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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";
loader.lazyRequireGetter(
this,
["loadSheet", "removeSheet"],
true
);
// Highlighter style used for preventing transitions and applying transparency
// when calculating colour contrast.
const HIGHLIGHTER_STYLES_SHEET = `data:text/css;charset=utf-8,
* {
transition: initial !important;
}
:-moz-devtools-highlighted {
color: transparent !important;
text-shadow: none !important;
}`;
/**
* Helper function that determines if nsIAccessible object is in defunct state.
*
* @param {nsIAccessible} accessible
* object to be tested.
* @return {Boolean}
* True if accessible object is defunct, false otherwise.
*/
function isDefunct(accessible) {
// If accessibility is disabled, safely assume that the accessible object is
// now dead.
if (!Services.appinfo.accessibilityEnabled) {
return true;
}
let defunct = false;
try {
const extraState = {};
accessible.getState({}, extraState);
// extraState.value is a bitmask. We are applying bitwise AND to mask out
// irrelevant states.
defunct = !!(extraState.value & Ci.nsIAccessibleStates.EXT_STATE_DEFUNCT);
} catch (e) {
defunct = true;
}
return defunct;
}
/**
* Load highlighter style sheet used for preventing transitions and
* applying transparency when calculating colour contrast.
*
* @param {Window} win
* Window where highlighting happens.
*/
function loadSheetForBackgroundCalculation(win) {
loadSheet(win, HIGHLIGHTER_STYLES_SHEET);
}
/**
* Unload highlighter style sheet used for preventing transitions
* and applying transparency when calculating colour contrast.
*
* @param {Window} win
* Window where highlighting was happenning.
*/
function removeSheetForBackgroundCalculation(win) {
removeSheet(win, HIGHLIGHTER_STYLES_SHEET);
}
/**
* Get role attribute for an accessible object if specified for its
* corresponding DOMNode.
*
* @param {nsIAccessible} accessible
* Accessible for which to determine its role attribute value.
*
* @returns {null|String}
* Role attribute value if specified.
*/
function getAriaRoles(accessible) {
try {
return accessible.attributes.getStringProperty("xml-roles");
} catch (e) {
// No xml-roles. nsPersistentProperties throws if the attribute for a key
// is not found.
}
return null;
}
exports.getAriaRoles = getAriaRoles;
exports.isDefunct = isDefunct;
exports.loadSheetForBackgroundCalculation = loadSheetForBackgroundCalculation;
exports.removeSheetForBackgroundCalculation =
removeSheetForBackgroundCalculation;