From 936e5ae1a8bfac4679ade6049aed80ea08de06df Mon Sep 17 00:00:00 2001
From: norman <norman@apache.org>
Date: Fri, 2 Dec 2011 07:22:14 +0100
Subject: [PATCH] Make sure the cumulation Buffer is only created if really
 needed. See #88

---
 .../handler/codec/frame/FrameDecoder.java     | 29 +++++++++++++++----
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/src/main/java/org/jboss/netty/handler/codec/frame/FrameDecoder.java b/src/main/java/org/jboss/netty/handler/codec/frame/FrameDecoder.java
index a3e173d168..aebd01ca68 100644
--- a/src/main/java/org/jboss/netty/handler/codec/frame/FrameDecoder.java
+++ b/src/main/java/org/jboss/netty/handler/codec/frame/FrameDecoder.java
@@ -207,17 +207,28 @@ public abstract class FrameDecoder extends SimpleChannelUpstreamHandler {
             return;
         }
 
-        ChannelBuffer cumulation = cumulation(ctx);
-        if (cumulation.readable()) {
-            cumulation.discardReadBytes();
-            cumulation.writeBytes(input);
-            callDecode(ctx, e.getChannel(), cumulation, e.getRemoteAddress());
-        } else {
+        if (cumulation == null) {
+            // the cumulation buffer is not created yet so just pass the input to callDecode(...) method
             callDecode(ctx, e.getChannel(), input, e.getRemoteAddress());
             if (input.readable()) {
+                // seems like there is something readable left in the input buffer. So create the cumulation buffer and copy the input into it
+                ChannelBuffer cumulation = cumulation(ctx);
                 cumulation.writeBytes(input);
             }
+        } else {
+            ChannelBuffer cumulation = cumulation(ctx);
+            if (cumulation.readable()) {
+                cumulation.discardReadBytes();
+                cumulation.writeBytes(input);
+                callDecode(ctx, e.getChannel(), cumulation, e.getRemoteAddress());
+            } else {
+                callDecode(ctx, e.getChannel(), input, e.getRemoteAddress());
+                if (input.readable()) {
+                    cumulation.writeBytes(input);
+                }
+            }
         }
+        
     }
 
     @Override
@@ -349,6 +360,12 @@ public abstract class FrameDecoder extends SimpleChannelUpstreamHandler {
         }
     }
 
+    /**
+     * Get the currently used {@link ChannelBuffer} for cumulation or create one in a lazy fashion if none exist yet
+     * 
+     * @param ctx the {@link ChannelHandlerContext} for this handler
+     * @return buffer the {@link ChannelBuffer} which is used fo cumulation
+     */
     private ChannelBuffer cumulation(ChannelHandlerContext ctx) {
         ChannelBuffer c = cumulation;
         if (c == null) {