From 52cb7a7413a33a86079cf8e9b3561e33339aeb9d Mon Sep 17 00:00:00 2001
From: David Reiss <dreiss@apache.org>
Date: Mon, 30 Jun 2008 21:40:35 +0000
Subject: [PATCH] (THRIFT-45) TNonblockingServer (C++): only do one write in
 responses.

Instead of doing one 4-byte write for the frame length before the write
of the actual message, prepend the frame length to the message buffer
so we can send them both at once.


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@672937 13f79535-47bb-0310-9956-ffa450edef68
---
 lib/cpp/src/server/TNonblockingServer.cpp | 30 +++++++----------------
 lib/cpp/src/server/TNonblockingServer.h   |  4 ---
 2 files changed, 9 insertions(+), 25 deletions(-)

diff --git a/lib/cpp/src/server/TNonblockingServer.cpp b/lib/cpp/src/server/TNonblockingServer.cpp
index e376f971..cd7951d3 100644
--- a/lib/cpp/src/server/TNonblockingServer.cpp
+++ b/lib/cpp/src/server/TNonblockingServer.cpp
@@ -220,6 +220,10 @@ void TConnection::transition() {
     // and get back some data from the dispatch function
     inputTransport_->resetBuffer(readBuffer_, readBufferPos_);
     outputTransport_->resetBuffer();
+    // Prepend four bytes of blank space to the buffer so we can
+    // write the frame size there later.
+    outputTransport_->getWritePtr(4);
+    outputTransport_->wroteBytes(4);
 
     if (server_->isThreadPoolProcessing()) {
       // We are setting up a Task to do this work and we will wait on it
@@ -293,7 +297,7 @@ void TConnection::transition() {
 
     // If the function call generated return data, then move into the send
     // state and get going
-    if (writeBufferSize_ > 0) {
+    if (writeBufferSize_ > 4) {
 
       // Move into write state
       writeBufferPos_ = 0;
@@ -301,16 +305,15 @@ void TConnection::transition() {
 
       if (server_->getFrameResponses()) {
         // Put the frame size into the write buffer
-        appState_ = APP_SEND_FRAME_SIZE;
-        frameSize_ = (int32_t)htonl(writeBufferSize_);
-        writeBuffer_ = (uint8_t*)&frameSize_;
-        writeBufferSize_ = 4;
+        int32_t frameSize = (int32_t)htonl(writeBufferSize_ - 4);
+        memcpy(writeBuffer_, &frameSize, 4);
       } else {
         // Go straight into sending the result, do not frame it
-        appState_ = APP_SEND_RESULT;
+        writeBufferPos_ = 4;
       }
 
       // Socket into write mode
+      appState_ = APP_SEND_RESULT;
       setWrite();
 
       // Try to work the socket immediately
@@ -323,21 +326,6 @@ void TConnection::transition() {
     // right back into the read frame header state
     goto LABEL_APP_INIT;
 
-  case APP_SEND_FRAME_SIZE:
-
-    // Refetch the result of the operation since we put the frame size into
-    // writeBuffer_
-    outputTransport_->getBuffer(&writeBuffer_, &writeBufferSize_);
-    writeBufferPos_ = 0;
-
-    // Now in send result state
-    appState_ = APP_SEND_RESULT;
-
-    // Go to work on the socket right away, probably still writeable
-    // workSocket();
-
-    return;
-
   case APP_SEND_RESULT:
 
     // N.B.: We also intentionally fall through here into the INIT state!
diff --git a/lib/cpp/src/server/TNonblockingServer.h b/lib/cpp/src/server/TNonblockingServer.h
index 3de5b948..9d426fa9 100644
--- a/lib/cpp/src/server/TNonblockingServer.h
+++ b/lib/cpp/src/server/TNonblockingServer.h
@@ -211,7 +211,6 @@ enum TAppState {
   APP_READ_FRAME_SIZE,
   APP_READ_REQUEST,
   APP_WAIT_TASK,
-  APP_SEND_FRAME_SIZE,
   APP_SEND_RESULT
 };
 
@@ -263,9 +262,6 @@ class TConnection {
   // How far through writing are we?
   uint32_t writeBufferPos_;
 
-  // Frame size
-  int32_t frameSize_;
-
   // Task handle
   int taskHandle_;
 
-- 
2.17.1