From 219b0d21747816cebf8016be6e2433394ee246c7 Mon Sep 17 00:00:00 2001
From: Joerg Bornemann <joerg.bornemann@digia.com>
Date: Thu, 27 Sep 2012 15:33:45 +0200
Subject: [PATCH] QProcess/Win fix forwarding of output channels

We must not create pipe readers for the forwarded channels as we don't
want to read from stdout/stderr into the internal QProcess buffer.
Also, we must not pass CREATE_NO_WINDOW to CreateProcess because this
will render our stdout/stderr handles useless.

Change-Id: Ie6485e86c103d1e9225cf39c04aa54093c1efe0d
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
---
 src/corelib/io/qprocess_win.cpp | 36 ++++++++++++++++++---------------
 1 file changed, 20 insertions(+), 16 deletions(-)

diff --git a/src/corelib/io/qprocess_win.cpp b/src/corelib/io/qprocess_win.cpp
index 21db37c19a..dd5cf4819e 100644
--- a/src/corelib/io/qprocess_win.cpp
+++ b/src/corelib/io/qprocess_win.cpp
@@ -160,23 +160,25 @@ bool QProcessPrivate::createChannel(Channel &channel)
         else
             duplicateStdWriteChannel(channel.pipe, (&channel == &stdoutChannel) ? STD_OUTPUT_HANDLE : STD_ERROR_HANDLE);
 
-        QWindowsPipeReader *pipeReader = 0;
-        if (&channel == &stdoutChannel) {
-            if (!stdoutReader) {
-                stdoutReader = new QWindowsPipeReader(q);
-                q->connect(stdoutReader, SIGNAL(readyRead()), SLOT(_q_canReadStandardOutput()));
+        if (processChannelMode != QProcess::ForwardedChannels) {
+            QWindowsPipeReader *pipeReader = 0;
+            if (&channel == &stdoutChannel) {
+                if (!stdoutReader) {
+                    stdoutReader = new QWindowsPipeReader(q);
+                    q->connect(stdoutReader, SIGNAL(readyRead()), SLOT(_q_canReadStandardOutput()));
+                }
+                pipeReader = stdoutReader;
+            } else if (&channel == &stderrChannel) {
+                if (!stderrReader) {
+                    stderrReader = new QWindowsPipeReader(q);
+                    q->connect(stderrReader, SIGNAL(readyRead()), SLOT(_q_canReadStandardError()));
+                }
+                pipeReader = stderrReader;
             }
-            pipeReader = stdoutReader;
-        } else if (&channel == &stderrChannel) {
-            if (!stderrReader) {
-                stderrReader = new QWindowsPipeReader(q);
-                q->connect(stderrReader, SIGNAL(readyRead()), SLOT(_q_canReadStandardError()));
+            if (pipeReader) {
+                pipeReader->setHandle(channel.pipe[0]);
+                pipeReader->startAsyncRead();
             }
-            pipeReader = stderrReader;
-        }
-        if (pipeReader) {
-            pipeReader->setHandle(channel.pipe[0]);
-            pipeReader->startAsyncRead();
         }
 
         return true;
@@ -473,7 +475,9 @@ void QProcessPrivate::startProcess()
     qDebug("   pass environment : %s", environment.isEmpty() ? "no" : "yes");
 #endif
 
-    DWORD dwCreationFlags = CREATE_NO_WINDOW;
+    // Forwarded channels must not set the CREATE_NO_WINDOW flag because this
+    // will render the stdout/stderr handles we're passing useless.
+    DWORD dwCreationFlags = (processChannelMode == QProcess::ForwardedChannels ? 0 : CREATE_NO_WINDOW);
     dwCreationFlags |= CREATE_UNICODE_ENVIRONMENT;
     STARTUPINFOW startupInfo = { sizeof( STARTUPINFO ), 0, 0, 0,
                                  (ulong)CW_USEDEFAULT, (ulong)CW_USEDEFAULT,