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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
"use strict";
const {
accessibilitySpec,
loader.lazyRequireGetter(
this,
"AccessibleWalkerActor",
true
);
loader.lazyRequireGetter(
this,
"SimulatorActor",
true
);
/**
* The AccessibilityActor is a top level container actor that initializes
* accessible walker and is the top-most point of interaction for accessibility
* tools UI for a top level content process.
*/
class AccessibilityActor extends Actor {
constructor(conn, targetActor) {
super(conn, accessibilitySpec);
// This event is fired when accessibility service is initialized or shut
// down. "init" and "shutdown" events are only relayed when the enabled
// state matches the event (e.g. the event came from the same process as
// the actor).
Services.obs.addObserver(this, "a11y-init-or-shutdown");
this.targetActor = targetActor;
}
getTraits() {
// The traits are used to know if accessibility actors support particular
// API on the server side.
return {
tabbingOrder: true,
};
}
bootstrap() {
return {
enabled: this.enabled,
};
}
get enabled() {
return Services.appinfo.accessibilityEnabled;
}
/**
* Observe Accessibility service init and shutdown events. It relays these
* events to AccessibilityFront if the event is fired for the a11y service
* that lives in the same process.
*
* @param {null} subject
* Not used.
* @param {String} topic
* Name of the a11y service event: "a11y-init-or-shutdown".
* @param {String} data
* "0" corresponds to shutdown and "1" to init.
*/
observe(subject, topic, data) {
const enabled = data === "1";
if (enabled && this.enabled) {
this.emit("init");
} else if (!enabled && !this.enabled) {
if (this.walker) {
this.walker.reset();
}
this.emit("shutdown");
}
}
/**
* Get or create AccessibilityWalker actor, similar to WalkerActor.
*
* @return {Object}
* AccessibleWalkerActor for the current tab.
*/
getWalker() {
if (!this.walker) {
this.walker = new AccessibleWalkerActor(this.conn, this.targetActor);
this.manage(this.walker);
}
return this.walker;
}
/**
* Get or create Simulator actor, managed by AccessibilityActor,
* only if webrender is enabled. Simulator applies color filters on an entire
* viewport. This needs to be done using webrender and not an SVG
* <feColorMatrix> since it is accelerated and scrolling with filter applied
*
* @return {Object|null}
* SimulatorActor for the current tab.
*/
getSimulator() {
if (!this.simulator) {
this.simulator = new SimulatorActor(this.conn, this.targetActor);
this.manage(this.simulator);
}
return this.simulator;
}
/**
* Destroy accessibility actor. This method also shutsdown accessibility
* service if possible.
*/
async destroy() {
super.destroy();
Services.obs.removeObserver(this, "a11y-init-or-shutdown");
this.walker = null;
this.targetActor = null;
}
}
exports.AccessibilityActor = AccessibilityActor;