gecko-dev/devtools/shared/content-observer.js

72 lines
2.2 KiB
JavaScript

/* 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/. */
"use strict";
const {Ci} = require("chrome");
const Services = require("Services");
const events = require("sdk/event/core");
/**
* Handles adding an observer for the creation of content document globals,
* event sent immediately after a web content document window has been set up,
* but before any script code has been executed.
*/
function ContentObserver(tabActor) {
this._contentWindow = tabActor.window;
this._onContentGlobalCreated = this._onContentGlobalCreated.bind(this);
this._onInnerWindowDestroyed = this._onInnerWindowDestroyed.bind(this);
this.startListening();
}
module.exports.ContentObserver = ContentObserver;
ContentObserver.prototype = {
/**
* Starts listening for the required observer messages.
*/
startListening: function () {
Services.obs.addObserver(
this._onContentGlobalCreated, "content-document-global-created", false);
Services.obs.addObserver(
this._onInnerWindowDestroyed, "inner-window-destroyed", false);
},
/**
* Stops listening for the required observer messages.
*/
stopListening: function () {
Services.obs.removeObserver(
this._onContentGlobalCreated, "content-document-global-created");
Services.obs.removeObserver(
this._onInnerWindowDestroyed, "inner-window-destroyed");
},
/**
* Fired immediately after a web content document window has been set up.
*/
_onContentGlobalCreated: function (subject, topic, data) {
if (subject == this._contentWindow) {
events.emit(this, "global-created", subject);
}
},
/**
* Fired when an inner window is removed from the backward/forward cache.
*/
_onInnerWindowDestroyed: function (subject, topic, data) {
let id = subject.QueryInterface(Ci.nsISupportsPRUint64).data;
events.emit(this, "global-destroyed", id);
}
};
// Utility functions.
ContentObserver.GetInnerWindowID = function (window) {
return window
.QueryInterface(Ci.nsIInterfaceRequestor)
.getInterface(Ci.nsIDOMWindowUtils)
.currentInnerWindowID;
};