QProcess: Ensure that the stdin buffer is cleared on start()

The buffer may have been left dirty if we were unable to write all the
data to the child process in the previous run. So ensure we clear it
before starting a new one. We already did that for stdout and stderr,
for some reason.

Task-number: QTBUG-44517
Change-Id: I1a800c709d3543699131ffff13c419da3bbffacf
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@theqtcompany.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>

2 files changed, 3 insertions, 2 deletions

diff --git a/src/corelib/io/qprocess.cpp b/src/corelib/io/qprocess.cpp
index 176386d6df..c29b97b535 100644
--- a/src/corelib/io/qprocess.cpp
+++ b/src/corelib/io/qprocess.cpp
@@ -1,7 +1,7 @@
 /****************************************************************************
 **
 ** Copyright (C) 2015 The Qt Company Ltd.
-** Copyright (C) 2014 Intel Corporation
+** Copyright (C) 2015 Intel Corporation
 ** Contact: http://www.qt.io/licensing/
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
@@ -2135,6 +2135,7 @@ void QProcessPrivate::start(QIODevice::OpenMode mode)
     qDebug() << "QProcess::start(" << program << ',' << arguments << ',' << mode << ')';
 #endif
 
+    stdinChannel.buffer.clear();
     stdoutChannel.buffer.clear();
     stderrChannel.buffer.clear();
 
diff --git a/src/corelib/io/qwindowspipewriter.cpp b/src/corelib/io/qwindowspipewriter.cpp
index add2ac94da..57053f129a 100644
--- a/src/corelib/io/qwindowspipewriter.cpp
+++ b/src/corelib/io/qwindowspipewriter.cpp
@@ -85,7 +85,7 @@ qint64 QWindowsPipeWriter::write(const char *ptr, qint64 maxlen)
         return -1;
 
     QMutexLocker locker(&lock);
-    data.append(QByteArray(ptr, maxlen));
+    data.append(ptr, maxlen);
     waitCondition.wakeOne();
     return maxlen;
 }