James Teh
a43a8917d1
When the only consumer is ePdfOutput, skip three init tasks that exist solely to support real a11y clients and are unnecessary when we only want to build the accessibility tree for a document being printed: 1. ApplicationAccessible::CreateInitialDocs, which forces creation of accessibles for every existing document. 2. PlatformInit, which starts the platform accessibility APIs. 3. Activation of the accessibility service in every content process. These steps have been moved into a new FullInit function. If a real client subsequently arrives while the service is running only for ePdfOutput, GetOrCreateAccService will need to perform these deferred steps at that point. That promotion path will be added in a subsequent patch. As part of this, the a11y-init-or-shutdown notification has been extended with a third possible value of "pdf" indicating that the engine has started in ePdfOutput-only mode. This is necessary so that observers know the engine has started, but can distinguish this from the full init indicated by "1". Differential Revision: https://phabricator.services.mozilla.com/D299956
131 lines
3.6 KiB
JavaScript
131 lines
3.6 KiB
JavaScript
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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"use strict";
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const { Actor } = require("resource://devtools/shared/protocol.js");
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const {
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accessibilitySpec,
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} = require("resource://devtools/shared/specs/accessibility.js");
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loader.lazyRequireGetter(
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this,
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"AccessibleWalkerActor",
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"resource://devtools/server/actors/accessibility/walker.js",
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true
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);
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loader.lazyRequireGetter(
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this,
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"SimulatorActor",
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"resource://devtools/server/actors/accessibility/simulator.js",
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true
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);
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/**
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* The AccessibilityActor is a top level container actor that initializes
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* accessible walker and is the top-most point of interaction for accessibility
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* tools UI for a top level content process.
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*/
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class AccessibilityActor extends Actor {
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constructor(conn, targetActor) {
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super(conn, accessibilitySpec);
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// This event is fired when accessibility service is initialized or shut
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// down. "init" and "shutdown" events are only relayed when the enabled
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// state matches the event (e.g. the event came from the same process as
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// the actor).
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Services.obs.addObserver(this, "a11y-init-or-shutdown");
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this.targetActor = targetActor;
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}
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getTraits() {
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// The traits are used to know if accessibility actors support particular
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// API on the server side.
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return {
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// @backward-compat { version 84 } Fixed on the server by Bug 1654956.
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tabbingOrder: true,
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};
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}
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bootstrap() {
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return {
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enabled: this.enabled,
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};
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}
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get enabled() {
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return Services.appinfo.accessibilityEnabled;
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}
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/**
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* Observe Accessibility service init and shutdown events. It relays these
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* events to AccessibilityFront if the event is fired for the a11y service
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* that lives in the same process.
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*
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* @param {null} subject
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* Not used.
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* @param {string} topic
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* Name of the a11y service event: "a11y-init-or-shutdown".
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* @param {string} data
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* "0" means shutdown. Anything else means init.
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*/
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observe(subject, topic, data) {
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const enabled = data !== "0";
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if (enabled && this.enabled) {
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this.emit("init");
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} else if (!enabled && !this.enabled) {
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if (this.walker) {
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this.walker.reset();
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}
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this.emit("shutdown");
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}
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}
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/**
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* Get or create AccessibilityWalker actor, similar to WalkerActor.
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*
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* @return {object}
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* AccessibleWalkerActor for the current tab.
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*/
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getWalker() {
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if (!this.walker) {
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this.walker = new AccessibleWalkerActor(this.conn, this.targetActor);
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this.manage(this.walker);
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}
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return this.walker;
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}
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/**
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* Get or create Simulator actor, managed by AccessibilityActor,
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* only if webrender is enabled. Simulator applies color filters on an entire
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* viewport. This needs to be done using webrender and not an SVG
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* <feColorMatrix> since it is accelerated and scrolling with filter applied
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* needs to be smooth (Bug1431466).
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*
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* @return {object | null}
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* SimulatorActor for the current tab.
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*/
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getSimulator() {
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if (!this.simulator) {
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this.simulator = new SimulatorActor(this.conn, this.targetActor);
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this.manage(this.simulator);
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}
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return this.simulator;
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}
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/**
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* Destroy accessibility actor. This method also shutsdown accessibility
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* service if possible.
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*/
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async destroy() {
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super.destroy();
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Services.obs.removeObserver(this, "a11y-init-or-shutdown");
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this.walker = null;
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this.targetActor = null;
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}
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}
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exports.AccessibilityActor = AccessibilityActor;
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