From acb3dc88819b482bbae419a3a36332db30d629f5 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Thu, 21 Nov 2013 12:55:05 -0500
Subject: [PATCH] Add double-free detection code to the pools

---
 .../nvstream/av/AvByteBufferPool.java          | 18 +++++++++++++++++-
 .../limelight/nvstream/av/AvObjectPool.java    | 17 ++++++++++++++++-
 .../nvstream/av/AvShortBufferPool.java         | 18 +++++++++++++++++-
 3 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/src/com/limelight/nvstream/av/AvByteBufferPool.java b/src/com/limelight/nvstream/av/AvByteBufferPool.java
index 1da5e6ad..0fe652af 100644
--- a/src/com/limelight/nvstream/av/AvByteBufferPool.java
+++ b/src/com/limelight/nvstream/av/AvByteBufferPool.java
@@ -6,6 +6,8 @@ public class AvByteBufferPool {
 	private ConcurrentLinkedQueue<byte[]> bufferList = new ConcurrentLinkedQueue<byte[]>();
 	private int bufferSize;
 	
+	private static final boolean doubleFreeDebug = true;
+	
 	public AvByteBufferPool(int size)
 	{
 		this.bufferSize = size;
@@ -18,7 +20,13 @@ public class AvByteBufferPool {
 	
 	public byte[] allocate()
 	{
-		byte[] buff = bufferList.poll();
+		byte[] buff;
+		if (doubleFreeDebug) {
+			buff = null;
+		}
+		else {
+			buff = bufferList.poll();
+		}
 		if (buff == null) {
 			buff = new byte[bufferSize];
 		}
@@ -27,6 +35,14 @@ public class AvByteBufferPool {
 	
 	public void free(byte[] buffer)
 	{
+		if (doubleFreeDebug) {
+			for (byte[] buf : bufferList) {
+				if (buf == buffer) {
+					throw new IllegalStateException("Double free detected");
+				}
+			}
+		}
+		
 		bufferList.add(buffer);
 	}
 }
diff --git a/src/com/limelight/nvstream/av/AvObjectPool.java b/src/com/limelight/nvstream/av/AvObjectPool.java
index 97de612c..d751be98 100644
--- a/src/com/limelight/nvstream/av/AvObjectPool.java
+++ b/src/com/limelight/nvstream/av/AvObjectPool.java
@@ -5,6 +5,8 @@ import java.util.concurrent.ConcurrentLinkedQueue;
 public class AvObjectPool<T> {
 	private ConcurrentLinkedQueue<T> objectList = new ConcurrentLinkedQueue<T>();
 	
+	private static final boolean doubleFreeDebug = true;
+	
 	public void purge()
 	{
 		objectList.clear();
@@ -12,11 +14,24 @@ public class AvObjectPool<T> {
 	
 	public T tryAllocate()
 	{
-		return objectList.poll();
+		if (doubleFreeDebug) {
+			return null;
+		}
+		else {
+			return objectList.poll();
+		}
 	}
 	
 	public void free(T object)
 	{
+		if (doubleFreeDebug) {
+			for (T obj : objectList) {
+				if (obj == object) {
+					throw new IllegalStateException("Double free detected");
+				}
+			}
+		}
+		
 		objectList.add(object);
 	}
 }
diff --git a/src/com/limelight/nvstream/av/AvShortBufferPool.java b/src/com/limelight/nvstream/av/AvShortBufferPool.java
index 012383f8..9f7a956c 100644
--- a/src/com/limelight/nvstream/av/AvShortBufferPool.java
+++ b/src/com/limelight/nvstream/av/AvShortBufferPool.java
@@ -6,6 +6,8 @@ public class AvShortBufferPool {
 	private ConcurrentLinkedQueue<short[]> bufferList = new ConcurrentLinkedQueue<short[]>();
 	private int bufferSize;
 	
+	private static final boolean doubleFreeDebug = true;
+	
 	public AvShortBufferPool(int size)
 	{
 		this.bufferSize = size;
@@ -18,7 +20,13 @@ public class AvShortBufferPool {
 	
 	public short[] allocate()
 	{
-		short[] buff = bufferList.poll();
+		short[] buff;
+		if (doubleFreeDebug) {
+			buff = null;
+		}
+		else {
+			buff = bufferList.poll();
+		}
 		if (buff == null) {
 			buff = new short[bufferSize];
 		}
@@ -27,6 +35,14 @@ public class AvShortBufferPool {
 	
 	public void free(short[] buffer)
 	{
+		if (doubleFreeDebug) {
+			for (short[] buf : bufferList) {
+				if (buf == buffer) {
+					throw new IllegalStateException("Double free detected");
+				}
+			}
+		}
+		
 		bufferList.add(buffer);
 	}
 }