chrome/browser/resources/sync_internals/sync_log.js

// Copyright (c) 2011 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.

// require: cr.js
// require: cr/event_target.js

/**
 * @fileoverview This creates a log object which listens to and
 * records all sync events.
 */

cr.define('chrome.sync', function() {
  /**
   * Creates a new log object which then immediately starts recording
   * sync events.  Recorded entries are available in the 'entries'
   * property and there is an 'append' event which can be listened to.
   * @constructor
   * @extends {cr.EventTarget}
   */
  var Log = function() {
    var self = this;

    var makeListener = function(service, event) {
      return function(details) {
        self.log_(service, event, details);
      };
    };

    for (var eventType in chrome.sync.events) {
      var events = chrome.sync.events[eventType];
      for (var i = 0; i < events.length; ++i) {
        var eventName = events[i];
        var event = chrome.sync[eventName];
        event.addListener(makeListener(eventType, eventName));
      }
    }
  };

  Log.prototype = {
    __proto__: cr.EventTarget.prototype,

    /**
     * The recorded log entries.
     * @type {array}
     */
    entries: [],

    /**
     * Records a single event with the given parameters and fires the
     * 'append' event with the newly-created event as the 'detail'
     * field of a custom event.
     * @param {string} submodule The sync submodule for the event.
     * @param {string} event The name of the event.
     * @param {dictionary} details A dictionary of event-specific details.
     */
    log_: function(submodule, event, details) {
      var entry = {
        submodule: submodule,
        event: event,
        date: new Date(),
        details: details
      };
      this.entries.push(entry);
      // Fire append event.
      var e = cr.doc.createEvent('CustomEvent');
      e.initCustomEvent('append', false, false, entry);
      this.dispatchEvent(e);
    }
  };

  return {
    log: new Log()
  };
});