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mirror of https://github.com/kkapsner/CanvasBlocker synced 2024-10-31 18:38:45 +01:00
CanvasBlocker/lib/modifiedSVGAPI.js
2022-02-13 14:57:36 +01:00

88 lines
2.3 KiB
JavaScript

/* 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/. */
(function(){
"use strict";
let scope;
if ((typeof exports) !== "undefined"){
scope = exports;
}
else {
scope = require.register("./modifiedSVGAPI", {});
}
const {checkerWrapper, setProperties, getStatusByFlag} = require("./modifiedAPIFunctions");
const {byteArrayToString: hash} = require("./hash");
let randomSupply = null;
scope.setRandomSupply = function(supply){
randomSupply = supply;
};
function getValueHash(value){
return hash(new Float32Array([value]));
}
const cache = {};
function getFakeValue(value, window){
const valueHash = getValueHash(value);
let cachedValue = cache[valueHash];
if (typeof cachedValue === "number"){
return cachedValue;
}
else {
const rng = randomSupply.getRng(1, window);
const fakedValue = value + 0.01 * (rng(0) / 0xffffffff - 0.5);
const fakedHash = getValueHash(fakedValue);
cache[valueHash] = fakedValue;
cache[fakedHash] = fakedValue;
return fakedValue;
}
}
scope.getFakeValue = getFakeValue;
function getFakeValueCallback(args, check){
const {notify, window, original} = check;
const ret = args.length? original.call(this, ...args): original.call(this);
notify("fakedSVGReadout");
return getFakeValue(ret, window);
}
scope.changedFunctions = {
getTotalLength: {
object: ["SVGGeometryElement"],
fakeGenerator: function(checker){
return function getTotalLength(){
return checkerWrapper(checker, this, arguments, getFakeValueCallback);
};
}
},
getComputedTextLength: {
object: ["SVGTextContentElement"],
fakeGenerator: function(checker){
return function getComputedTextLength(){
return checkerWrapper(checker, this, arguments, getFakeValueCallback);
};
}
},
getSubStringLength: {
object: ["SVGTextContentElement"],
fakeGenerator: function(checker){
return function getSubStringLength(charnum, nchars){
return checkerWrapper(checker, this, arguments, getFakeValueCallback);
};
}
},
};
scope.changedGetters = [];
setProperties(scope.changedFunctions, scope.changedGetters, {
type: "readout",
getStatus: getStatusByFlag("protectSVG"),
api: "svg"
});
}());