From ae7e43139dda16c501f6d7606f04d631e0a23c3e Mon Sep 17 00:00:00 2001
From: Devaraj Das <ddas@apache.org>
Date: Tue, 21 Feb 2012 05:19:53 +0000
Subject: [PATCH] HADOOP-8084. Updates ProtoBufRpc engine to not do an
 unnecessary copy for RPC request/response. Contributed by Devaraj Das.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1291602 13f79535-47bb-0310-9956-ffa450edef68
---
 hadoop-common-project/hadoop-common/CHANGES.txt    |  3 +++
 .../org/apache/hadoop/ipc/ProtobufRpcEngine.java   | 14 ++++++++------
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index cbc39e5d74..a4ee873802 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -86,6 +86,9 @@ Trunk (unreleased changes)
 
     HADOOP-8070. Add a standalone benchmark for RPC call performance. (todd)
 
+    HADOOP-8084. Updates ProtoBufRpc engine to not do an unnecessary copy 
+    for RPC request/response. (ddas)
+
   BUG FIXES
 
     HADOOP-8018.  Hudson auto test for HDFS has started throwing javadoc
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/ProtobufRpcEngine.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/ProtobufRpcEngine.java
index 9b3862abdb..9a1a1615b0 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/ProtobufRpcEngine.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/ProtobufRpcEngine.java
@@ -34,6 +34,7 @@
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.io.DataOutputOutputStream;
 import org.apache.hadoop.io.Writable;
 import org.apache.hadoop.ipc.Client.ConnectionId;
 import org.apache.hadoop.ipc.RPC.RpcInvoker;
@@ -45,6 +46,7 @@
 import org.apache.hadoop.security.UserGroupInformation;
 import org.apache.hadoop.security.token.SecretManager;
 import org.apache.hadoop.security.token.TokenIdentifier;
+import org.apache.hadoop.util.ProtoUtil;
 import org.apache.hadoop.util.StringUtils;
 
 import com.google.common.annotations.VisibleForTesting;
@@ -268,13 +270,13 @@ public RpcRequestWritable() {
 
     @Override
     public void write(DataOutput out) throws IOException {
-      out.writeInt(message.toByteArray().length);
-      out.write(message.toByteArray());
+      ((Message)message).writeDelimitedTo(
+          DataOutputOutputStream.constructOutputStream(out));
     }
 
     @Override
     public void readFields(DataInput in) throws IOException {
-      int length = in.readInt();
+      int length = ProtoUtil.readRawVarint32(in);
       byte[] bytes = new byte[length];
       in.readFully(bytes);
       message = HadoopRpcRequestProto.parseFrom(bytes);
@@ -297,13 +299,13 @@ public RpcResponseWritable(HadoopRpcResponseProto message) {
 
     @Override
     public void write(DataOutput out) throws IOException {
-      out.writeInt(message.toByteArray().length);
-      out.write(message.toByteArray());
+      ((Message)message).writeDelimitedTo(
+          DataOutputOutputStream.constructOutputStream(out));      
     }
 
     @Override
     public void readFields(DataInput in) throws IOException {
-      int length = in.readInt();
+      int length = ProtoUtil.readRawVarint32(in);
       byte[] bytes = new byte[length];
       in.readFully(bytes);
       message = HadoopRpcResponseProto.parseFrom(bytes);