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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/. */
'use strict';
module.metadata = {
"stability": "unstable"
};
const { EventTarget } = require("../event/target");
const { emit } = require("../event/core");
const { DOMEventAssembler } = require("../deprecated/events/assembler");
const { Class } = require("../core/heritage");
const { getActiveTab, getTabs } = require("./utils");
const { browserWindowIterator } = require("../deprecated/window-utils");
const { isBrowser, windows, getMostRecentBrowserWindow } = require("../window/utils");
const { observer: windowObserver } = require("../windows/observer");
const { when } = require("../system/unload");
const EVENTS = {
"TabOpen": "open",
"TabClose": "close",
"TabSelect": "select",
"TabMove": "move",
"TabPinned": "pinned",
"TabUnpinned": "unpinned"
};
const selectedTab = Symbol("observer/state/selectedTab");
// Event emitter objects used to register listeners and emit events on them
// when they occur.
const Observer = Class({
implements: [EventTarget, DOMEventAssembler],
initialize() {
this[selectedTab] = null;
// Currently Gecko does not dispatch any event on the previously selected
// tab before / after "TabSelect" is dispatched. In order to work around this
// limitation we keep track of selected tab and emit "deactivate" event with
// that before emitting "activate" on selected tab.
this.on("select", tab => {
const selected = this[selectedTab];
if (selected !== tab) {
if (selected) {
emit(this, 'deactivate', selected);
}
if (tab) {
this[selectedTab] = tab;
emit(this, 'activate', this[selectedTab]);
}
}
});
// We also observe opening / closing windows in order to add / remove it's
// containers to the observed list.
windowObserver.on("open", chromeWindow => {
if (isBrowser(chromeWindow)) {
this.observe(chromeWindow);
}
});
windowObserver.on("close", chromeWindow => {
if (isBrowser(chromeWindow)) {
// Bug 751546: Emit `deactivate` event on window close immediatly
// Otherwise we are going to face "dead object" exception on `select` event
if (getActiveTab(chromeWindow) === this[selectedTab]) {
emit(this, "deactivate", this[selectedTab]);
this[selectedTab] = null;
}
this.ignore(chromeWindow);
}
});
// Currently gecko does not dispatches "TabSelect" events when different
// window gets activated. To work around this limitation we emulate "select"
// event for this case.
windowObserver.on("activate", chromeWindow => {
if (isBrowser(chromeWindow)) {
emit(this, "select", getActiveTab(chromeWindow));
}
});
// We should synchronize state, since probably we already have at least one
// window open.
for (let chromeWindow of browserWindowIterator()) {
this.observe(chromeWindow);
}
when(_ => {
// Don't dispatch a deactivate event during unload.
this[selectedTab] = null;
});
},
/**
* Events that are supported and emitted by the module.
*/
supportedEventsTypes: Object.keys(EVENTS),
/**
* Function handles all the supported events on all the windows that are
* observed. Method is used to proxy events to the listeners registered on
* this event emitter.
* @param {Event} event
* Keyboard event being emitted.
*/
handleEvent: function handleEvent(event) {
emit(this, EVENTS[event.type], event.target, event);
}
});
exports.observer = new Observer();
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