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: module.metadata = {
michael@0:   "stability": "unstable"
michael@0: };
michael@0: 
michael@0: const { Ci } = require("chrome");
michael@0: const { observe } = require("../event/chrome");
michael@0: const { open } = require("../event/dom");
michael@0: const { windows } = require("../window/utils");
michael@0: const { filter, merge, map, expand } = require("../event/utils");
michael@0: 
michael@0: // Function registers single shot event listeners for relevant window events
michael@0: // that forward events to exported event stream.
michael@0: function eventsFor(window) {
michael@0:   let interactive = open(window, "DOMContentLoaded", { capture: true });
michael@0:   let complete = open(window, "load", { capture: true });
michael@0:   let states = merge([interactive, complete]);
michael@0:   let changes = filter(states, function({target}) target === window.document);
michael@0:   return map(changes, function({type, target}) {
michael@0:     return { type: type, target: target.defaultView }
michael@0:   });
michael@0: }
michael@0: 
michael@0: // In addition to observing windows that are open we also observe windows
michael@0: // that are already already opened in case they're in process of loading.
michael@0: let opened = windows(null, { includePrivate: true });
michael@0: let currentEvents = merge(opened.map(eventsFor));
michael@0: 
michael@0: // Register system event listeners for top level window open / close.
michael@0: function rename({type, target, data}) {
michael@0:   return { type: rename[type], target: target, data: data }
michael@0: }
michael@0: rename.domwindowopened = "open";
michael@0: rename.domwindowclosed = "close";
michael@0: 
michael@0: let openEvents = map(observe("domwindowopened"), rename);
michael@0: let closeEvents = map(observe("domwindowclosed"), rename);
michael@0: let futureEvents = expand(openEvents, function({target}) eventsFor(target));
michael@0: 
michael@0: let channel = merge([currentEvents, futureEvents,
michael@0:                      openEvents, closeEvents]);
michael@0: exports.events = channel;