mirror of
https://github.com/kkapsner/CanvasBlocker
synced 2024-07-05 00:29:17 +02:00
210 lines
4.9 KiB
JavaScript
210 lines
4.9 KiB
JavaScript
/* global self, window, console, unsafeWindow */
|
|
(function(){
|
|
"use strict";
|
|
|
|
var blockMode = {
|
|
getContext: {
|
|
status: "block",
|
|
askStatus: {
|
|
askOnce: false,
|
|
alreadyAsked: false,
|
|
answer: null
|
|
}
|
|
},
|
|
readAPI: {
|
|
status: "allow"
|
|
}
|
|
};
|
|
|
|
var undef;
|
|
var originalGetContext = unsafeWindow.HTMLCanvasElement.prototype.getContext;
|
|
Object.defineProperty(
|
|
unsafeWindow.HTMLCanvasElement.prototype,
|
|
"getContext",
|
|
{
|
|
enumerable: true,
|
|
configureable: false,
|
|
get: exportFunction(function(){
|
|
switch (blockMode.getContext.status){
|
|
case "allow":
|
|
// console.log("allow");
|
|
return originalGetContext;
|
|
case "ask":
|
|
// console.log("ask");
|
|
var status = blockMode.getContext.askStatus;
|
|
var allow;
|
|
if (status.askOnce && status.alreadyAsked){
|
|
// console.log("already asked");
|
|
allow = status.answer;
|
|
}
|
|
else {
|
|
// console.log("asking");
|
|
allow = window.confirm(_("askForPermission"));
|
|
status.alreadyAsked = true;
|
|
status.answer = allow;
|
|
}
|
|
return allow? originalGetContext: undef;
|
|
case "block":
|
|
default:
|
|
// console.log("block");
|
|
return undef;
|
|
}
|
|
}, unsafeWindow)
|
|
}
|
|
);
|
|
|
|
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;
|
|
}());
|
|
|
|
var originalToDataURL = unsafeWindow.HTMLCanvasElement.prototype.toDataURL;
|
|
Object.defineProperty(
|
|
unsafeWindow.HTMLCanvasElement.prototype,
|
|
"toDataURL",
|
|
{
|
|
enumerable: true,
|
|
configureable: false,
|
|
get: exportFunction(function(){
|
|
switch (blockMode.readAPI.status){
|
|
case "allow":
|
|
return originalToDataURL;
|
|
case "block":
|
|
default:
|
|
return exportFunction(
|
|
function(){
|
|
var type = arguments[0] || "image/png";
|
|
return "data:" + type + ";base64," + btoa(randomImage);
|
|
},
|
|
unsafeWindow
|
|
);
|
|
}
|
|
}, unsafeWindow)
|
|
}
|
|
);
|
|
|
|
var originalToBlob = unsafeWindow.HTMLCanvasElement.prototype.toBlob;
|
|
Object.defineProperty(
|
|
unsafeWindow.HTMLCanvasElement.prototype,
|
|
"toBlob",
|
|
{
|
|
enumerable: true,
|
|
configureable: false,
|
|
get: exportFunction(function(){
|
|
switch (blockMode.readAPI.status){
|
|
case "allow":
|
|
return originalToBlob;
|
|
case "block":
|
|
default:
|
|
return exportFunction(
|
|
function(callback){
|
|
var type = arguments[0] || "image/png";
|
|
var blob = new window.Blob(randomImage, {type: type});
|
|
callback(blob);
|
|
},
|
|
unsafeWindow,
|
|
{allowCallbacks: true}
|
|
);
|
|
}
|
|
}, unsafeWindow)
|
|
}
|
|
);
|
|
|
|
var originalMozGetAsFile = unsafeWindow.HTMLCanvasElement.prototype.mozGetAsFile;
|
|
Object.defineProperty(
|
|
unsafeWindow.HTMLCanvasElement.prototype,
|
|
"mozGetAsFile",
|
|
{
|
|
enumerable: true,
|
|
configureable: false,
|
|
get: exportFunction(function(){
|
|
switch (blockMode.readAPI.status){
|
|
case "allow":
|
|
return originalMozGetAsFile;
|
|
case "block":
|
|
default:
|
|
undef
|
|
}
|
|
}, unsafeWindow)
|
|
}
|
|
);
|
|
|
|
var originalGetImageData = unsafeWindow.CanvasRenderingContext2D.prototype.getImageData;
|
|
Object.defineProperty(
|
|
unsafeWindow.CanvasRenderingContext2D.prototype,
|
|
"getImageData",
|
|
{
|
|
enumerable: true,
|
|
configureable: false,
|
|
get: exportFunction(function(){
|
|
switch (blockMode.readAPI.status){
|
|
case "allow":
|
|
return originalGetImageData;
|
|
case "block":
|
|
default:
|
|
return exportFunction(
|
|
function(sx, sy, sw, sh){
|
|
var imageData = new window.ImageData(sw, sh);
|
|
var l = sw * sh * 4;
|
|
for (var i = 0; i < l; i += 1){
|
|
imageData.data[i] = Math.floor(
|
|
Math.random() * 256
|
|
);
|
|
}
|
|
return imageData;
|
|
},
|
|
unsafeWindow
|
|
);
|
|
}
|
|
}, unsafeWindow)
|
|
}
|
|
);
|
|
|
|
var _ = function(name){
|
|
return _[name] || name;
|
|
};
|
|
self.port.on("setTranslation", function(name, translation){
|
|
_[name] = translation;
|
|
});
|
|
|
|
function checkPDF(blocking){
|
|
if (document.contentType.match(/\/pdf$/i)){
|
|
self.port.emit("isPDF", blocking);
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
self.port.on("block", function(force){
|
|
if (force || !checkPDF("block")){
|
|
blockMode.getContext.status = "block";
|
|
blockMode.readAPI.status = "allow";
|
|
}
|
|
});
|
|
self.port.on("ask", function(force, askOnce){
|
|
if (force || !checkPDF("askVisible")){
|
|
blockMode.getContext.status = "ask";
|
|
blockMode.getContext.askStatus.askOnce = askOnce;
|
|
blockMode.readAPI.status = "allow";
|
|
}
|
|
});
|
|
self.port.on("blockReadout", function(force){
|
|
if (force || !checkPDF("blockReadout")){
|
|
blockMode.getContext.status = "allow";
|
|
blockMode.readAPI.status = "block";
|
|
}
|
|
});
|
|
self.port.on("unblock", function(){
|
|
blockMode.getContext.status = "allow";
|
|
blockMode.readAPI.status = "allow";
|
|
});
|
|
self.port.on("detach", function(force){
|
|
blockMode.getContext.status = "allow";
|
|
blockMode.readAPI.status = "allow";
|
|
});
|
|
}());
|