From 91b814ce7e604ca8e29adf31ffb15638796036c1 Mon Sep 17 00:00:00 2001
From: kkapsner <github@mail.kkapsner.de>
Date: Sun, 10 Feb 2019 02:55:45 +0100
Subject: [PATCH] Improved audio API protection

reduced detection
more consistent faking
---
 lib/modifiedAudioAPI.js | 23 +++++++++++++++++++----
 releaseNotes.txt        |  6 ++++--
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/lib/modifiedAudioAPI.js b/lib/modifiedAudioAPI.js
index 1b5219d..6a54b80 100644
--- a/lib/modifiedAudioAPI.js
+++ b/lib/modifiedAudioAPI.js
@@ -89,8 +89,17 @@
 	const floatCache = Object.create(null);
 	const intCache = Object.create(null);
 	
+	function arrayHasAnyNonZero(array){
+		for (var i = 0, l = array.length; i < l; i += 1){
+			if (array[i]){
+				return true;
+			}
+		}
+		return false;
+	}
+	
 	function fakeFloat32Array(array, window, prefs){
-		if (prefs("protectAudio", window.location)){
+		if (arrayHasAnyNonZero(array)){
 			let cached = false;
 			let hash;
 			if (prefs("useAudioCache")){
@@ -113,6 +122,7 @@
 				});
 				if (prefs("useAudioCache")){
 					floatCache[hash] = new window.Float32Array(array);
+					floatCache[hashing(array)] = new window.Float32Array(array);
 				}
 			}
 			else {
@@ -121,7 +131,7 @@
 		}
 	}
 	function fakeUint8Array(array, window, prefs){
-		if (prefs("protectAudio", window.location)){
+		if (arrayHasAnyNonZero(array)){
 			let cached = false;
 			let hash;
 			if (prefs("useAudioCache")){
@@ -136,6 +146,7 @@
 				});
 				if (prefs("useAudioCache")){
 					intCache[hash] = new window.Uint8Array(array);
+					intCache[hashing(array)] = new window.Uint8Array(array);
 				}
 			}
 			else {
@@ -236,9 +247,13 @@
 				return function copyFromChannel(destination, channelNumber, startInChannel){
 					return checkerWrapper(checker, this, arguments, function(args, check){
 						var {prefs, notify, window, original} = check;
-						notify("fakedAudioReadout");
+						var channelData = this.getChannelData(channelNumber);
+						if (!getChannelDataAlreadyFakedArrays.get(channelData)){
+							notify("fakedAudioReadout");
+							fakeFloat32Array(channelData, window, prefs);
+							getChannelDataAlreadyFakedArrays.set(channelData, true);
+						}
 						var ret = original.apply(this, window.Array.from(args));
-						fakeFloat32Array(destination, window, prefs);
 						return ret;
 					});
 				};
diff --git a/releaseNotes.txt b/releaseNotes.txt
index 8f76f5e..52754ad 100644
--- a/releaseNotes.txt
+++ b/releaseNotes.txt
@@ -1,9 +1,11 @@
 Version 0.5.8:
 	changes:
-		- 
+		- audio faking will not alter buffers with only zero values
 	
 	new features:
-		- Added cache for getChannelData
+		- added combined cache for getChannelData and copyFromChannel:
+			- better performance
+			- prevent double faking => prevent detection
 	
 	fixes:
 		- after reset the hidden settings and expanded views were not reset