CanvasBlocker/lib/modifiedCanvasAPI.js

676 lines
23 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";
const scope = ((typeof exports) !== "undefined")? exports: require.register("./modifiedCanvasAPI");
const colorStatistics = require("./colorStatistics");
const logging = require("./logging");
const {copyCanvasToWebgl} = require("./webgl");
const {getWrapped, checkerWrapper} = require("./modifiedAPIFunctions");
var randomSupply = null;
function getContext(window, canvas){
return window.HTMLCanvasElement.prototype.getContext.call(canvas, "2d") ||
window.HTMLCanvasElement.prototype.getContext.call(canvas, "webgl") ||
window.HTMLCanvasElement.prototype.getContext.call(canvas, "experimental-webgl") ||
window.HTMLCanvasElement.prototype.getContext.call(canvas, "webgl2") ||
window.HTMLCanvasElement.prototype.getContext.call(canvas, "experimental-webgl2");
}
function getImageData(window, context){
var imageData;
var source;
if ((context.canvas.width || 0) * (context.canvas.height || 0) === 0){
imageData = new (getWrapped(window).ImageData)(0, 0);
source = new (getWrapped(window).ImageData)(0, 0);
}
else if (context instanceof window.CanvasRenderingContext2D){
imageData = window.CanvasRenderingContext2D.prototype.getImageData.call(
context,
0, 0,
context.canvas.width, context.canvas.height
);
source = imageData.data;
}
else {
imageData = new (getWrapped(window).ImageData)(context.canvas.width, context.canvas.height);
source = new Uint8Array(imageData.data.length);
(
context instanceof window.WebGLRenderingContext?
window.WebGLRenderingContext:
window.WebGL2RenderingContext
).prototype.readPixels.call(
context,
0, 0, context.canvas.width, context.canvas.height,
context.RGBA, context.UNSIGNED_BYTE,
source
);
}
return {
imageData,
source
};
}
var canvasCache = Object.create(null);
function getFakeCanvas(window, original, prefs){
try {
if (prefs("useCanvasCache")){
var originalDataURL = original.toDataURL();
var cached = canvasCache[originalDataURL];
if (cached){
return cached;
}
}
// original may not be a canvas -> we must not leak an error
var context = getContext(window, original);
var {imageData, source} = getImageData(window, context);
var desc = imageData.data;
var l = desc.length;
var ignoredColors = {};
var statistic;
if (prefs("ignoreFrequentColors")){
statistic = colorStatistics.compute(source);
ignoredColors = statistic.getMaxColors(prefs("ignoreFrequentColors"));
}
if (prefs("minColors")){
if (!colorStatistics.hasMoreColors(source, prefs("minColors"), statistic)){
return original;
}
}
var rng = randomSupply.getPixelRng(l, window, ignoredColors);
var fakeAlphaChannel = prefs("fakeAlphaChannel");
for (var i = 0; i < l; i += 4){
var [r, g, b, a] = rng(
source[i + 0],
source[i + 1],
source[i + 2],
source[i + 3],
i / 4
);
desc[i + 0] = r;
desc[i + 1] = g;
desc[i + 2] = b;
desc[i + 3] = fakeAlphaChannel? a: source[i + 3];
}
var canvas = original.cloneNode(true);
context = window.HTMLCanvasElement.prototype.getContext.call(canvas, "2d");
context.putImageData(imageData, 0, 0);
if (prefs("useCanvasCache")){
canvasCache[originalDataURL] = canvas;
canvasCache[canvas.toDataURL()] = canvas;
}
return canvas;
}
catch (e){
logging.warning("Error while faking:", e);
return original;
}
}
function randomMixImageData(window, imageData1, imageData2){
var data1 = imageData1.data;
var data2 = imageData2.data;
var l = data1.length;
if (l === data2.length){
var rng = randomSupply.getPixelRng(l, window, {});
for (var i = 0; i < l; i += 4){
const signR = data1[i + 0] > data2[i + 0]? -1: 1;
const signG = data1[i + 1] > data2[i + 1]? -1: 1;
const signB = data1[i + 2] > data2[i + 2]? -1: 1;
const signA = data1[i + 3] > data2[i + 3]? -1: 1;
var [deltaR, deltaG, deltaB, deltaA] = rng(
signR * (data2[i + 0] - data1[i + 0]),
signG * (data2[i + 1] - data1[i + 1]),
signB * (data2[i + 2] - data1[i + 2]),
signA * (data2[i + 3] - data1[i + 3]),
i / 4
);
data2[i + 0] = data1[i + 0] + signR * deltaR;
data2[i + 1] = data1[i + 1] + signG * deltaG;
data2[i + 2] = data1[i + 2] + signB * deltaB;
data2[i + 3] = data1[i + 3] + signA * deltaA;
}
}
return imageData2;
}
function canvasSizeShouldBeFaked(canvas, prefs){
if (canvas){
var size = canvas.height * canvas.width;
var maxSize = prefs("maxFakeSize") || Number.POSITIVE_INFINITY;
var minSize = prefs("minFakeSize") || 0;
return size > minSize && size <= maxSize;
}
else {
return true;
}
}
function getProtectedPartChecker(pref, url){
const protectedPart = pref("protectedCanvasPart", url);
if (protectedPart === "everything"){
return function(){
return true;
};
}
else if (protectedPart === "nothing"){
return function(){
return false;
};
}
else {
return function(parts){
if (Array.isArray(parts)){
return parts.some(function(part){
return part === protectedPart;
});
}
else {
return parts === protectedPart;
}
};
}
}
scope.setRandomSupply = function(supply){
randomSupply = supply;
};
var canvasContextType = new WeakMap();
// changed functions and their fakes
scope.changedFunctions = {
getContext: {
type: "context",
getStatus: function(obj, status, prefs){
if (status.internal){
return {
mode: "allow",
type: status.type,
active: false
};
}
else if (getProtectedPartChecker(prefs, status.url)("input")){
return {
mode: status.mode,
type: status.type,
active: true
};
}
else {
status = Object.create(status);
status.active = false;
return status;
}
},
object: "HTMLCanvasElement",
fakeGenerator: function(checker){
return function(context, contextAttributes){
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
canvasContextType.set(this, context);
return original.apply(this, window.Array.from(args));
});
};
}
},
toDataURL: {
type: "readout",
getStatus: function(obj, status, prefs){
const protectedPartChecker = getProtectedPartChecker(prefs, status.url);
status = Object.create(status);
status.active = protectedPartChecker("readout");
if (!status.active && protectedPartChecker("input")){
var contextType = canvasContextType.get(obj);
status.active = contextType !== "2d";
}
return status;
},
object: "HTMLCanvasElement",
fakeGenerator: function(checker){
return function toDataURL(){
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
if (canvasSizeShouldBeFaked(this, prefs)){
var fakeCanvas = getFakeCanvas(window, this, prefs);
if (fakeCanvas !== this){
notify("fakedReadout");
}
return original.apply(fakeCanvas, window.Array.from(args));
}
else {
return original.apply(this, window.Array.from(args));
}
});
};
}
},
toBlob: {
type: "readout",
getStatus: function(obj, status, prefs){
const protectedPartChecker = getProtectedPartChecker(prefs, status.url);
status = Object.create(status);
status.active = protectedPartChecker("readout");
if (!status.active && protectedPartChecker("input")){
var contextType = canvasContextType.get(obj);
status.active = contextType !== "2d";
}
return status;
},
object: "HTMLCanvasElement",
fakeGenerator: function(checker){
return function toBlob(callback){
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
if (canvasSizeShouldBeFaked(this, prefs)){
var fakeCanvas = getFakeCanvas(window, this, prefs);
if (fakeCanvas !== this){
notify("fakedReadout");
}
return original.apply(fakeCanvas, window.Array.from(args));
}
else {
return original.apply(this, window.Array.from(args));
}
});
};
},
exportOptions: {allowCallbacks: true}
},
mozGetAsFile: {
type: "readout",
getStatus: function(obj, status, prefs){
const protectedPartChecker = getProtectedPartChecker(prefs, status.url);
status = Object.create(status);
status.active = protectedPartChecker("readout");
if (!status.active && protectedPartChecker("input")){
var contextType = canvasContextType.get(obj);
status.active = contextType !== "2d";
}
return status;
},
object: "HTMLCanvasElement",
fakeGenerator: function(checker){
return function mozGetAsFile(callback){
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
if (canvasSizeShouldBeFaked(this, prefs)){
var fakeCanvas = getFakeCanvas(window, this, prefs);
if (fakeCanvas !== this){
notify("fakedReadout");
}
return original.apply(fakeCanvas, window.Array.from(args));
}
else {
return original.apply(this, window.Array.from(args));
}
});
};
}
},
getImageData: {
type: "readout",
getStatus: function(obj, status, prefs){
const protectedPartChecker = getProtectedPartChecker(prefs, status.url);
status = Object.create(status);
status.active = protectedPartChecker("readout");
return status;
},
object: "CanvasRenderingContext2D",
fakeGenerator: function(checker){
return function getImageData(sx, sy, sw, sh){
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
var fakeCanvas;
var context = this;
if (this && this.canvas) {
fakeCanvas = getFakeCanvas(window, this.canvas, prefs);
}
if (fakeCanvas && fakeCanvas !== this.canvas){
notify("fakedReadout");
context = window.HTMLCanvasElement.prototype.getContext.call(
fakeCanvas,
"2d"
);
}
return original.apply(context, window.Array.from(args));
}
else {
return original.apply(this, window.Array.from(args));
}
});
};
}
},
isPointInPath: {
type: "readout",
getStatus: function(obj, status, prefs){
const protectedPartChecker = getProtectedPartChecker(prefs, status.url);
status = Object.create(status);
status.active = protectedPartChecker("readout");
return status;
},
object: "CanvasRenderingContext2D",
fakeGenerator: function(checker){
return function isPointInPath(x, y){
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
var rng = randomSupply.getValueRng(1, window);
var originalValue = original.apply(this, window.Array.from(args));
if ((typeof originalValue) === "boolean"){
notify("fakedReadout");
var index = x + this.width * y;
return original.call(this, rng(x, index), rng(y, index), args[2]);
}
else {
return originalValue;
}
});
};
}
},
isPointInStroke: {
type: "readout",
getStatus: function(obj, status, prefs){
const protectedPartChecker = getProtectedPartChecker(prefs, status.url);
status = Object.create(status);
status.active = protectedPartChecker("readout");
return status;
},
object: "CanvasRenderingContext2D",
fakeGenerator: function(checker){
return function isPointInStroke(x, y){
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
var rng = randomSupply.getValueRng(1, window);
var originalValue = original.apply(this, window.Array.from(args));
if ((typeof originalValue) === "boolean"){
notify("fakedReadout");
if (x instanceof window.Path2D){
let path = x;
x = y;
y = args[2];
let index = x + this.width * y;
return original.call(this, path, rng(x, index), rng(y, index));
}
else {
let index = x + this.width * y;
return original.call(this, rng(x, index), rng(y, index));
}
}
else {
return originalValue;
}
});
};
}
},
fillText: {
type: "input",
getStatus: function(obj, status, prefs){
const protectedPartChecker = getProtectedPartChecker(prefs, status.url);
status = Object.create(status);
status.active = protectedPartChecker("input");
return status;
},
object: "CanvasRenderingContext2D",
fakeGenerator: function(checker){
return function fillText(str, x, y){
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
notify("fakedInput");
var oldImageData;
try {
// "this" is not trustable - it may be not a context
oldImageData = getImageData(window, this).imageData;
}
catch (e){
// nothing to do here
}
// if "this" is not a correct context the next line will throw an error
var ret = original.apply(this, window.Array.from(args));
var newImageData = getImageData(window, this).imageData;
this.putImageData(randomMixImageData(window, oldImageData, newImageData), 0, 0);
return ret;
}
else {
return original.apply(this, window.Array.from(args));
}
});
};
}
},
strokeText: {
type: "input",
getStatus: function(obj, status, prefs){
const protectedPartChecker = getProtectedPartChecker(prefs, status.url);
status = Object.create(status);
status.active = protectedPartChecker("input");
return status;
},
object: "CanvasRenderingContext2D",
fakeGenerator: function(checker){
return function strokeText(str, x, y){
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
notify("fakedInput");
var oldImageData;
try {
// "this" is not trustable - it may be not a context
oldImageData = getImageData(window, this).imageData;
}
catch (e){
// nothing to do here
}
// if "this" is not a correct context the next line will throw an error
var ret = original.apply(this, window.Array.from(args));
var newImageData = getImageData(window, this).imageData;
this.putImageData(randomMixImageData(window, oldImageData, newImageData), 0, 0);
return ret;
}
else {
return original.apply(this, window.Array.from(args));
}
});
};
}
},
readPixels: {
type: "readout",
getStatus: function(obj, status, prefs){
const protectedPartChecker = getProtectedPartChecker(prefs, status.url);
status = Object.create(status);
status.active = protectedPartChecker(["readout", "input"]);
return status;
},
object: ["WebGLRenderingContext", "WebGL2RenderingContext"],
fakeGenerator: function(checker){
return function readPixels(x, y, width, height, format, type, pixels){ // eslint-disable-line max-params
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
notify("fakedReadout");
var fakeCanvas = getFakeCanvas(window, this.canvas, prefs);
var {context} = copyCanvasToWebgl(
window,
fakeCanvas,
this instanceof window.WebGLRenderingContext? "webgl": "webgl2"
);
return original.apply(context, window.Array.from(args));
}
else {
return original.apply(this, window.Array.from(args));
}
});
};
}
},
getParameter: {
type: "readout",
getStatus: function(obj, status, prefs){
const protectedPartChecker = getProtectedPartChecker(prefs, status.url);
status = Object.create(status);
status.active = protectedPartChecker(["readout", "input"]);
return status;
},
object: ["WebGLRenderingContext", "WebGL2RenderingContext"],
fakeGenerator: function(checker){
function getNumber(originalValue, max, index, window){
const bitLength = Math.floor(Math.log2(max) + 1);
const rng = randomSupply.getBitRng(bitLength, window);
let value = 0;
for (let i = 0; i < bitLength; i += 1){
value <<= 1;
value ^= rng(originalValue, index + i);
}
return value;
}
const types = {
decimal: function(originalValue, definition, window){
const int = Math.floor(originalValue);
if (int !== originalValue){
const decimal = originalValue - int;
const rng = randomSupply.getRng(1, window);
const newDecimal = decimal * (rng(definition.pname) / 0xFFFFFFFF);
return int + newDecimal;
}
else {
return originalValue;
}
},
shift: function(originalValue, definition, window){
const value = getNumber(originalValue, definition.max, definition.pname, window);
return originalValue >>> value;
},
"-": function(originalValue, definition, window){
const value = getNumber(originalValue, definition.max, definition.pname, window) *
(definition.factor || 1);
if (value > originalValue){
return 0;
}
return originalValue - value;
}
};
const changeDefinition = {
2928: {name: "DEPTH_RANGE", type: "decimal", isArray: true},
3379: {name: "MAX_TEXTURE_SIZE", type: "shift", max: 1},
3386: {name: "MAX_VIEWPORT_DIMS", type: "shift", max: 1, isArray: true},
32883: {name: "MAX_3D_TEXTURE_SIZE", type: "shift", max: 1},
33000: {name: "MAX_ELEMENTS_VERTICES", type: "-", max: 3, factor: 50},
33001: {name: "MAX_ELEMENTS_INDICES", type: "-", max: 3, factor: 50},
33901: {name: "ALIASED_POINT_SIZE_RANGE", type: "decimal", isArray: true},
33902: {name: "ALIASED_LINE_WIDTH_RANGE", type: "decimal", isArray: true},
34024: {name: "MAX_RENDERBUFFER_SIZE", type: "shift", max: 1},
34045: {name: "MAX_TEXTURE_LOD_BIAS", type: "-", max: 1, factor: 1},
34076: {name: "MAX_CUBE_MAP_TEXTURE_SIZE", type: "shift", max: 1},
34921: {name: "MAX_VERTEX_ATTRIBS", type: "shift", max: 1},
34930: {name: "MAX_TEXTURE_IMAGE_UNITS", type: "shift", max: 1},
35071: {name: "MAX_ARRAY_TEXTURE_LAYERS", type: "shift", max: 1},
35371: {name: "MAX_VERTEX_UNIFORM_BLOCKS", type: "-", max: 1, factor: 1},
35373: {name: "MAX_FRAGMENT_UNIFORM_BLOCKS", type: "-", max: 1, factor: 1},
35374: {name: "MAX_COMBINED_UNIFORM_BLOCKS", type: "-", max: 3, factor: 1},
35375: {name: "MAX_UNIFORM_BUFFER_BINDINGS", type: "-", max: 3, factor: 1},
35376: {name: "MAX_UNIFORM_BLOCK_SIZE", type: "shift", max: 1},
35377: {name: "MAX_COMBINED_VERTEX_UNIFORM_COMPONENTS", type: "-", max: 7, factor: 10},
35379: {name: "MAX_COMBINED_FRAGMENT_UNIFORM_COMPONENTS", type: "-", max: 7, factor: 10},
35657: {name: "MAX_FRAGMENT_UNIFORM_COMPONENTS", type: "shift", max: 1},
35658: {name: "MAX_VERTEX_UNIFORM_COMPONENTS", type: "shift", max: 1},
35659: {name: "MAX_VARYING_COMPONENTS", type: "shift", max: 1},
35660: {name: "MAX_VERTEX_TEXTURE_IMAGE_UNITS", type: "shift", max: 1},
35661: {name: "MAX_COMBINED_TEXTURE_IMAGE_UNITS", type: "-", max: 1, factor: 2},
35968: {name: "MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS", type: "shift", max: 1},
35978: {name: "MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS", type: "shift", max: 1},
36203: {name: "MAX_ELEMENT_INDEX", type: "-", max: 15, factor: 1},
36347: {name: "MAX_VERTEX_UNIFORM_VECTORS", type: "shift", max: 1},
36348: {name: "MAX_VARYING_VECTORS", type: "shift", max: 1},
36349: {name: "MAX_FRAGMENT_UNIFORM_VECTORS", type: "shift", max: 1},
37154: {name: "MAX_VERTEX_OUTPUT_COMPONENTS", type: "shift", max: 1},
37157: {name: "MAX_FRAGMENT_INPUT_COMPONENTS", type: "shift", max: 1},
7936: {name: "VENDOR", fake: function(originalValue, window, prefs){
const settingValue = prefs("webGLVendor") || originalValue;
return {value: settingValue, faked: settingValue === originalValue};
}},
7937: {name: "RENDERER", fake: function(originalValue, window, prefs){
const settingValue = prefs("webGLRenderer") || originalValue;
return {value: settingValue, faked: settingValue === originalValue};
}},
37445: {name: "UNMASKED_VENDOR_WEBGL", fake: function(originalValue, window, prefs){
const settingValue = prefs("webGLUnmaskedVendor") || originalValue;
return {value: settingValue, faked: settingValue === originalValue};
}},
37446: {name: "UNMASKED_RENDERER_WEBGL", fake: function(originalValue, window, prefs){
const settingValue = prefs("webGLUnmaskedRenderer") || originalValue;
return {value: settingValue, faked: settingValue === originalValue};
}}
};
const parameterNames = Object.keys(changeDefinition);
parameterNames.forEach(function(parameterName){
const definition = changeDefinition[parameterName];
definition.pname = parameterName;
if (!definition.fake){
definition.fake = definition.isArray?
function fake(originalValue, window){
let faked = false;
let fakedValue = [];
for (var i = 0; i < originalValue.length; i += 1){
fakedValue[i] = types[this.type](originalValue[i], this, window);
faked |= originalValue[i] === fakedValue[i];
originalValue[i] = fakedValue[i];
}
this.fake = function(originalValue){
if (faked){
for (var i = 0; i < originalValue.length; i += 1){
originalValue[i] = fakedValue[i];
}
}
return {
value: originalValue,
faked
};
};
return {
value: originalValue,
faked
};
}:
function fake(originalValue, window){
let value = types[this.type](originalValue, this, window);
let faked = value === originalValue;
this.fake = function(){
return {value, faked};
};
return {value, faked};
};
}
});
return function getParameter(pname){
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
const originalValue = original.apply(this, window.Array.from(args));
if (changeDefinition[pname]){
const definition = changeDefinition[pname];
const {value, faked} = definition.fake(originalValue, window, prefs);
if (faked){
notify("fakedReadout");
}
return value;
}
else {
return originalValue;
}
});
};
}
}
};
Object.keys(scope.changedFunctions).forEach(function(key){
scope.changedFunctions[key].api = "canvas";
});
}());