From c462ec960bc7790c664aae5c6bbb2d3b57ec8b94 Mon Sep 17 00:00:00 2001
From: Norman Maurer <norman_maurer@apple.com>
Date: Wed, 16 Oct 2019 06:47:59 -0700
Subject: [PATCH] Eliminate unnessary copy of ByteBuf on ByteToMessageDecoder
 removal (#9662)

Motivation:

At the moment we do a ByteBuf.readBytes(...) on removal of the ByteToMessageDecoder if there are any bytes left and forward the returned ByteBuf to the next handler in the pipeline. This is not really needed as we can just forward the cumulation buffer directly and so eliminate the extra memory copy

Modifications:

Just forward the cumulation buffer directly on removal of the ByteToMessageDecoder

Result:

Less memory copies
---
 .../java/io/netty/handler/codec/ByteToMessageDecoder.java     | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

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 b36186f8c9..6014bca470 100644
--- a/codec/src/main/java/io/netty/handler/codec/ByteToMessageDecoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/ByteToMessageDecoder.java
@@ -245,9 +245,7 @@ public abstract class ByteToMessageDecoder extends ChannelHandlerAdapter impleme
             numReads = 0;
             int readable = buf.readableBytes();
             if (readable > 0) {
-                ByteBuf bytes = buf.readBytes(readable);
-                buf.release();
-                ctx.fireChannelRead(bytes);
+                ctx.fireChannelRead(buf);
                 ctx.fireChannelReadComplete();
             } else {
                 buf.release();