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/* 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/. */
Cu.import("resource://gre/modules/Services.jsm");
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
exports.WindowObserver = WindowObserver;
/**
* This class will call listener's method applyToWindow() for all new chrome
* windows being opened. It will also call listener's method removeFromWindow()
* for all windows still open when the extension is shut down.
* @param {Object} listener
* @param {String} [when] when to execute applyToWindow(). "start" means immediately
* when the window opens, "ready" when its contents are available
* and "end" (default) means to wait until the "load" event.
* @constructor
*/
function WindowObserver(listener, when)
{
this._listener = listener;
this._when = when;
let windows = [];
let e = Services.wm.getZOrderDOMWindowEnumerator(null, true);
while (e.hasMoreElements())
windows.push(e.getNext());
// Check if there are any windows that we missed
let eAll = Services.ww.getWindowEnumerator();
while (eAll.hasMoreElements())
{
let element = eAll.getNext();
if (windows.indexOf(element) < 0)
windows.push(element);
}
for (let i = 0; i < windows.length; i++)
{
let window = windows[i].QueryInterface(Ci.nsIDOMWindow);
if (when == "start" || window.document.readyState == "complete")
this._listener.applyToWindow(window);
else
this.observe(window, "chrome-document-global-created", null);
}
Services.obs.addObserver(this, "chrome-document-global-created", true);
this._shutdownHandler = function()
{
let e = Services.ww.getWindowEnumerator();
while (e.hasMoreElements())
this._listener.removeFromWindow(e.getNext().QueryInterface(Ci.nsIDOMWindow));
Services.obs.removeObserver(this, "chrome-document-global-created");
}.bind(this);
onShutdown.add(this._shutdownHandler);
}
WindowObserver.prototype =
{
_listener: null,
_when: null,
_shutdownHandler: null,
shutdown: function()
{
if (!this._shutdownHandler)
return;
onShutdown.remove(this._shutdownHandler);
this._shutdownHandler();
this._shutdownHandler = null;
},
observe: function(subject, topic, data)
{
if (topic == "chrome-document-global-created")
{
let window = subject.QueryInterface(Ci.nsIDOMWindow);
if (this._when == "start")
{
this._listener.applyToWindow(window);
return;
}
let event = (this._when == "ready" ? "DOMContentLoaded" : "load");
let listener = function()
{
window.removeEventListener(event, listener, false);
if (this._shutdownHandler)
this._listener.applyToWindow(window);
}.bind(this);
window.addEventListener(event, listener, false);
}
},
QueryInterface: XPCOMUtils.generateQI([Ci.nsISupportsWeakReference, Ci.nsIObserver])
};
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