Added protection for audio API

lib/modifiedAudioAPI.js

@@ -0,0 +1,191 @@
+/* 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 scope;
+	if ((typeof exports) !== "undefined"){
+		scope = exports;
+	}
+	else {
+		window.scope.modifiedAudioAPI = {};
+		scope = window.scope.modifiedAudioAPI;
+	}
+	
+	const logging = require("./logging");
+	const getWrapped = require("sdk/getWrapped");
+	
+	var randomSupply = null;
+	
+	const audioFakeRate = {
+		"1": function(array){return 1;},
+		"10": function(array){return 10;},
+		"100": function(array){return 100;},
+		"1000": function(array){return 1000;},
+		"0.1%": function(array){return array.length / 1000;},
+		"1%": function(array){return array.length / 100;},
+	};
+	function getAudioFakeRate(array, prefs){
+		var func = audioFakeRate[prefs("audioFakeRate")];
+		if (typeof func === "function"){
+			return func(array);
+		}
+		else {
+			return 10;
+		}
+	}
+	const audioNoiseLevel = {
+		"minimal": 0.0000001,
+		"low": 0.00001,
+		"medium": 0.001,
+		"high": 0.01,
+		"maximal": 0.1
+	};
+	function getAudioNoiseLevel(prefs){
+		return audioNoiseLevel[prefs("audioNoiseLevel")] || 0.0000001;
+	}
+	
+	function fakeFloat32Array(array, window, prefs){
+		if (prefs("protectAudio")){
+			var l = array.length;
+			var rate = getAudioFakeRate(array, prefs);
+			var noiseLevel = getAudioNoiseLevel(prefs);
+			var indexRng = randomSupply.getIndexRng(rate, l, window);
+			var rng = randomSupply.getRng(rate, window);
+			for (var i = 0; i < rate; i += 1){
+				var index = indexRng(i);
+				array[index] += (rng(i) / 0xffffffff - 0.5) * noiseLevel;
+			}
+		}
+	}
+	function fakeUint8Array(array, window, prefs){
+		if (prefs("protectAudio")){
+			var l = array.length;
+			var rate = getAudioFakeRate(array, prefs);
+			var indexRng = randomSupply.getIndexRng(rate, l, window);
+			var rng = randomSupply.getValueRng(rate, window);
+			for (var i = 0; i < rate; i += 1){
+				var index = indexRng(i);
+				array[index] = rng(array[index], i);
+			}
+		}
+	}
+	
+	function hasType(status, type){
+		return status.type.indexOf(type) !== -1;
+	}
+	
+	scope.setRandomSupply = function(supply){
+		randomSupply = supply;
+	};
+	
+	function getStatus(obj, status){
+		status = Object.create(status);
+		status.active = hasType(status, "readout");
+		return status;
+	}
+	
+	let notified = false;
+	function notifyOnce(notify){
+		if (!notified){
+			notify("fakedAudioReadout");
+			notified = true;
+		}
+	}
+	// changed functions and their fakes
+	scope.changedFunctions = {
+		getFloatFrequencyData: {
+			type: "readout",
+			getStatus: getStatus,
+			object: ["AnalyserNode"],
+			fakeGenerator: function(prefs, notify, window, original){
+				return function getFloatFrequencyData(array){
+					notifyOnce(notify);
+					var ret = original.apply(this, window.Array.from(arguments));
+					fakeFloat32Array(array, window, prefs);
+					return ret;
+				};
+			}
+		},
+		getByteFrequencyData: {
+			type: "readout",
+			getStatus: getStatus,
+			object: ["AnalyserNode"],
+			fakeGenerator: function(prefs, notify, window, original){
+				return function getByteFrequencyData(array){
+					notifyOnce(notify);
+					var ret = original.apply(this, window.Array.from(arguments));
+					fakeUint8Array(array, window, prefs);
+					return ret;
+				};
+			}
+		},
+		getFloatTimeDomainData: {
+			type: "readout",
+			getStatus: getStatus,
+			object: ["AnalyserNode"],
+			fakeGenerator: function(prefs, notify, window, original){
+				return function getFloatTimeDomainData(array){
+					notifyOnce(notify);
+					var ret = original.apply(this, window.Array.from(arguments));
+					fakeFloat32Array(array, window, prefs);
+					return ret;
+				};
+			}
+		},
+		getByteTimeDomainData: {
+			type: "readout",
+			getStatus: getStatus,
+			object: ["AnalyserNode"],
+			fakeGenerator: function(prefs, notify, window, original){
+				return function getByteTimeDomainData(array){
+					notifyOnce(notify);
+					var ret = original.apply(this, window.Array.from(arguments));
+					fakeUint8Array(array, window, prefs);
+					return ret;
+				};
+			}
+		},
+		getChannelData: {
+			type: "readout",
+			getStatus: getStatus,
+			object: ["AudioBuffer"],
+			fakeGenerator: function(prefs, notify, window, original){
+				return function getChannelData(channel){
+					notifyOnce(notify);
+					var ret = original.apply(this, window.Array.from(arguments));
+					fakeFloat32Array(ret, window, prefs);
+					return ret;
+				};
+			}
+		},
+		copyFromChannel: {
+			type: "readout",
+			getStatus: getStatus,
+			object: ["AudioBuffer"],
+			fakeGenerator: function(prefs, notify, window, original){
+				return function copyFromChannel(destination, channelNumber, startInChannel){
+					notifyOnce(notify);
+					var ret = original.apply(this, window.Array.from(arguments));
+					fakeFloat32Array(destination, window, prefs);
+					return ret;
+				};
+			}
+		},
+		getFrequencyResponse: {
+			type: "readout",
+			getStatus: getStatus,
+			object: ["BiquadFilterNode", "IIRFilterNode"],
+			fakeGenerator: function(prefs, notify, window, original){
+				return function getFrequencyResponse(frequencyArray, magResponseOutput, phaseResponseOutput){
+					notifyOnce(notify);
+					var ret = original.apply(this, window.Array.from(arguments));
+					fakeFloat32Array(magResponseOutput, window, prefs);
+					fakeFloat32Array(phaseResponseOutput, window, prefs);
+					return ret;
+				};
+			}
+		},
+	};
+}());