Move ReferenceCounted and AbstractReferenceCounted to io.netty.util

- Fixes #1441
- Also move and rename IllegalBufferAccessException to ReferenceCountException
- Prettier reference count exception messages

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

@@ -15,6 +15,7 @@
  */
 package io.netty.buffer;
 
+import io.netty.util.ReferenceCountException;
 import io.netty.util.ResourceLeakDetector;
 
 import java.io.IOException;
@@ -1133,7 +1134,7 @@ public abstract class AbstractByteBuf implements ByteBuf {
      */
     protected final void ensureAccessible() {
         if (refCnt() == 0) {
-            throw new IllegalBufferAccessException();
+            throw new ReferenceCountException(0);
         }
     }
 }

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

@@ -16,6 +16,7 @@
 
 package io.netty.buffer;
 
+import io.netty.util.ReferenceCountException;
 import io.netty.util.internal.PlatformDependent;
 
 import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
@@ -73,10 +74,10 @@ public abstract class AbstractReferenceCountedByteBuf extends AbstractByteBuf {
         for (;;) {
             int refCnt = this.refCnt;
             if (refCnt == 0) {
-                throw new IllegalBufferAccessException();
+                throw new ReferenceCountException(0, 1);
             }
             if (refCnt == Integer.MAX_VALUE) {
-                throw new IllegalBufferAccessException("refCnt overflow");
+                throw new ReferenceCountException(Integer.MAX_VALUE, 1);
             }
             if (refCntUpdater.compareAndSet(this, refCnt, refCnt + 1)) {
                 break;
@@ -94,10 +95,10 @@ public abstract class AbstractReferenceCountedByteBuf extends AbstractByteBuf {
         for (;;) {
             int refCnt = this.refCnt;
             if (refCnt == 0) {
-                throw new IllegalBufferAccessException();
+                throw new ReferenceCountException(0, increment);
             }
             if (refCnt > Integer.MAX_VALUE - increment) {
-                throw new IllegalBufferAccessException("refCnt overflow");
+                throw new ReferenceCountException(refCnt, increment);
             }
             if (refCntUpdater.compareAndSet(this, refCnt, refCnt + increment)) {
                 break;
@@ -111,7 +112,7 @@ public abstract class AbstractReferenceCountedByteBuf extends AbstractByteBuf {
         for (;;) {
             int refCnt = this.refCnt;
             if (refCnt == 0) {
-                throw new IllegalBufferAccessException();
+                throw new ReferenceCountException(0, -1);
             }
 
             if (refCntUpdater.compareAndSet(this, refCnt, refCnt - 1)) {
@@ -133,7 +134,7 @@ public abstract class AbstractReferenceCountedByteBuf extends AbstractByteBuf {
         for (;;) {
             int refCnt = this.refCnt;
             if (refCnt < decrement) {
-                throw new IllegalBufferAccessException();
+                throw new ReferenceCountException(refCnt, -decrement);
             }
 
             if (refCntUpdater.compareAndSet(this, refCnt, refCnt - decrement)) {

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

@@ -15,6 +15,8 @@
  */
 package io.netty.buffer;
 
+import io.netty.util.ReferenceCounted;
+
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;

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

@@ -15,6 +15,8 @@
  */
 package io.netty.buffer;
 
+import io.netty.util.ReferenceCounted;
+
 /**
  * A packet which is send or receive.
  */

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

@@ -16,6 +16,7 @@
 package io.netty.buffer;
 
 import io.netty.util.CharsetUtil;
+import io.netty.util.ReferenceCounted;
 
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;

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

@@ -15,6 +15,8 @@
  */
 package io.netty.buffer;
 
+import io.netty.util.ReferenceCountException;
+
 /**
  * Default implementation of a {@link ByteBufHolder} that holds it's data in a {@link ByteBuf}.
  *
@@ -33,7 +35,7 @@ public class DefaultByteBufHolder implements ByteBufHolder {
     @Override
     public ByteBuf content() {
         if (data.refCnt() <= 0) {
-            throw new IllegalBufferAccessException();
+            throw new ReferenceCountException(data.refCnt());
         }
         return data;
     }

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

@@ -1,40 +0,0 @@
-/*
- * Copyright 2012 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-
-package io.netty.buffer;
-
-/**
- * An {@link IllegalStateException} raised when a user attempts to access a {@link Buf} which was freed by
- * {@link Buf#release()} } already.
- */
-public class IllegalBufferAccessException extends IllegalStateException {
-
-    private static final long serialVersionUID = -6734326916218551327L;
-
-    public IllegalBufferAccessException() { }
-
-    public IllegalBufferAccessException(String message) {
-        super(message);
-    }
-
-    public IllegalBufferAccessException(String message, Throwable cause) {
-        super(message, cause);
-    }
-
-    public IllegalBufferAccessException(Throwable cause) {
-        super(cause);
-    }
-}

codec-http/src/main/java/io/netty/handler/codec/http/multipart/AbstractHttpData.java

@@ -15,10 +15,10 @@
  */
 package io.netty.handler.codec.http.multipart;
 
-import io.netty.buffer.AbstractReferenceCounted;
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelException;
 import io.netty.handler.codec.http.HttpConstants;
+import io.netty.util.AbstractReferenceCounted;
 
 import java.io.IOException;
 import java.nio.charset.Charset;

codec-http/src/main/java/io/netty/handler/codec/spdy/DefaultSpdyDataFrame.java

@@ -16,8 +16,8 @@
 package io.netty.handler.codec.spdy;
 
 import io.netty.buffer.ByteBuf;
-import io.netty.buffer.IllegalBufferAccessException;
 import io.netty.buffer.Unpooled;
+import io.netty.util.ReferenceCountException;
 import io.netty.util.internal.StringUtil;
 
 /**
@@ -73,7 +73,7 @@ public class DefaultSpdyDataFrame extends DefaultSpdyStreamFrame implements Spdy
     @Override
     public ByteBuf content() {
         if (data.refCnt() <= 0) {
-            throw new IllegalBufferAccessException();
+            throw new ReferenceCountException(data.refCnt());
         }
         return data;
     }

codec/src/main/java/io/netty/handler/codec/MessageToMessageCodec.java

@@ -15,11 +15,11 @@
  */
 package io.netty.handler.codec;
 
-import io.netty.buffer.ReferenceCounted;
 import io.netty.channel.ChannelDuplexHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelPromise;
 import io.netty.channel.MessageList;
+import io.netty.util.ReferenceCounted;
 import io.netty.util.internal.TypeParameterMatcher;
 
 /**

codec/src/main/java/io/netty/handler/codec/MessageToMessageDecoder.java

@@ -16,10 +16,10 @@
 package io.netty.handler.codec;
 
 import io.netty.buffer.ByteBufUtil;
-import io.netty.buffer.ReferenceCounted;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.channel.MessageList;
+import io.netty.util.ReferenceCounted;
 import io.netty.util.internal.TypeParameterMatcher;
 
 /**

codec/src/main/java/io/netty/handler/codec/MessageToMessageEncoder.java

@@ -16,11 +16,11 @@
 package io.netty.handler.codec;
 
 import io.netty.buffer.ByteBufUtil;
-import io.netty.buffer.ReferenceCounted;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelOutboundHandlerAdapter;
 import io.netty.channel.ChannelPromise;
 import io.netty.channel.MessageList;
+import io.netty.util.ReferenceCounted;
 import io.netty.util.internal.TypeParameterMatcher;
 
 /**

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

@@ -13,7 +13,7 @@
  * License for the specific language governing permissions and limitations
  * under the License.
  */
-package io.netty.buffer;
+package io.netty.util;
 
 import io.netty.util.internal.PlatformDependent;
 
@@ -68,10 +68,10 @@ public abstract class AbstractReferenceCounted implements ReferenceCounted {
         for (;;) {
             int refCnt = this.refCnt;
             if (refCnt == 0) {
-                throw new IllegalBufferAccessException();
+                throw new ReferenceCountException(0, 1);
             }
             if (refCnt == Integer.MAX_VALUE) {
-                throw new IllegalBufferAccessException("refCnt overflow");
+                throw new ReferenceCountException(Integer.MAX_VALUE, 1);
             }
             if (refCntUpdater.compareAndSet(this, refCnt, refCnt + 1)) {
                 break;
@@ -89,10 +89,10 @@ public abstract class AbstractReferenceCounted implements ReferenceCounted {
         for (;;) {
             int refCnt = this.refCnt;
             if (refCnt == 0) {
-                throw new IllegalBufferAccessException();
+                throw new ReferenceCountException(0, 1);
             }
             if (refCnt > Integer.MAX_VALUE - increment) {
-                throw new IllegalBufferAccessException("refCnt overflow");
+                throw new ReferenceCountException(refCnt, increment);
             }
             if (refCntUpdater.compareAndSet(this, refCnt, refCnt + increment)) {
                 break;
@@ -106,7 +106,7 @@ public abstract class AbstractReferenceCounted implements ReferenceCounted {
         for (;;) {
             int refCnt = this.refCnt;
             if (refCnt == 0) {
-                throw new IllegalBufferAccessException();
+                throw new ReferenceCountException(0, -1);
             }
 
             if (refCntUpdater.compareAndSet(this, refCnt, refCnt - 1)) {
@@ -128,7 +128,7 @@ public abstract class AbstractReferenceCounted implements ReferenceCounted {
         for (;;) {
             int refCnt = this.refCnt;
             if (refCnt < decrement) {
-                throw new IllegalBufferAccessException();
+                throw new ReferenceCountException(refCnt, -decrement);
             }
 
             if (refCntUpdater.compareAndSet(this, refCnt, refCnt - decrement)) {

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

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2012 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+package io.netty.util;
+
+/**
+ * An {@link IllegalStateException} which is raised when a user attempts to access a {@link ReferenceCounted} whose
+ * reference count has been decreased to 0 (and consequently freed).
+ */
+public class ReferenceCountException extends IllegalStateException {
+
+    private static final long serialVersionUID = -2507492394288153468L;
+
+    public ReferenceCountException() { }
+
+    public ReferenceCountException(int refCnt) {
+        this("refCnt: " + refCnt);
+    }
+
+    public ReferenceCountException(int refCnt, int increment) {
+        this("refCnt: " + refCnt + ", " + (increment > 0? "increment: " + increment : "decrement: " + -increment));
+    }
+
+    public ReferenceCountException(String message) {
+        super(message);
+    }
+
+    public ReferenceCountException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public ReferenceCountException(Throwable cause) {
+        super(cause);
+    }
+}

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

@@ -13,7 +13,7 @@
  * License for the specific language governing permissions and limitations
  * under the License.
  */
-package io.netty.buffer;
+package io.netty.util;
 
 /**
  * A reference-counted object that requires explicit deallocation.
@@ -24,8 +24,9 @@ package io.netty.buffer;
  * the deallocated object will usually result in an access violation.
  * </p>
  * <p>
- * If this object is a container such as {@link MessageBuf} and {@link CompositeByteBuf}, its elements whose type is
- * {@link ReferenceCounted} will also be released when this object is deallocated.
+ * If an object that implements {@link ReferenceCounted} is a container of other objects that implement
+ * {@link ReferenceCounted}, the contained objects will also be released via {@link #release()} when the container's
+ * reference count becomes 0.
  * </p>
  */
 public interface ReferenceCounted {

transport/src/main/java/io/netty/channel/AddressedEnvelope.java

@@ -16,7 +16,7 @@
 
 package io.netty.channel;
 
-import io.netty.buffer.ReferenceCounted;
+import io.netty.util.ReferenceCounted;
 
 import java.net.SocketAddress;
 

transport/src/main/java/io/netty/channel/DefaultAddressedEnvelope.java

@@ -17,7 +17,7 @@
 package io.netty.channel;
 
 import io.netty.buffer.ByteBufUtil;
-import io.netty.buffer.ReferenceCounted;
+import io.netty.util.ReferenceCounted;
 import io.netty.util.internal.StringUtil;
 
 import java.net.SocketAddress;

transport/src/main/java/io/netty/channel/DefaultFileRegion.java

@@ -15,7 +15,7 @@
  */
 package io.netty.channel;
 
-import io.netty.buffer.AbstractReferenceCounted;
+import io.netty.util.AbstractReferenceCounted;
 import io.netty.util.internal.logging.InternalLogger;
 import io.netty.util.internal.logging.InternalLoggerFactory;
 

transport/src/main/java/io/netty/channel/FileRegion.java

@@ -15,7 +15,7 @@
  */
 package io.netty.channel;
 
-import io.netty.buffer.ReferenceCounted;
+import io.netty.util.ReferenceCounted;
 
 import java.io.IOException;
 import java.nio.channels.FileChannel;

transport/src/test/java/io/netty/channel/DefaultChannelPipelineTest.java

@@ -18,12 +18,12 @@ package io.netty.channel;
 
 import io.netty.bootstrap.Bootstrap;
 import io.netty.bootstrap.ServerBootstrap;
-import io.netty.buffer.ReferenceCounted;
 import io.netty.channel.ChannelHandler.Sharable;
 import io.netty.channel.local.LocalAddress;
 import io.netty.channel.local.LocalChannel;
 import io.netty.channel.local.LocalEventLoopGroup;
 import io.netty.channel.local.LocalServerChannel;
+import io.netty.util.ReferenceCounted;
 import org.junit.After;
 import org.junit.AfterClass;
 import org.junit.Test;