96 lines
3.3 KiB
JavaScript
96 lines
3.3 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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(function(){
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"use strict";
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let scope;
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if ((typeof exports) !== "undefined"){
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scope = exports;
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}
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else {
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scope = require.register("./modifiedTextMetricsAPI", {});
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}
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const {checkerWrapper, setProperties, getStatusByFlag} = require("./modifiedAPIFunctions");
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const {byteArrayToString: hash} = require("./hash");
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const {cache} = require("./modifiedDOMRectAPI");
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const valueCache = cache.valueCache;
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function getValueHash(value){
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return hash(new Float32Array([value]));
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}
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let randomSupply = null;
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scope.setRandomSupply = function(supply){
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randomSupply = supply;
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};
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function getFakeValue(window, value, i, prefs){
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const valueHash = getValueHash(value);
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const cache = valueCache[i];
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let cachedValue = cache[valueHash];
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if (typeof cachedValue === "number"){
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return cachedValue;
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}
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if ((value * prefs("domRectIntegerFactor", window.location)) % 1 === 0){
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cache[valueHash] = value;
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return value;
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}
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else {
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const rng = randomSupply.getRng(5, window);
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const fakedValue = value + 0.01 * (rng(i) / 0xffffffff - 0.5);
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const fakedHash = getValueHash(fakedValue);
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cache[valueHash] = fakedValue;
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cache[fakedHash] = fakedValue;
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return fakedValue;
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}
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}
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function generateChangedTextMetricsPropertyGetter(property, cacheIndex){
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const changedGetter = {
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objectGetters: [
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function(window){return window.TextMetrics && window.TextMetrics.prototype;}
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],
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name: property,
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getterGenerator: function(checker){
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const temp = {
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get [property](){
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return checkerWrapper(checker, this, arguments, function(args, check){
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const {prefs, notify, window, original} = check;
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const originalValue = original.call(this, ...args);
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const returnValue = getFakeValue(window, originalValue, cacheIndex, prefs);
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if (originalValue !== returnValue){
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notify("fakedTextMetricsReadout");
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}
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return returnValue;
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});
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}
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};
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return Object.getOwnPropertyDescriptor(temp, property).get;
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}
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};
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return changedGetter;
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}
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scope.changedGetters = [
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generateChangedTextMetricsPropertyGetter("width", cache.WIDTH),
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generateChangedTextMetricsPropertyGetter("actualBoundingBoxAscent", cache.OTHER),
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generateChangedTextMetricsPropertyGetter("actualBoundingBoxDescent", cache.OTHER),
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generateChangedTextMetricsPropertyGetter("actualBoundingBoxLeft", cache.OTHER),
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generateChangedTextMetricsPropertyGetter("actualBoundingBoxRight", cache.OTHER),
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generateChangedTextMetricsPropertyGetter("alphabeticBaseline", cache.OTHER),
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generateChangedTextMetricsPropertyGetter("emHeightAscent", cache.OTHER),
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generateChangedTextMetricsPropertyGetter("emHeightDescent", cache.OTHER),
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generateChangedTextMetricsPropertyGetter("fontBoundingBoxAscent", cache.OTHER),
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generateChangedTextMetricsPropertyGetter("fontBoundingBoxDescent", cache.OTHER),
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generateChangedTextMetricsPropertyGetter("hangingBaseline", cache.OTHER),
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generateChangedTextMetricsPropertyGetter("ideographicBaseline", cache.OTHER),
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];
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setProperties({}, scope.changedGetters, {
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type: "readout",
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getStatus: getStatusByFlag("protectTextMetrics"),
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api: "textMetrics"
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});
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}()); |