From fc6fa2774e325da6076494ca3f23f9ea993c16ab Mon Sep 17 00:00:00 2001
From: Vladimir Schafer <vladimir.schafer@gmail.com>
Date: Thu, 6 Feb 2014 20:41:38 +0200
Subject: [PATCH] #2183 Fix for releasing of the internal cumulation buffer in
 ByteToMessageDecoder

---
 .../handler/codec/ByteToMessageDecoder.java   |  2 +
 .../codec/ByteToMessageDecoderTest.java       | 47 +++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/codec/src/main/java/io/netty/handler/codec/ByteToMessageDecoder.java b/codec/src/main/java/io/netty/handler/codec/ByteToMessageDecoder.java
index 50dc125886..637f4cd9d0 100644
--- a/codec/src/main/java/io/netty/handler/codec/ByteToMessageDecoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/ByteToMessageDecoder.java
@@ -109,6 +109,8 @@ public abstract class ByteToMessageDecoder extends ChannelHandlerAdapter {
             ByteBuf bytes = buf.readBytes(readable);
             buf.release();
             ctx.fireChannelRead(bytes);
+        } else {
+            buf.release();
         }
         cumulation = null;
         ctx.fireChannelReadComplete();
diff --git a/codec/src/test/java/io/netty/handler/codec/ByteToMessageDecoderTest.java b/codec/src/test/java/io/netty/handler/codec/ByteToMessageDecoderTest.java
index 09d5020073..bd3b343165 100644
--- a/codec/src/test/java/io/netty/handler/codec/ByteToMessageDecoderTest.java
+++ b/codec/src/test/java/io/netty/handler/codec/ByteToMessageDecoderTest.java
@@ -19,6 +19,7 @@ import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.util.ReferenceCountUtil;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -72,4 +73,50 @@ public class ByteToMessageDecoderTest {
         buf.release();
         b.release();
     }
+
+    /**
+     * Verifies that internal buffer of the ByteToMessageDecoder is released once decoder is removed from pipeline. In
+     * this case input is read fully.
+     */
+    @Test
+    public void testInternalBufferClearReadAll() {
+        final ByteBuf buf = ReferenceCountUtil.releaseLater(Unpooled.buffer().writeBytes(new byte[]{'a'}));
+        EmbeddedChannel channel = new EmbeddedChannel(new ByteToMessageDecoder() {
+            @Override
+            protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
+                ByteBuf byteBuf = internalBuffer();
+                Assert.assertEquals(1, byteBuf.refCnt());
+                in.readByte();
+                // Removal from pipeline should clear internal buffer
+                ctx.pipeline().remove(this);
+                Assert.assertEquals(0, byteBuf.refCnt());
+            }
+        });
+        Assert.assertFalse(channel.writeInbound(buf));
+        Assert.assertFalse(channel.finish());
+    }
+
+    /**
+     * Verifies that internal buffer of the ByteToMessageDecoder is released once decoder is removed from pipeline. In
+     * this case input was not fully read.
+     */
+    @Test
+    public void testInternalBufferClearReadPartly() {
+        final ByteBuf buf = ReferenceCountUtil.releaseLater(Unpooled.buffer().writeBytes(new byte[]{'a', 'b'}));
+        EmbeddedChannel channel = new EmbeddedChannel(new ByteToMessageDecoder() {
+            @Override
+            protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
+                ByteBuf byteBuf = internalBuffer();
+                Assert.assertEquals(1, byteBuf.refCnt());
+                in.readByte();
+                // Removal from pipeline should clear internal buffer
+                ctx.pipeline().remove(this);
+                Assert.assertEquals(0, byteBuf.refCnt());
+            }
+        });
+        Assert.assertTrue(channel.writeInbound(buf));
+        Assert.assertTrue(channel.finish());
+        Assert.assertEquals(channel.readInbound(), Unpooled.wrappedBuffer(new byte[] {'b'}));
+        Assert.assertNull(channel.readInbound());
+    }
 }