancel();
        this._timer = null;
      }
      break;
    }  
  },

  /////////////////////////////////////////////////////////////////////////////
  // nsUpdateService
  _timer: null,
  _makeTimer: function nsUpdateService__makeTimer (aDelay)
  {
    if (!this._timer) 
      this._timer = Components.classes["@mozilla.org/timer;1"]
                              .createInstance(Components.interfaces.nsITimer);
    this._timer.cancel();
    this._timer.initWithCallback(this, aDelay, 
                                 Components.interfaces.nsITimer.TYPE_REPEATING_SLACK);
  },
  
  get _nowInMilliseconds ()
  {
    var d = new Date();
    return Date.UTC(d.getUTCFullYear(), 
                    d.getUTCMonth(),
                    d.getUTCDate(),
                    d.getUTCHours(),
                    d.getUTCMinutes(),
                    d.getUTCSeconds(),
                    d.getUTCMilliseconds());
  },
  
  _clearAppUpdatePrefs: function nsUpdateService__clearAppUpdatePrefs ()
  {
    // Unset prefs used by the update service to signify application updates
    if (gPref.prefHasUserValue(PREF_UPDATE_APP_UPDATESAVAILABLE))
      gPref.clearUserPref(PREF_UPDATE_APP_UPDATESAVAILABLE);
  },

  /////////////////////////////////////////////////////////////////////////////
  // nsISupports
  QueryInterface: function nsUpdateService_QueryInterface (aIID) 
  {
    if (!aIID.equals(Components.interfaces.nsIUpdateService) &&
        !aIID.equals(Components.interfaces.nsIObserver) && 
        !aIID.equals(Components.interfaces.nsISupports))
      throw Components.results.NS_ERROR_NO_INTERFACE;
    return this;
  }
};

function nsUpdateObserver(aUpdateTypes, aSourceEvent, aService)
{
  this._updateTypes = aUpdateTypes;
  this._sourceEvent = aSourceEvent;
  this._service = aService;
}

nsUpdateObserver.prototype = {
  _updateTypes: 0,
  _sourceEvent: 0,
  _updateState: 0,
  _endedTimer : null,
  
  appUpdater: null,
  
  get _doneUpdating()
  {
    var notBackground = this._sourceEvent != nsIUpdateService.SOURCE_EVENT_BACKGROUND;
    var canUpdateApp = this._service._appAutoUpdateEnabled || 
                        (notBackground ? gPref.getBoolPref(PREF_UPDATE_APP_ENABLED) 
                                       : false);
    var canUpdateExt = this._service._extAutoUpdateEnabled || 
                        (notBackground ? gPref.getBoolPref(PREF_UPDATE_EXTENSIONS_ENABLED) 
                                       : false);
   
    var test = 0;
    var updatingApp = (this._updateTypes & nsIUpdateItem.TYPE_APP) && 
                       canUpdateApp;
    var updatingExt = (this._updateTypes & nsIUpdateItem.TYPE_ADDON) &&
                       canUpdateExt;
    
    if (updatingApp)
      test |= UPDATED_APP;
    if (updatingExt)
      test |= UPDATED_EXTENSIONS;
    
    return (this._updateState & test) == test;
  },
  
  /////////////////////////////////////////////////////////////////////////////
  // nsIObserver
  observe: function nsUpdateObserver_observe (aSubject, aTopic, aData)
  {
    switch (aTopic) {
    case "Update:Extension:Started":
      // Reset the count
      gPref.setIntPref(PREF_UPDATE_EXTENSIONS_COUNT, 0);
      break;
    case "Update:Extension:Item-Ended":
      var newCount = gPref.getIntPref(PREF_UPDATE_EXTENSIONS_COUNT) + 1;
      gPref.setIntPref(PREF_UPDATE_EXTENSIONS_COUNT, newCount);
      var threshold = gPref.getIntPref(PREF_UPDATE_EXTENSIONS_SEVERITY_THRESHOLD);
      if (this._service.updateSeverity < nsIUpdateService.SEVERITY_HIGH) {
        if (newCount > threshold)
          gPref.setIntPref(PREF_UPDATE_SEVERITY, nsIUpdateService.SEVERITY_MEDIUM);
        else
          gPref.setIntPref(PREF_UPDATE_SEVERITY, nsIUpdateService.SEVERITY_LOW);
      }
      break;
    case "Update:Extension:Ended":
      this._updateState |= UPDATED_EXTENSIONS;
      break;
    case "Update:App:Ended":
      this._updateState |= UPDATED_APP;
      
      this.appUpdater.destroy();
      this.appUpdater = null;
      break;
    }
    
    if (this._doneUpdating) {
      // Do the finalize stuff on a timer to let other observers have a chance to
      // handle
      if (this._endedTimer)
        this._endedTimer.cancel();
      this._endedTimer = Components.classes["@mozilla.org/timer;1"]
                                   .createInstance(Components.interfaces.nsITimer);
      this._endedTimer.initWithCallback(this, 0, 
                                        Components.interfaces.nsITimer.TYPE_ONE_SHOT);
    }
  },
  
  notify: function nsUpdateObserver_notify (aTimer)
  {
    // The Inline Browser Update UI uses this notification to refresh its update 
    // UI if necessary.
    gOS.notifyObservers(null, "Update:Ended", this._sourceEvent.toString());

    // Show update notification UI if:
    // We were updating any types and any item was found
    // We were updating extensions and an extension update was found.
    // We were updating app and an app update was found. 
    var updatesAvailable = (((this._updateTypes & nsIUpdateItem.TYPE_EXTENSION) || 
                              (this._updateTypes & nsIUpdateItem.TYPE_ANY)) && 
                            gPref.getIntPref(PREF_UPDATE_EXTENSIONS_COUNT) != 0);
    if (!updatesAvailable) {
      updatesAvailable = ((this._updateTypes & nsIUpdateItem.TYPE_APP) || 
                          (this._updateTypes & nsIUpdateItem.TYPE_ANY)) && 
                          gPref.getBoolPref(PREF_UPDATE_APP_UPDATESAVAILABLE);
    }
    
    var showNotification = gPref.getBoolPref(PREF_UPDATE_SHOW_SLIDING_NOTIFICATION);
    if (showNotification && updatesAvailable && 
        this._sourceEvent == nsIUpdateService.SOURCE_EVENT_BACKGROUND) {
      var sbs = Components.classes["@mozilla.org/intl/stringbundle;1"]
                          .getService(Components.interfaces.nsIStringBundleService);
      var bundle = sbs.createBundle("chrome://mozapps/locale/update/update.properties");

      var alertTitle = bundle.GetStringFromName("updatesAvailableTitle");
      var alertText = bundle.GetStringFromName("updatesAvailableText");
      
      var alerts = Components.classes["@mozilla.org/alerts-service;1"]
                            .getService(Components.interfaces.nsIAlertsService);
      alerts.showAlertNotification("chrome://mozapps/skin/xpinstall/xpinstallItemGeneric.png",
                                    alertTitle, alertText, true, "", this);
    }

    this.destroy();
  },

  destroy: function nsUpdateObserver_destroy ()
  {
    try { gOS.removeObserver(this, "Update:Extension:Started");    } catch (e) { }
    try { gOS.removeObserver(this, "Update:Extension:Item-Ended"); } catch (e) { }
    try { gOS.removeObserver(this, "Update:Extension:Ended");      } catch (e) { }
    try { gOS.removeObserver(this, "Update:App:Ended");            } catch (e) { }
    
    if (this._endedTimer) {
      this._endedTimer.cancel();
      this._endedTimer = null;
    }
  },

  ////////////////////////////////////////////////////////////////////////////
  // nsIAlertListener
  onAlertFinished: function nsUpdateObserver_onAlertFinished ()
  {
  },
  
  onAlertClickCallback: function nsUpdateObserver_onAlertClickCallback (aCookie)
  {
    var updates = Components.classes["@mozilla.org/updates/update-service;1"]
                            .getService(Components.interfaces.nsIUpdateService);
    updates.checkForUpdates([], 0, Components.interfaces.nsIUpdateItem.TYPE_ANY, 
                            Components.interfaces.nsIUpdateService.SOURCE_EVENT_USER,
                            null);
  },
  
  /////////////////////////////////////////////////////////////////////////////
  // nsISupports
  QueryInterface: function nsUpdateObserver_QueryInterface (aIID) 
  {
    if (!aIID.equals(Components.interfaces.nsIObserver) &&
        !aIID.equals(Components.interfaces.nsIAlertListener) && 
        !aIID.equals(Components.interfaces.nsISupports))
      throw Components.results.NS_ERROR_NO_INTERFACE;
    return this;
  }
};

///////////////////////////////////////////////////////////////////////////////
// App Updater
function nsAppUpdater(aUpdateService)
{
  this._service = aUpdateService;
}

nsAppUpdater.prototype = {
  _service    : null,

  checkForUpdates: function ()
  {
    var dsURI = gPref.getComplexValue(PREF_UPDATE_APP_URI, 
                                      Components.interfaces.nsIPrefLocalizedString).data;
    dsURI += "?" + Math.round(Math.random() * 1000);
    this._ds = gRDF.GetDataSource(dsURI);
    var rds = this._ds.QueryInterface(Components.interfaces.nsIRDFRemoteDataSource)
    if (rds.loaded)
      this.onDatasourceLoaded(this._ds);
    else {
      var sink = this._ds.QueryInterface(Components.interfaces.nsIRDFXMLSink);
      
      // Creates a strong ref that holds this object past when it falls out of
      // scope in the calling function
      sink.addXMLSinkObserver(this);
    }
  },
  
  destroy: function ()
  {
    var sink = this._ds.QueryInterface(Components.interfaces.nsIRDFXMLSink);
    sink.removeXMLSinkObserver(this);
    this._service = null;
  },
  
  /////////////////////////////////////////////////////////////////////////////
  //
  _ncR: function nsUpdateService__ncR (aProperty)
  {
    return gRDF.GetResource("http://home.netscape.com/NC-rdf#" + aProperty);
  },
  
  _getPropertyFromResource: function nsAppUpdater__getPropertyFromResource (aDataSource,
                                                                            aSourceResource, 
                                                                            aProperty)
  {
    var rv;
    try {
      var property = gRDF.GetResource(APP_NS(aProperty));
      rv = this._stringData(aDataSource.GetTarget(aSourceResource, property, true));
      if (rv == "--")
        throw Components.results.NS_ERROR_FAILURE;
    }
    catch (e) { 
      return null;
    }
    return rv;
  },

  _stringData: function nsAppUpdater__stringData (aLiteralOrResource)
  {
    try {
      var obj = aLiteralOrResource.QueryInterface(Components.interfaces.nsIRDFLiteral);
      return obj.Value;
    }
    catch (e) {
      try {
        obj = aLiteralOrResource.QueryInterface(Components.interfaces.nsIRDFResource);
        return obj.Value;
      }
      catch (e) {}
    }
    return "--";
  },

  /////////////////////////////////////////////////////////////////////////////
  //
  onDatasourceLoaded: function nsAppUpdater_onDatasourceLoaded (aDataSource)
  {
    var appID = gApp.ID;
    var appVersion = gApp.version;
    
    var appResource = gRDF.GetResource("urn:mozilla:app:" + appID);
    var updatesArc = gRDF.GetResource(APP_NS("updates"));
    var updatesResource = aDataSource.GetTarget(appResource, updatesArc, true);
    
    try {
      updatesResource = updatesResource.QueryInterface(Components.interfaces.nsIRDFResource);
    }
    catch (e) { 
      gOS.notifyObservers(null, "Update:App:Error", "");
      gOS.notifyObservers(null, "Update:App:Ended", "");
      return; 
    }
    
    var cu = Components.classes["@mozilla.org/rdf/container-utils;1"]
                       .getService(Components.interfaces.nsIRDFContainerUtils);
    if (cu.IsContainer(aDataSource, updatesResource)) {
      var c = Components.classes["@mozilla.org/rdf/container;1"]
                        .getService(Components.interfaces.nsIRDFContainer);
      c.Init(aDataSource, updatesResource);
      
      var versionChecker = Components.classes["@mozilla.org/updates/version-checker;1"]
                                     .getService(Components.interfaces.nsIVersionChecker);
      
      var newestVersionObj = { version: appVersion, resource: null };
      var updates = c.GetElements();
      while (updates.hasMoreElements()) {
        var update = updates.getNext().QueryInterface(Components.interfaces.nsIRDFResource);
        var version = this._getPropertyFromResource(aDataSource, update, "version");
        if (!version)
          continue;
        if (versionChecker.compare(appVersion, version) == 0)
          this._parseVersionData(aDataSource, update, this._service._currentVersion);
        else if (versionChecker.compare(newestVersionObj.version, version) < 0) {
          newestVersionObj.version = version;
          newestVersionObj.resource = update;
        }
      }
      if (newestVersionObj.resource)
        this._parseVersionData(aDataSource, newestVersionObj.resource, this._service._newestVersion);
      
      // There is a newer version of the app available or there are any critical
      // patches available update the severity and available updates preferences.
      // XXXben also note if there are langpacks available that match the user's
      //        preference if they previously installed an app update when a 
      //        langpack for their language was not available and they used another
      //        in the meantime. 
      var haveLanguage = false;
      var patches = this._service._currentVersion.patches;
      var languages = this._service._newestVersion.languages;
      if (languages) {
        var cr = Components.classes["@mozilla.org/chrome/chrome-registry;1"]
                           .getService(Components.interfaces.nsIXULChromeRegistry);
        var selectedLocale = cr.getSelectedLocale("global");
        for (var i = 0; i < languages.length; ++i) {
          if (languages[i].internalName == selectedLocale)
            haveLanguage = true;
        }
      }
      
      if ((haveLanguage && (newestVersionObj.version != appVersion)) || 
          (patches && patches.length > 0)) {
        gPref.setIntPref(PREF_UPDATE_SEVERITY, 2);
        gPref.setBoolPref(PREF_UPDATE_APP_UPDATESAVAILABLE, true);
      }
      else
        gPref.setBoolPref(PREF_UPDATE_APP_UPDATESAVAILABLE, false);

      if (!gPref.getBoolPref(PREF_UPDATE_APP_UPDATESAVAILABLE)) {
        this._service._clearAppUpdatePrefs();

        // Lower the severity to reflect the fact that there are now only Extension/
        // Theme updates available
        var newCount = gPref.getIntPref(PREF_UPDATE_EXTENSIONS_COUNT);
        var threshold = gPref.getIntPref(PREF_UPDATE_EXTENSIONS_SEVERITY_THRESHOLD);
        if (newCount >= threshold)
          gPref.setIntPref(PREF_UPDATE_SEVERITY, nsIUpdateService.SEVERITY_MEDIUM);
        else
          gPref.setIntPref(PREF_UPDATE_SEVERITY, nsIUpdateService.SEVERITY_LOW);
      }
    }

    // The Update Wizard uses this notification to determine that the application
    // update process is now complete. 
    gOS.notifyObservers(null, "Update:App:Ended", "");
  },
  
  _parseVersionData: function nsAppUpdater__parseVersionData (aDataSource, 
                                                              aUpdateResource, 
                                                              aTargetObj)
  {
    aTargetObj.updateVersion          = this._getPropertyFromResource(aDataSource, aUpdateResource, "version");
    aTargetObj.updateDisplayVersion   = this._getPropertyFromResource(aDataSource, aUpdateResource, "displayVersion");
    if (!aTargetObj.updateDisplayVersion)
      aTargetObj.updateDisplayVersion = this._getPropertyFromResource(aDataSource, aUpdateResource, "version");
    aTargetObj.updateInfoURL          = this._getPropertyFromResource(aDataSource, aUpdateResource, "infoURL");
    
    aTargetObj.features   = this._parseUpdateCollection(aDataSource, aUpdateResource, "features");
    aTargetObj.files      = this._parseUpdateCollection(aDataSource, aUpdateResource, "files");
    aTargetObj.optional   = this._parseUpdateCollection(aDataSource, aUpdateResource, "optional");
    aTargetObj.languages  = this._parseUpdateCollection(aDataSource, aUpdateResource, "languages");
    aTargetObj.patches    = this._parseUpdateCollection(aDataSource, aUpdateResource, "patches");
  },
  
  _parseUpdateCollection: function nsAppUpdater__parseUpdateCollection (aDataSource, 
                                                                        aUpdateResource, 
                                                                        aCollectionName)
  {
    if (!aUpdateResource)
      return null;
  
    var result = [];
    
    var collectionArc = gRDF.GetResource(APP_NS(aCollectionName));
    var collectionResource = aDataSource.GetTarget(aUpdateResource, collectionArc, true);
    
    try {
      collectionResource = collectionResource.QueryInterface(Components.interfaces.nsIRDFResource);
    }
    catch (e) { return null; }
    
    var cu = Components.classes["@mozilla.org/rdf/container-utils;1"]
                       .getService(Components.interfaces.nsIRDFContainerUtils);
    if (cu.IsContainer(aDataSource, collectionResource)) {
      var c = Components.classes["@mozilla.org/rdf/container;1"]
                        .getService(Components.interfaces.nsIRDFContainer);
      c.Init(aDataSource, collectionResource);
      
      var elements = c.GetElements();
      var fileArc = gRDF.GetResource(APP_NS("file"));
      var platform = getOSKey();
      while (elements.hasMoreElements()) {
        var element = elements.getNext().QueryInterface(Components.interfaces.nsIRDFResource);
        var info = new nsAppUpdateInfoItem();
        info.name          = this._getPropertyFromResource(aDataSource, element, "name");
        info.internalName  = this._getPropertyFromResource(aDataSource, element, "internalName");
        
        // Each Component has a set of app:file arcs out, which reference resources with two 
        // properties: app:platform and app:URL. If we find a resource whose app:platform value
        // matches the platform we're running on, we use the app:URL property on that resource
        // as the XPI URL, otherwise we use the default app:URL property on the Component
        // resource. (It must be a cross-platform piece, e.g. a language pack)
        // XXXben - what to do when platform not supported? We need some way to abort 
        //          and tell the app that this update is not available. 
        var files = aDataSource.GetTargets(element, fileArc, true);
        while (files.hasMoreElements()) {
          var file = files.getNext().QueryInterface(Components.interfaces.nsIRDFResource);
          if (platform == this._getPropertyFromResource(aDataSource, file, "platform")) {
            info.URL = this._getPropertyFromResource(aDataSource, file, "URL");
            break;
          }
        }
        if (!info.URL)
          info.URL         = this._getPropertyFromResource(aDataSource, element, "URL");
        info.infoURL       = this._getPropertyFromResource(aDataSource, element, "infoURL");
        info.description   = this._getPropertyFromResource(aDataSource, element, "description");
        result.push(info);
      }
    }

    return result;
  },
  
  onDatasourceError: function (aStatus, aErrorMsg)
  {
    gOS.notifyObservers(null, "Update:App:Error", "");
    gOS.notifyObservers(null, "Update:App:Ended", "");
  },
  
  /////////////////////////////////////////////////////////////////////////////
  // nsIRDFXMLSinkObserver
  onBeginLoad: function(aSink)
  {
  },
  onInterrupt: function(aSink)
  {
  },
  onResume: function(aSink)
  {
  },
  
  onEndLoad: function(aSink)
  {
    try {
      this._ds = aSink.QueryInterface(Components.interfaces.nsIRDFDataSource);
      this.onDatasourceLoaded(this._ds);
    }
    catch (e) { }
  },
  
  onError: function(aSink, aStatus, aErrorMsg)
  {
    try {
      this._ds = aSink.QueryInterface(Components.interfaces.nsIRDFDataSource);
      this.onDatasourceError(aStatus, aErrorMsg);
    }
    catch (e) { }
  },

  /////////////////////////////////////////////////////////////////////////////
  // nsISupports
  QueryInterface: function nsAppUpdater_QueryInterface (aIID) 
  {
    if (!aIID.equals(Components.interfaces.nsIRDFXMLSinkObserver) &&
        !aIID.equals(Components.interfaces.nsISupports))
      throw Components.results.NS_ERROR_NO_INTERFACE;
    return this;
  }
}

function UpdateItem ()
{
}

UpdateItem.prototype = {
  init: function UpdateItem_init (aID, 
                                  aVersion, 
                                  aMinAppVersion, 
                                  aMaxAppVersion, 
                                  aName, 
                                  aRow, 
                                  aXPIURL, 
                                  aIconURL, 
                                  aUpdateRDF, 
                                  aType)
  {
    this._id            = aID;
    this._version       = aVersion;
    this._minAppVersion = aMinAppVersion;
    this._maxAppVersion = aMaxAppVersion;
    this._name          = aName;
    this._row           = aRow;
    this._xpiURL        = aXPIURL;
    this._iconURL       = aIconURL;
    this._updateRDF     = aUpdateRDF;
    this._type          = aType;
  },
  
  get id()            { return this._id;            },
  get version()       { return this._version;       },
  get minAppVersion() { return this._minAppVersion; },
  get maxAppVersion() { return this._maxAppVersion; },
  get name()          { return this._name;          },
  get row()           { return this._row;           },
  get xpiURL()        { return this._xpiURL;        },
  get iconURL()       { return this._iconURL        },
  get updateRDF()     { return this._updateRDF;     },
  get type()          { return this._type;          },

  get objectSource()
  {
    return { id             : this._id, 
             version        : this._version, 
             minAppVersion  : this._minAppVersion,
             maxAppVersion  : this._maxAppVersion,
             name           : this._name, 
             row            : this._row, 
             xpiURL         : this._xpiURL, 
             iconURL        : this._iconURL, 
             updateRDF      : this._updateRDF,
             type           : this._type 
           }.toSource();
  },

  /////////////////////////////////////////////////////////////////////////////
  // nsISupports
  QueryInterface: function UpdateItem_QueryInterface (aIID) 
  {
    if (!aIID.equals(Components.interfaces.nsIUpdateItem) &&
        !aIID.equals(Components.interfaces.nsISupports))
      throw Components.results.NS_ERROR_NO_INTERFACE;
    return this;
  }
};

function nsAppUpdateInfoItem ()
{
}
nsAppUpdateInfoItem.prototype = {
  internalName: "",
  name        : "",
  URL         : "",
  infoURL     : "",

  /////////////////////////////////////////////////////////////////////////////
  // nsISupports
  QueryInterface: function nsAppUpdater_QueryInterface (aIID) 
  {
    if (!aIID.equals(Components.interfaces.nsIAppUpdateInfo) &&
        !aIID.equals(Components.interfaces.nsISupports))
      throw Components.results.NS_ERROR_NO_INTERFACE;
    return this;
  }
};

function nsAppUpdateInfo ()
{
}
nsAppUpdateInfo.prototype = {
  updateVersion       : "",
  updateDisplayVersion: "",
  updateInfoURL       : "",

  features  : [],
  files     : [],
  optional  : [],
  languages : [],
  patches   : [], 
  
  getCollection: function (aCollectionName, aItemCount)
  {
    var collection = aCollectionName in this ? this[aCollectionName] : null;
    aItemCount.value = collection ? collection.length : 0;
    return collection;
  },

  /////////////////////////////////////////////////////////////////////////////
  // nsISupports
  QueryInterface: function nsAppUpdater_QueryInterface (aIID) 
  {
    if (!aIID.equals(Components.interfaces.nsIAppUpdateInfoCollection) &&
        !aIID.equals(Components.interfaces.nsISupports))
      throw Components.results.NS_ERROR_NO_INTERFACE;
    return this;
  }
};

function Version(aMajor, aMinor, aRelease, aBuild, aPlus) 
{ 
  this.major    = aMajor    || 0;
  this.minor    = aMinor    || 0;
  this.release  = aRelease  || 0;
  this.build    = aBuild    || 0;
  this.plus     = aPlus     || 0;
}

Version.prototype = {
  toString: function Version_toString() 
  {
    return this.major + "." + this.minor + "." + this.subminor + "." + this.release + (this.plus ? "+" : "");
  },
  
  compare: function (aVersion)
  {
    var fields = ["major", "minor", "release", "build", "plus"];
    
    for (var i = 0; i < fields.length; ++i) {
      var field = fields[i];
      if (aVersion[field] > this[field])
        return -1;
      else if (aVersion[field] < this[field])
        return 1;
    }
    return 0;
  }
}

function nsVersionChecker()
{
}

nsVersionChecker.prototype = {
  /////////////////////////////////////////////////////////////////////////////
  // nsIVersionChecker
  
  // -ve      if B is newer
  // equal    if A == B
  // +ve      if A is newer
  compare: function nsVersionChecker_compare (aVersionA, aVersionB)
  {
    var a = this._decomposeVersion(aVersionA);
    var b = this._decomposeVersion(aVersionB);
    
    return a.compare(b);
  },
  
  _decomposeVersion: function nsVersionChecker__decomposeVersion (aVersion)
  {
    var plus = 0;
    if (aVersion.charAt(aVersion.length-1) == "+") {
      aVersion = aVersion.substr(0, aVersion.length-1);
      plus = 1;
    }

    var parts = aVersion.split(".");
    
    return new Version(this._getValidInt(parts[0]),
                       this._getValidInt(parts[1]),
                       this._getValidInt(parts[2]),
                       this._getValidInt(parts[3]),
                       plus);
  },
  
  _getValidInt: function nsVersionChecker__getValidInt (aPartString)
  {
    var integer = parseInt(aPartString);
    if (isNaN(integer))
      return 0;
    return integer;
  },
  
  isValidVersion: function nsVersionChecker_isValidVersion (aVersion)
  {
    var parts = aVersion.split(".");
    if (parts.length == 0)
      return false;
    for (var i = 0; i < parts.length; ++i) {
      var part = parts[i];
      if (i == parts.length - 1) {
        if (part.lastIndexOf("+") != -1) 
          parts[i] = part.substr(0, part.length - 1);
      }
      var integer = parseInt(part);
      if (isNaN(integer))
        return false;
    }
    return true;
  },

  /////////////////////////////////////////////////////////////////////////////
  // nsISupports
  QueryInterface: function nsVersionChecker_QueryInterface (aIID) 
  {
    if (!aIID.equals(Components.interfaces.nsIVersionChecker) &&
        !aIID.equals(Components.interfaces.nsISupports))
      throw Components.results.NS_ERROR_NO_INTERFACE;
    return this;
  }
};

var gModule = {
  _firstTime: true,
  
  registerSelf: function (aComponentManager, aFileSpec, aLocation, aType) 
  {
    if (this._firstTime) {
      this._firstTime = false;
      throw Components.results.NS_ERROR_FACTORY_REGISTER_AGAIN;
    }
    aComponentManager = aComponentManager.QueryInterface(Components.interfaces.nsIComponentRegistrar);
    
    for (var key in this._objects) {
      var obj = this._objects[key];
      aComponentManager.registerFactoryLocation(obj.CID, obj.className, obj.contractID,
                                                aFileSpec, aLocation, aType);
    }
  },
  
  getClassObject: function (aComponentManager, aCID, aIID) 
  {
    if (!aIID.equals(Components.interfaces.nsIFactory))
      throw Components.results.NS_ERROR_NOT_IMPLEMENTED;

    for (var key in this._objects) {
      if (aCID.equals(this._objects[key].CID))
        return this._objects[key].factory;
    }
    
    throw Components.results.NS_ERROR_NO_INTERFACE;
  },
  
  _objects: {
    manager: { CID: Components.ID("{B3C290A6-3943-4B89-8BBE-C01EB7B3B311}"),
               contractID: "@mozilla.org/updates/update-service;1",
               className: "Update Service",
               factory: {
                          createInstance: function (aOuter, aIID) 
                          {
                            if (aOuter != null)
                              throw Components.results.NS_ERROR_NO_AGGREGATION;
                            
                            return (new nsUpdateService()).QueryInterface(aIID);
                          }
                        }
             },
    version: { CID: Components.ID("{9408E0A5-509E-45E7-80C1-0F35B99FF7A9}"),
               contractID: "@mozilla.org/updates/version-checker;1",
               className: "Version Checker",
               factory: {
                          createInstance: function (aOuter, aIID) 
                          {
                            if (aOuter != null)
                              throw Components.results.NS_ERROR_NO_AGGREGATION;
                            
                            return (new nsVersionChecker()).QueryInterface(aIID);
                          }
                        }
             },
    item:    { CID: Components.ID("{F3294B1C-89F4-46F8-98A0-44E1EAE92518}"),
               contractID: "@mozilla.org/updates/item;1",
               className: "Extension Item",
               factory: {
                          createInstance: function (aOuter, aIID) 
                          {
                            if (aOuter != null)
                              throw Components.results.NS_ERROR_NO_AGGREGATION;
                            
                            return new UpdateItem().QueryInterface(aIID);
                          }
                        } 
             }  
   },
  
  canUnload: function (aComponentManager) 
  {
    return true;
  }
};

function NSGetModule(compMgr, fileSpec) 
{
  return gModule;
}

