From 33d3c2d9ae50b3c6142ccfd09b82ed0cbba607ab Mon Sep 17 00:00:00 2001
From: Qingning Huo <qingninghuo@gmail.com>
Date: Sat, 4 Feb 2012 20:30:01 +0000
Subject: Avoid using undefined value in Subprocess::OnPipeReady()

---
 src/subprocess-win32.cc | 5 +++--
 src/subprocess.h        | 1 +
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/subprocess-win32.cc b/src/subprocess-win32.cc
index e757f7e..c0185e4 100644
--- a/src/subprocess-win32.cc
+++ b/src/subprocess-win32.cc
@@ -28,7 +28,7 @@ void Win32Fatal(const char* function) {
 
 }  // anonymous namespace
 
-Subprocess::Subprocess() : child_(NULL) , overlapped_() {
+Subprocess::Subprocess() : child_(NULL) , overlapped_(), is_reading_(false) {
 }
 
 Subprocess::~Subprocess() {
@@ -130,10 +130,11 @@ void Subprocess::OnPipeReady() {
     Win32Fatal("GetOverlappedResult");
   }
 
-  if (bytes)
+  if (is_reading_ && bytes)
     buf_.append(overlapped_buf_, bytes);
 
   memset(&overlapped_, 0, sizeof(overlapped_));
+  is_reading_ = true;
   if (!::ReadFile(pipe_, overlapped_buf_, sizeof(overlapped_buf_),
                   &bytes, &overlapped_)) {
     if (GetLastError() == ERROR_BROKEN_PIPE) {
diff --git a/src/subprocess.h b/src/subprocess.h
index 9828bf4..f355944 100644
--- a/src/subprocess.h
+++ b/src/subprocess.h
@@ -52,6 +52,7 @@ struct Subprocess {
   HANDLE pipe_;
   OVERLAPPED overlapped_;
   char overlapped_buf_[4 << 10];
+  bool is_reading_;
 #else
   int fd_;
   pid_t pid_;
-- 
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