gecko/services/sync/modules/trackers.js

/* ***** 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 Bookmarks Sync.
 *
 * The Initial Developer of the Original Code is Mozilla.
 * Portions created by the Initial Developer are Copyright (C) 2007
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *  Anant Narayanan <anant@kix.in>
 *
 * 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 EXPORTED_SYMBOLS = ['Tracker', 'BookmarksTracker', 'HistoryTracker',
                          'FormsTracker'];

const Cc = Components.classes;
const Ci = Components.interfaces;
const Cr = Components.results;
const Cu = Components.utils;

Cu.import("resource://gre/modules/XPCOMUtils.jsm");
Cu.import("resource://weave/log4moz.js");
Cu.import("resource://weave/constants.js");
Cu.import("resource://weave/util.js");
Cu.import("resource://weave/async.js");

Function.prototype.async = Async.sugar;

/*
 * Trackers are associated with a single engine and deal with
 * listening for changes to their particular data type
 * and updating their 'score', indicating how urgently they
 * want to sync.
 * 
 * 'score's range from 0 (Nothing's changed)
 * to 100 (I need to sync now!)
 * -1 is also a valid score
 * (don't sync me unless the user specifically requests it)
 *
 * Setting a score outside of this range will raise an exception.
 * Well not yet, but it will :)
 */
function Tracker() {
 this._init();
}
Tracker.prototype = {
 _logName: "Tracker",
 _score: 0,

 _init: function T__init() {
   this._log = Log4Moz.Service.getLogger("Service." + this._logName);
   this._score = 0;
 },

 /* Should be called by service periodically
  * before deciding which engines to sync
  */
 get score() {
   if (this._score >= 100)
    return 100;
   else
    return this._score;
 },

 /* Should be called by service everytime a sync
  * has been done for an engine
  */
 resetScore: function T_resetScore() {
   this._score = 0;
 }
};
 
/*
 * Tracker objects for each engine may need to subclass the
 * getScore routine, which returns the current 'score' for that
 * engine. How the engine decides to set the score is upto it,
 * as long as the value between 0 and 100 actually corresponds
 * to its urgency to sync.
 *
 * Here's an example BookmarksTracker. We don't subclass getScore
 * because the observer methods take care of updating _score which
 * getScore returns by default.
 */
function BookmarksTracker() {
  this._init();
}
BookmarksTracker.prototype = {
  _logName: "BMTracker",

  /* We don't care about the first three */
  onBeginUpdateBatch: function BMT_onBeginUpdateBatch() {

  },
  onEndUpdateBatch: function BMT_onEndUpdateBatch() {

  },
  onItemVisited: function BMT_onItemVisited() {

  },
  
  /* Every add or remove is worth 4 points,
   * on the basis that adding or removing 20 bookmarks
   * means its time to sync?
   */
  onItemAdded: function BMT_onEndUpdateBatch() {
    this._score += 4;
  },
  onItemRemoved: function BMT_onItemRemoved() {
    this._score += 4;
  },
  /* Changes are worth 2 points? */
  onItemChanged: function BMT_onItemChanged() {
    this._score += 2;
  },

  _init: function BMT__init() {
    super._init();
    Cc["@mozilla.org/browser/nav-bookmarks-service;1"].
    getService(Ci.nsINavBookmarksService).
    addObserver(this, false);
  }
}
BookmarksTracker.prototype.__proto__ = new Tracker();
  
function HistoryTracker() {
  this._init();
}
HistoryTracker.prototype = {
  _logName: "HistoryTracker",

  /* We don't care about the first four */
  onBeginUpdateBatch: function HT_onBeginUpdateBatch() {

  },
  onEndUpdateBatch: function HT_onEndUpdateBatch() {

  },
  onPageChanged: function HT_onPageChanged() {

  },
  onTitleChanged: function HT_onTitleChanged() {

  },
  
  /* Every add or remove is worth 1 point.
   * Clearing the whole history is worth 50 points,
   * to ensure we're above the cutoff for syncing
   * ASAP.
   */
  onVisit: function HT_onVisit(uri, vid, time, session, referrer, trans) {
    this._score += 1;
  },
  onPageExpired: function HT_onPageExpired(uri, time, entry) {
    this._score += 1;
  },
  onDeleteURI: function HT_onDeleteURI(uri) {
    this._score += 1;
  },
  onClearHistory: function HT_onClearHistory() {
    this._score += 50;
  },

  _init: function HT__init() {
    super._init();
    Cc["@mozilla.org/browser/nav-history-service;1"].
    getService(Ci.nsINavHistoryService).
    addObserver(this, false);
  }
}
HistoryTracker.prototype.__proto__ = new Tracker();

function FormsTracker() {
  this._init();
}
FormsTracker.prototype = {
  _logName: "FormsTracker",

  __formDB: null,
  get _formDB() {
    if (!this.__formDB) {
      var file = Cc["@mozilla.org/file/directory_service;1"].
      getService(Ci.nsIProperties).
      get("ProfD", Ci.nsIFile);
      file.append("formhistory.sqlite");
      var stor = Cc["@mozilla.org/storage/service;1"].
      getService(Ci.mozIStorageService);
      this.__formDB = stor.openDatabase(file);
    }

    return this.__formDB;
  }

  /* nsIFormSubmitObserver is not available in JS.
   * To calculate scores, we instead just count the changes in
   * the database since the last time we were asked.
   *
   * FIXME!: Buggy, because changes in a row doesn't result in
   * an increment of our score. A possible fix is to do a
   * SELECT for each fieldname and compare those instead of the
   * whole row count.
   *
   * Each change is worth 2 points. At some point, we may
   * want to differentiate between search-history rows and other
   * form items, and assign different scores.
   */
  _rowCount: 0,
  get score() {
    var stmnt = this._formDB.createStatement("SELECT COUNT(fieldname) FROM moz_formhistory");
    stmnt.executeStep();
    var count = stmnt.getInt32(0);
    stmnt.reset();

    this._score = abs(this._rowCount - count) * 2;

    if (this._score >= 100)
      return 100;
    else
      return this._score;
  },

  resetScore: function FormsTracker_resetScore() {
    var stmnt = this._formDB.createStatement("SELECT COUNT(fieldname) FROM moz_formhistory");
    stmnt.executeStep();
    this._rowCount = stmnt.getInt32(0);
    stmnt.reset();

    super.resetScore();
  },

  _init: function FormsTracker__init() {
    super._init();

    var stmnt = this._formDB.createStatement("SELECT COUNT(fieldname) FROM moz_formhistory");
    stmnt.executeStep();
    this._rowCount = stmnt.getInt32(0);
    stmnt.reset();
  }
}
FormsTracker.prototype.__proto__ = new Tracker();