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mirror of https://github.com/kkapsner/CanvasBlocker synced 2024-11-04 20:28:52 +01:00
CanvasBlocker/data/inject.js
2015-04-24 01:04:14 +02:00

317 lines
8.4 KiB
JavaScript

/* global self, window, CanvasRenderingContext2D, WebGLRenderingContext, console, unsafeWindow, exportFunction, cloneInto, checkURL, getDomainRegExpList */
/* 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";
var settings = {
showCallingFile: false,
showCompleteCallingStack: false
};
var blockMode = {
getContext: {
name: "getContext",
status: "block",
askText: {
visible: "askForVisiblePermission",
invisible: "askForInvisiblePermission",
nocanvas: "askForPermission"
},
askStatus: {
askOnce: false,
alreadyAsked: {},
answer: {}
}
},
readAPI: {
name: "readAPI",
status: "allow",
askText: {
visible: "askForVisibleReadoutPermission",
invisible: "askForInvisibleReadoutPermission",
nocanvas: "askForReadoutPermission"
},
askStatus: {
askOnce: false,
alreadyAsked: {},
answer: {}
}
}
};
var undef;
var randomImage = (function(){
var length = Math.floor(20 + Math.random() * 100);
var bytes = "";
for (var i = 0; i < length; i += 1){
bytes += String.fromCharCode(Math.floor(Math.random() * 256));
}
return bytes;
}());
// parse calling stack
function errorToCallingStackMsg(error){
var msg = "";
var callers = error.stack.trim().split("\n");
//console.log(callers);
var findme = callers.shift(); // Remove us from the stack
findme = findme.replace(/(:[0-9]+){1,2}$/, ""); // rm line & column
// Eliminate squashed stack. stack may contain 2+ stacks, but why...
var inDoubleStack = false;
callers = callers.filter(function(caller){
var doubleStackStart = caller.search(findme) !== -1;
inDoubleStack = inDoubleStack || doubleStackStart;
return !inDoubleStack;
});
msg += "\n\n" + _("sourceOutput") + ": ";
if (settings.showCompleteCallingStack){
msg += callers.reduce(function(stack, c){
return stack + "\n\t" + _("stackEntryOutput", parseStackEntry(c));
}, "");
}
else{
msg += _("stackEntryOutput", parseStackEntry(callers[0]));
}
return msg;
}
// Check canvas appearance
function canvasAppearance(context){
var oldBorder = false;
var canvas = false;
var inDOM = null;
if (context){
if (context.nodeName === "CANVAS"){
canvas = context;
}
else if (
context instanceof CanvasRenderingContext2D ||
context instanceof WebGLRenderingContext
){
canvas = context.canvas;
}
}
if (canvas){
oldBorder = canvas.style.border;
canvas.style.border = "2px solid red";
inDOM = canvas.ownerDocument.contains(canvas);
}
return {
canvas: canvas,
askCategory: canvas? (inDOM? "visible": "invisible"): "nocanvas",
get text(){
var text = canvas? (this.visible? "visible": "invisible"): "nocanvas";
Object.defineProperty(this, "text", {value: text});
return text;
},
inDom: inDOM,
get visible(){
var visible = inDOM;
if (inDOM){
canvas.scrollIntoView();
var rect = canvas.getBoundingClientRect();
var foundEl = document.elementFromPoint(rect.left + rect.width / 2, rect.top + rect.height / 2);
visible = (foundEl === canvas);
}
Object.defineProperty(this, "visible", {value: visible});
return visible;
},
reset: function(){
if (canvas){
canvas.style.border = oldBorder;
}
}
};
}
// changed functions
var changedFunctions = {
getContext: {
mode: blockMode.getContext,
object: unsafeWindow.HTMLCanvasElement
},
toDataURL: {
mode: blockMode.readAPI,
object: unsafeWindow.HTMLCanvasElement,
fake: function(){
var type = arguments[0] || "image/png";
return "data:" + type + ";base64," + btoa(randomImage);
}
},
toBlob: {
mode: blockMode.readAPI,
object: unsafeWindow.HTMLCanvasElement,
fake: function(callback){
var type = arguments[0] || "image/png";
var blob = new window.Blob(randomImage, {type: type});
callback(blob);
},
exportOptions: {allowCallbacks: true}
},
mozGetAsFile: {
mode: blockMode.readAPI,
object: unsafeWindow.HTMLCanvasElement
},
getImageData: {
mode: blockMode.readAPI,
object: unsafeWindow.CanvasRenderingContext2D,
fake: function(sx, sy, sw, sh){
var l = sw * sh * 4;
var data = new Uint8ClampedArray(l);
for (var i = 0; i < l; i += 1){
data[i] = Math.floor(
Math.random() * 256
);
}
var imageData = new window.ImageData(sw, sh);
imageData.data.set(cloneInto(data, unsafeWindow));
return imageData;
}
},
readPixels: {
mode: blockMode.readAPI,
object: unsafeWindow.WebGLRenderingContext,
fake: function(x, y, width, height, format, type, pixels){
// fake not working due to XRay copy restrictions...
// for (var i = 0; i < pixels.length; i += 1){
// pixels[i] = Math.floor(
// Math.random() * 256
// );
// }
}
}
};
Object.keys(changedFunctions).forEach(function(name){
var changedFunction = changedFunctions[name];
var original = changedFunction.object.prototype[name];
Object.defineProperty(
changedFunction.object.prototype,
name,
{
enumerable: true,
configureable: false,
get: exportFunction(function(){
var status = changedFunction.mode.status;
var callingStackMsg = errorToCallingStackMsg(new Error());
if (status === "ask"){
var askStatus = changedFunction.mode.askStatus;
var appearance = canvasAppearance(this);
if (askStatus.askOnce && askStatus.alreadyAsked[appearance.askCategory]){
// console.log("already asked");
status = askStatus.answer[appearance.askCategory];
}
else {
//console.log("asking");
var msg = _(changedFunction.mode.askText[appearance.text]);
if (settings.showCallingFile){
msg += callingStackMsg;
}
status = window.confirm(msg) ? "allow": "block";
askStatus.alreadyAsked[appearance.text] = true;
askStatus.answer[appearance.text] = status;
//console.log("asking (done)");
appearance.reset();
}
}
self.port.emit("accessed " + changedFunction.mode.name, status, callingStackMsg);
switch (status){
case "allow":
return original;
case "fake":
return changedFunction.fake? exportFunction(
changedFunction.fake,
unsafeWindow,
changedFunction.exportOptions
): undef;
//case "block":
default:
return undef;
}
}, unsafeWindow)
}
);
});
// Stack parsing
function parseStackEntry(entry){
var m = /@(.*):(\d*):(\d*)$/.exec(entry) || ["", entry, "--", "--"];
return {
url: m[1],
line: m[2],
column: m[3],
raw: entry
};
}
// Translation
var _ = function(name, replace){
var str = self.options.translations[name] || name;
if (replace){
Object.keys(replace).forEach(function(name){
str = str.replace(new RegExp("{" + name + "}", "g"), replace[name]);
});
}
return str;
};
// Communication with main.js
function setStatus(mode, askOnce){
switch (mode){
case "block":
blockMode.getContext.status = "block";
blockMode.readAPI.status = "block";
break;
case "ask":
blockMode.getContext.status = "ask";
blockMode.getContext.askStatus.askOnce = askOnce;
blockMode.readAPI.status = "allow";
break;
case "blockReadout":
blockMode.getContext.status = "allow";
blockMode.readAPI.status = "block";
break;
case "fakeReadout":
blockMode.getContext.status = "allow";
blockMode.readAPI.status = "fake";
break;
case "askReadout":
blockMode.getContext.status = "allow";
blockMode.readAPI.status = "ask";
blockMode.readAPI.askStatus.askOnce = askOnce;
break;
case "unblock":
blockMode.getContext.status = "allow";
blockMode.readAPI.status = "allow";
break;
case "detach":
blockMode.getContext.status = "allow";
blockMode.readAPI.status = "allow";
break;
}
}
["block", "ask", "blockReadout", "fakeReadout", "askReadout", "unblock", "detach"].forEach(function(mode){
self.port.on(mode, function(askOnce){
setStatus(mode, askOnce);
});
});
setStatus(
checkURL(
location,
self.options.blockMode,
getDomainRegExpList(self.options.whiteList),
getDomainRegExpList(self.options.blackList)
),
self.options.askOnce
);
// settings passthrough
self.port.on("set", function(name, value){
settings[name] = value;
});
}());