michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: "use strict";
michael@0: 
michael@0: const {Cc, Ci, Cu, Cr} = require("chrome");
michael@0: const {Services} = Cu.import("resource://gre/modules/Services.jsm", {});
michael@0: 
michael@0: const events = require("sdk/event/core");
michael@0: const {Promise: promise} = Cu.import("resource://gre/modules/Promise.jsm", {});
michael@0: 
michael@0: /**
michael@0:  * Handles adding an observer for the creation of content document globals,
michael@0:  * event sent immediately after a web content document window has been set up,
michael@0:  * but before any script code has been executed.
michael@0:  */
michael@0: function ContentObserver(tabActor) {
michael@0:   this._contentWindow = tabActor.window;
michael@0:   this._onContentGlobalCreated = this._onContentGlobalCreated.bind(this);
michael@0:   this._onInnerWindowDestroyed = this._onInnerWindowDestroyed.bind(this);
michael@0:   this.startListening();
michael@0: }
michael@0: 
michael@0: module.exports.ContentObserver = ContentObserver;
michael@0: 
michael@0: ContentObserver.prototype = {
michael@0:   /**
michael@0:    * Starts listening for the required observer messages.
michael@0:    */
michael@0:   startListening: function() {
michael@0:     Services.obs.addObserver(
michael@0:       this._onContentGlobalCreated, "content-document-global-created", false);
michael@0:     Services.obs.addObserver(
michael@0:       this._onInnerWindowDestroyed, "inner-window-destroyed", false);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Stops listening for the required observer messages.
michael@0:    */
michael@0:   stopListening: function() {
michael@0:     Services.obs.removeObserver(
michael@0:       this._onContentGlobalCreated, "content-document-global-created", false);
michael@0:     Services.obs.removeObserver(
michael@0:       this._onInnerWindowDestroyed, "inner-window-destroyed", false);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Fired immediately after a web content document window has been set up.
michael@0:    */
michael@0:   _onContentGlobalCreated: function(subject, topic, data) {
michael@0:     if (subject == this._contentWindow) {
michael@0:       events.emit(this, "global-created", subject);
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Fired when an inner window is removed from the backward/forward cache.
michael@0:    */
michael@0:   _onInnerWindowDestroyed: function(subject, topic, data) {
michael@0:     let id = subject.QueryInterface(Ci.nsISupportsPRUint64).data;
michael@0:     events.emit(this, "global-destroyed", id);
michael@0:   }
michael@0: };
michael@0: 
michael@0: // Utility functions.
michael@0: 
michael@0: ContentObserver.GetInnerWindowID = function(window) {
michael@0:   return window
michael@0:     .QueryInterface(Ci.nsIInterfaceRequestor)
michael@0:     .getInterface(Ci.nsIDOMWindowUtils)
michael@0:     .currentInnerWindowID;
michael@0: };