CanvasBlocker/test/detectionTest.js

/* eslint no-console: off */
var addTest = (function(){
	"use strict";

	var stati = [
		{className: "notRun", text: "not run"},
		{className: "loud", text: "CB detected"},
		{className: "stealthy", text: "CB not detected"},
		{className: "failed", text: "test failed"}
	];
	var ul = document.getElementById("tests");
	return function addTest(name, func){
		var logs = [];
		function log(){
			logs.push(Array.prototype.slice.call(arguments).join(" "));
		}
		var status = 0;
		try {
			status = func(log)? 1: 2;
		}
		catch (e){
			console.log(e);
			status = 3;
		}
		var li = document.createElement("li");
		li.className = stati[status].className;
		var nameNode = document.createElement("span");
		nameNode.className = "name";
		nameNode.textContent = name;
		nameNode.title = func.toString();
		li.appendChild(nameNode);
		li.appendChild(document.createTextNode(": "));
		var statusNode = document.createElement("span");
		statusNode.className = "status";
		statusNode.textContent = stati[status].text;
		statusNode.title = logs.join("\n");
		li.appendChild(statusNode);
		ul.appendChild(li);
	};
}());

addTest("function length", function(log){
	"use strict";
	
	if (CanvasRenderingContext2D.prototype.getImageData.length !== 4){
		log("expected 4 parameters for getImageData - got", CanvasRenderingContext2D.prototype.getImageData.length);
		return true;
	}
	else {
		return false;
	}
});
addTest("function code", function(log){
	"use strict";
	
	if (!CanvasRenderingContext2D.prototype.getImageData.toString().match(
		/^\s*function getImageData\s*\(\)\s*\{\s*\[native code\]\s*\}\s*$/
	)){
		log("unexpected function code:", CanvasRenderingContext2D.prototype.getImageData.toString());
		return true;
	}
	else {
		return false;
	}
});
addTest("function name", function(){
	"use strict";
	
	return CanvasRenderingContext2D.prototype.getImageData.name !== "getImageData";
});
addTest("property descriptor", function(log){
	"use strict";
	
	const properties = [
		{
			object: CanvasRenderingContext2D.prototype,
			name: "getImageData",
			descriptor: {
				value: function getImageData(x, y, w, h){},
				writable: true,
				enumerable: true,
				configurable: true
			}
		},
		{
			object: HTMLCanvasElement.prototype,
			name: "toDataURL",
			descriptor: {
				value: function toDataURL(){},
				writable: true,
				enumerable: true,
				configurable: true
			}
		},
	];
	
	return properties.reduce(function(pass, property){
		const desiredDescriptor = property.descriptor;
		const descriptor = Object.getOwnPropertyDescriptor(property.object, property.name);
		return Object.keys(desiredDescriptor).reduce(function(pass, key){
			function keyLog(type, expected, got){
				log(property.name + ": wrong " + type + " for ", key, "- expected:", expected, "- got:", got);
			}
			var desiredValue = desiredDescriptor[key];
			var value = descriptor[key];
			var keyPass = false;
			if ((typeof desiredValue) === (typeof value)){
				if ((typeof desiredValue) === "function"){
					if (value.name !== desiredValue.name){
						keyPass = true;
						keyLog("function name", desiredValue.name, value.name);
						
					}
					if (value.length !== desiredValue.length){
						keyPass = true;
						keyLog("function length", desiredValue.length, value.length);
					}
				}
				else {
					if (desiredValue !== value){
						keyPass = true;
						keyLog("value", desiredValue, value);
					}
				}
			}
			else {
				keyPass = true;
				keyLog("type", typeof desiredValue, typeof value);
			}
			return pass || keyPass;
		}, false) || pass;
	}, false);
});
addTest("error provocation 1", function(log){
	"use strict";
	
	var canvas = document.createElement("canvas");
	var ctx = canvas.getContext("2d");
	var canvasBlocker = false;
	try{
		ctx.getImageData(0, 0, 0, 0);
	}
	catch (err){
		try {
			log(err.name);
			log(err.toString());
		}
		catch (e){
			canvasBlocker = true;
		}
	}
	return canvasBlocker;
});
addTest("error provocation 2", function(log){
	"use strict";
	
	var canvas = document.createElement("canvas");
	canvas.width = 0;
	var ctx = canvas.getContext("2d");
	var canvasBlocker = false;
	try{
		ctx.getImageData(0, 0, 1, 1);
		log("no error provoked");
	}
	catch (err){
		try {
			log(err.name);
			log(err.toString());
		}
		catch (e){
			canvasBlocker = true;
		}
	}
	return canvasBlocker;
});
addTest("error provocation 3", function(log){
	"use strict";
	
	var canvasBlocker = false;
	try{
		CanvasRenderingContext2D.prototype.getImageData.apply(undefined, [0, 0, 1, 1]);
	}
	catch (err){
		try {
			log(err.name);
			log(err.toString());
		}
		catch (e){
			canvasBlocker = true;
		}
	}
	return canvasBlocker;
});
addTest("error properties", function(log){
	"use strict";
	
	var canvasBlocker = false;
	try{
		CanvasRenderingContext2D.prototype.getImageData.apply(undefined, [0, 0, 1, 1]);
	}
	catch (err){
		try {
			var name = "TypeError";
			if (err.name !== name && err instanceof TypeError){
				log("Error name wrong. Expected: ", name, "- got:", err.name);
				canvasBlocker = true;
			}
			var start = "@" + location.href.replace(/\.html$/, ".js");
			if (!err.stack.startsWith(start)){
				log("Error stack starts wrong. Expected:", start, "- got :", err.stack.split(/\n/g, 2)[0]);
				canvasBlocker = true;
			}
			var message = "'getImageData' called on an object that " +
				"does not implement interface CanvasRenderingContext2D.";
			if (err.message !== message){
				log("Error message wrong. Expected: ", message, "- got:", err.message);
				canvasBlocker = true;
			}
		}
		catch (e){
			canvasBlocker = true;
		}
	}
	return canvasBlocker;
});
function testKnownPixelValue(size, log){
	"use strict";
	
	var canvas = document.createElement("canvas");
	canvas.height = size;
	canvas.width = size;
	var context = canvas.getContext("2d");
	var imageData = new ImageData(canvas.width, canvas.height);
	var pixelValues = imageData.data;
	for (let i = 0; i < imageData.data.length; i += 1){
		if (i % 4 !== 3){
			pixelValues[i] = Math.floor(256 * Math.random());
		}
		else {
			pixelValues[i] = 255;
		}
	}
	context.putImageData(imageData, 0, 0);
	var p = context.getImageData(0, 0, canvas.width, canvas.height).data;
	for (var i = 0; i < p.length; i += 1){
		if (p[i] !== pixelValues[i]){
			log("wrong value", p[i], "at", i, "expected", pixelValues[i]);
			return true;
		}
	}
	return false;
}
addTest("known pixel value test 1", function(log){
	"use strict";
	
	return testKnownPixelValue(1, log);
});
addTest("known pixel value test 10", function(log){
	"use strict";
	
	return testKnownPixelValue(10, log);
});
addTest("double readout test", function(log){
	"use strict";
	
	var canvas = document.createElement("canvas");
	var context = canvas.getContext("2d");
	var imageData = context.getImageData(0, 0, canvas.width, canvas.height);
	for (let i = 0; i < imageData.data.length; i += 1){
		if (i % 4 !== 3){
			imageData.data[i] = Math.floor(256 * Math.random());
		}
		else {
			imageData.data[i] = 255;
		}
	}
	context.putImageData(imageData, 0, 0);
	
	var imageData1 = context.getImageData(0, 0, canvas.width, canvas.height);
	var imageData2 = context.getImageData(0, 0, canvas.width, canvas.height);
	for (let i = 0; i < imageData2.data.length; i += 1){
		if (imageData1.data[i] !== imageData2.data[i]){
			log("mismatch at", i, ":",
				imageData1.data[i], "(", imageData1.data[i].toString(2), ")",
				"!=",
				imageData2.data[i], "(", imageData2.data[i].toString(2), ")",
				"| original:", imageData.data[i], "(", imageData.data[i].toString(2), ")"
			);
			return true;
		}
	}
	return false;
});
addTest("readout - in - out test", function(log){
	"use strict";
	
	var canvas = document.createElement("canvas");
	var context = canvas.getContext("2d");
	var imageData = context.getImageData(0, 0, canvas.width, canvas.height);
	for (let i = 0; i < imageData.data.length; i += 1){
		if (i % 4 !== 3){
			imageData.data[i] = Math.floor(256 * Math.random());
		}
		else {
			imageData.data[i] = 255;
		}
	}
	context.putImageData(imageData, 0, 0);
	
	var imageData1 = context.getImageData(0, 0, canvas.width, canvas.height);
	var canvas2 = document.createElement("canvas");
	var context2 = canvas2.getContext("2d");
	context2.putImageData(imageData1, 0, 0);
	var imageData2 = context2.getImageData(0, 0, canvas.width, canvas.height);
	for (let i = 0; i < imageData2.data.length; i += 1){
		if (imageData1.data[i] !== imageData2.data[i]){
			log("mismatch at", i, ":",
				imageData1.data[i], "(", imageData1.data[i].toString(2), ")",
				"!=",
				imageData2.data[i], "(", imageData2.data[i].toString(2), ")"
			);
			return true;
		}
	}
	return false;
});