Additional configuration for leak detection

Motivation:

Leak detector, when it detects a leak, will print the last 5 stack
traces that touched the ByteBuf. In some cases that might not be enough
to identify the root cause of the leak.
Also, sometimes users might not be interested in tracing all the
operations on the buffer, but just the ones that are affecting the
reference count.

Modifications:

Added command line properties to override default values:
 * Allow to configure max number of stack traces to collect
 * Allow to only record retain/release operation on buffers

Result:
Users can increase the number of stack traces to debug buffer leaks
with lot of retain/release operations.

buffer/src/main/java/io/netty/buffer/AdvancedLeakAwareByteBuf.java

@@ -17,6 +17,7 @@
 package io.netty.buffer;
 
 import io.netty.util.ResourceLeak;
+import io.netty.util.internal.SystemPropertyUtil;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -29,6 +30,13 @@ import java.nio.charset.Charset;
 
 final class AdvancedLeakAwareByteBuf extends WrappedByteBuf {
 
+    private static final String PROP_ACQUIRE_AND_RELEASE_ONLY = "io.netty.leakDetection.acquireAndReleaseOnly";
+    private static final boolean ACQUIRE_AND_RELEASE_ONLY;
+
+    static {
+        ACQUIRE_AND_RELEASE_ONLY = SystemPropertyUtil.getBoolean(PROP_ACQUIRE_AND_RELEASE_ONLY, false);
+    }
+
     private final ResourceLeak leak;
 
     AdvancedLeakAwareByteBuf(ByteBuf buf, ResourceLeak leak) {
@@ -58,9 +66,15 @@ final class AdvancedLeakAwareByteBuf extends WrappedByteBuf {
         return deallocated;
     }
 
+    private void recordLeakNonRefCountingOperation() {
+        if (!ACQUIRE_AND_RELEASE_ONLY) {
+            leak.record();
+        }
+    }
+
     @Override
     public ByteBuf order(ByteOrder endianness) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         if (order() == endianness) {
             return this;
         } else {
@@ -70,637 +84,637 @@ final class AdvancedLeakAwareByteBuf extends WrappedByteBuf {
 
     @Override
     public ByteBuf slice() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return new AdvancedLeakAwareByteBuf(super.slice(), leak);
     }
 
     @Override
     public ByteBuf slice(int index, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return new AdvancedLeakAwareByteBuf(super.slice(index, length), leak);
     }
 
     @Override
     public ByteBuf duplicate() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return new AdvancedLeakAwareByteBuf(super.duplicate(), leak);
     }
 
     @Override
     public ByteBuf readSlice(int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return new AdvancedLeakAwareByteBuf(super.readSlice(length), leak);
     }
 
     @Override
     public ByteBuf discardReadBytes() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.discardReadBytes();
     }
 
     @Override
     public ByteBuf discardSomeReadBytes() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.discardSomeReadBytes();
     }
 
     @Override
     public ByteBuf ensureWritable(int minWritableBytes) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.ensureWritable(minWritableBytes);
     }
 
     @Override
     public int ensureWritable(int minWritableBytes, boolean force) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.ensureWritable(minWritableBytes, force);
     }
 
     @Override
     public boolean getBoolean(int index) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getBoolean(index);
     }
 
     @Override
     public byte getByte(int index) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getByte(index);
     }
 
     @Override
     public short getUnsignedByte(int index) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getUnsignedByte(index);
     }
 
     @Override
     public short getShort(int index) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getShort(index);
     }
 
     @Override
     public int getUnsignedShort(int index) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getUnsignedShort(index);
     }
 
     @Override
     public int getMedium(int index) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getMedium(index);
     }
 
     @Override
     public int getUnsignedMedium(int index) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getUnsignedMedium(index);
     }
 
     @Override
     public int getInt(int index) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getInt(index);
     }
 
     @Override
     public long getUnsignedInt(int index) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getUnsignedInt(index);
     }
 
     @Override
     public long getLong(int index) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getLong(index);
     }
 
     @Override
     public char getChar(int index) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getChar(index);
     }
 
     @Override
     public float getFloat(int index) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getFloat(index);
     }
 
     @Override
     public double getDouble(int index) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getDouble(index);
     }
 
     @Override
     public ByteBuf getBytes(int index, ByteBuf dst) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getBytes(index, dst);
     }
 
     @Override
     public ByteBuf getBytes(int index, ByteBuf dst, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getBytes(index, dst, length);
     }
 
     @Override
     public ByteBuf getBytes(int index, ByteBuf dst, int dstIndex, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getBytes(index, dst, dstIndex, length);
     }
 
     @Override
     public ByteBuf getBytes(int index, byte[] dst) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getBytes(index, dst);
     }
 
     @Override
     public ByteBuf getBytes(int index, byte[] dst, int dstIndex, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getBytes(index, dst, dstIndex, length);
     }
 
     @Override
     public ByteBuf getBytes(int index, ByteBuffer dst) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getBytes(index, dst);
     }
 
     @Override
     public ByteBuf getBytes(int index, OutputStream out, int length) throws IOException {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getBytes(index, out, length);
     }
 
     @Override
     public int getBytes(int index, GatheringByteChannel out, int length) throws IOException {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.getBytes(index, out, length);
     }
 
     @Override
     public ByteBuf setBoolean(int index, boolean value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setBoolean(index, value);
     }
 
     @Override
     public ByteBuf setByte(int index, int value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setByte(index, value);
     }
 
     @Override
     public ByteBuf setShort(int index, int value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setShort(index, value);
     }
 
     @Override
     public ByteBuf setMedium(int index, int value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setMedium(index, value);
     }
 
     @Override
     public ByteBuf setInt(int index, int value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setInt(index, value);
     }
 
     @Override
     public ByteBuf setLong(int index, long value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setLong(index, value);
     }
 
     @Override
     public ByteBuf setChar(int index, int value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setChar(index, value);
     }
 
     @Override
     public ByteBuf setFloat(int index, float value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setFloat(index, value);
     }
 
     @Override
     public ByteBuf setDouble(int index, double value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setDouble(index, value);
     }
 
     @Override
     public ByteBuf setBytes(int index, ByteBuf src) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setBytes(index, src);
     }
 
     @Override
     public ByteBuf setBytes(int index, ByteBuf src, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setBytes(index, src, length);
     }
 
     @Override
     public ByteBuf setBytes(int index, ByteBuf src, int srcIndex, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setBytes(index, src, srcIndex, length);
     }
 
     @Override
     public ByteBuf setBytes(int index, byte[] src) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setBytes(index, src);
     }
 
     @Override
     public ByteBuf setBytes(int index, byte[] src, int srcIndex, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setBytes(index, src, srcIndex, length);
     }
 
     @Override
     public ByteBuf setBytes(int index, ByteBuffer src) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setBytes(index, src);
     }
 
     @Override
     public int setBytes(int index, InputStream in, int length) throws IOException {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setBytes(index, in, length);
     }
 
     @Override
     public int setBytes(int index, ScatteringByteChannel in, int length) throws IOException {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setBytes(index, in, length);
     }
 
     @Override
     public ByteBuf setZero(int index, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.setZero(index, length);
     }
 
     @Override
     public boolean readBoolean() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readBoolean();
     }
 
     @Override
     public byte readByte() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readByte();
     }
 
     @Override
     public short readUnsignedByte() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readUnsignedByte();
     }
 
     @Override
     public short readShort() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readShort();
     }
 
     @Override
     public int readUnsignedShort() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readUnsignedShort();
     }
 
     @Override
     public int readMedium() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readMedium();
     }
 
     @Override
     public int readUnsignedMedium() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readUnsignedMedium();
     }
 
     @Override
     public int readInt() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readInt();
     }
 
     @Override
     public long readUnsignedInt() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readUnsignedInt();
     }
 
     @Override
     public long readLong() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readLong();
     }
 
     @Override
     public char readChar() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readChar();
     }
 
     @Override
     public float readFloat() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readFloat();
     }
 
     @Override
     public double readDouble() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readDouble();
     }
 
     @Override
     public ByteBuf readBytes(int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readBytes(length);
     }
 
     @Override
     public ByteBuf readBytes(ByteBuf dst) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readBytes(dst);
     }
 
     @Override
     public ByteBuf readBytes(ByteBuf dst, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readBytes(dst, length);
     }
 
     @Override
     public ByteBuf readBytes(ByteBuf dst, int dstIndex, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readBytes(dst, dstIndex, length);
     }
 
     @Override
     public ByteBuf readBytes(byte[] dst) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readBytes(dst);
     }
 
     @Override
     public ByteBuf readBytes(byte[] dst, int dstIndex, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readBytes(dst, dstIndex, length);
     }
 
     @Override
     public ByteBuf readBytes(ByteBuffer dst) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readBytes(dst);
     }
 
     @Override
     public ByteBuf readBytes(OutputStream out, int length) throws IOException {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readBytes(out, length);
     }
 
     @Override
     public int readBytes(GatheringByteChannel out, int length) throws IOException {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.readBytes(out, length);
     }
 
     @Override
     public ByteBuf skipBytes(int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.skipBytes(length);
     }
 
     @Override
     public ByteBuf writeBoolean(boolean value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeBoolean(value);
     }
 
     @Override
     public ByteBuf writeByte(int value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeByte(value);
     }
 
     @Override
     public ByteBuf writeShort(int value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeShort(value);
     }
 
     @Override
     public ByteBuf writeMedium(int value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeMedium(value);
     }
 
     @Override
     public ByteBuf writeInt(int value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeInt(value);
     }
 
     @Override
     public ByteBuf writeLong(long value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeLong(value);
     }
 
     @Override
     public ByteBuf writeChar(int value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeChar(value);
     }
 
     @Override
     public ByteBuf writeFloat(float value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeFloat(value);
     }
 
     @Override
     public ByteBuf writeDouble(double value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeDouble(value);
     }
 
     @Override
     public ByteBuf writeBytes(ByteBuf src) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeBytes(src);
     }
 
     @Override
     public ByteBuf writeBytes(ByteBuf src, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeBytes(src, length);
     }
 
     @Override
     public ByteBuf writeBytes(ByteBuf src, int srcIndex, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeBytes(src, srcIndex, length);
     }
 
     @Override
     public ByteBuf writeBytes(byte[] src) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeBytes(src);
     }
 
     @Override
     public ByteBuf writeBytes(byte[] src, int srcIndex, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeBytes(src, srcIndex, length);
     }
 
     @Override
     public ByteBuf writeBytes(ByteBuffer src) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeBytes(src);
     }
 
     @Override
     public int writeBytes(InputStream in, int length) throws IOException {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeBytes(in, length);
     }
 
     @Override
     public int writeBytes(ScatteringByteChannel in, int length) throws IOException {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeBytes(in, length);
     }
 
     @Override
     public ByteBuf writeZero(int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.writeZero(length);
     }
 
     @Override
     public int indexOf(int fromIndex, int toIndex, byte value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.indexOf(fromIndex, toIndex, value);
     }
 
     @Override
     public int bytesBefore(byte value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.bytesBefore(value);
     }
 
     @Override
     public int bytesBefore(int length, byte value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.bytesBefore(length, value);
     }
 
     @Override
     public int bytesBefore(int index, int length, byte value) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.bytesBefore(index, length, value);
     }
 
     @Override
     public int forEachByte(ByteBufProcessor processor) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.forEachByte(processor);
     }
 
     @Override
     public int forEachByte(int index, int length, ByteBufProcessor processor) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.forEachByte(index, length, processor);
     }
 
     @Override
     public int forEachByteDesc(ByteBufProcessor processor) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.forEachByteDesc(processor);
     }
 
     @Override
     public int forEachByteDesc(int index, int length, ByteBufProcessor processor) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.forEachByteDesc(index, length, processor);
     }
 
     @Override
     public ByteBuf copy() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.copy();
     }
 
     @Override
     public ByteBuf copy(int index, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.copy(index, length);
     }
 
     @Override
     public int nioBufferCount() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.nioBufferCount();
     }
 
     @Override
     public ByteBuffer nioBuffer() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.nioBuffer();
     }
 
     @Override
     public ByteBuffer nioBuffer(int index, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.nioBuffer(index, length);
     }
 
     @Override
     public ByteBuffer[] nioBuffers() {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.nioBuffers();
     }
 
     @Override
     public ByteBuffer[] nioBuffers(int index, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.nioBuffers(index, length);
     }
 
     @Override
     public ByteBuffer internalNioBuffer(int index, int length) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.internalNioBuffer(index, length);
     }
 
     @Override
     public String toString(Charset charset) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.toString(charset);
     }
 
     @Override
     public String toString(int index, int length, Charset charset) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.toString(index, length, charset);
     }
 
@@ -718,7 +732,7 @@ final class AdvancedLeakAwareByteBuf extends WrappedByteBuf {
 
     @Override
     public ByteBuf capacity(int newCapacity) {
-        leak.record();
+        recordLeakNonRefCountingOperation();
         return super.capacity(newCapacity);
     }
 }

common/src/main/java/io/netty/util/ResourceLeakDetector.java

@@ -33,9 +33,14 @@ import static io.netty.util.internal.StringUtil.*;
 
 public final class ResourceLeakDetector<T> {
 
-    private static final String PROP_LEVEL = "io.netty.leakDetectionLevel";
+    private static final String PROP_LEVEL_OLD = "io.netty.leakDetectionLevel";
+    private static final String PROP_LEVEL = "io.netty.leakDetection.level";
     private static final Level DEFAULT_LEVEL = Level.SIMPLE;
 
+    private static final String PROP_MAX_RECORDS = "io.netty.leakDetection.maxRecords";
+    private static final int DEFAULT_MAX_RECORDS = 4;
+    private static final int MAX_RECORDS;
+
     /**
      * Represents the level of resource leak detection.
      */
@@ -78,7 +83,12 @@ public final class ResourceLeakDetector<T> {
         }
 
         Level defaultLevel = disabled? Level.DISABLED : DEFAULT_LEVEL;
-        String levelStr = SystemPropertyUtil.get(PROP_LEVEL, defaultLevel.name()).trim().toUpperCase();
+
+        // First read old property name
+        String levelStr = SystemPropertyUtil.get(PROP_LEVEL_OLD, defaultLevel.name()).trim().toUpperCase();
+
+        // If new property name is present, use it
+        levelStr = SystemPropertyUtil.get(PROP_LEVEL, levelStr).trim().toUpperCase();
         Level level = DEFAULT_LEVEL;
         for (Level l: EnumSet.allOf(Level.class)) {
             if (levelStr.equals(l.name()) || levelStr.equals(String.valueOf(l.ordinal()))) {
@@ -86,9 +96,12 @@ public final class ResourceLeakDetector<T> {
             }
         }
 
+        MAX_RECORDS = SystemPropertyUtil.getInt(PROP_MAX_RECORDS, DEFAULT_MAX_RECORDS);
+
         ResourceLeakDetector.level = level;
         if (logger.isDebugEnabled()) {
             logger.debug("-D{}: {}", PROP_LEVEL, level.name().toLowerCase());
+            logger.debug("-D{}: {}", PROP_MAX_RECORDS, MAX_RECORDS);
         }
     }
 
@@ -252,9 +265,6 @@ public final class ResourceLeakDetector<T> {
     }
 
     private final class DefaultResourceLeak extends PhantomReference<Object> implements ResourceLeak {
-
-        private static final int MAX_RECORDS = 4;
-
         private final String creationRecord;
         private final Deque<String> lastRecords = new ArrayDeque<String>();
         private final AtomicBoolean freed;
@@ -357,6 +367,7 @@ public final class ResourceLeakDetector<T> {
 
     private static final String[] STACK_TRACE_ELEMENT_EXCLUSIONS = {
             "io.netty.buffer.AbstractByteBufAllocator.toLeakAwareBuffer(",
+            "io.netty.buffer.AdvancedLeakAwareByteBuf.recordLeakNonRefCountingOperation("
     };
 
     static String newRecord(int recordsToSkip) {