remove the "wonderful Windows notifier" from QProcess

Remove the 100 ms timer that was used to nudge QProcess to write data
to the child's stdin. Instead, react on the canWrite() signal of
QWindowsPipeWriter.
QProcess::writeData needs to call _q_canWrite via the event loop to
start the write operation. The socket notifier code was never in use on
Windows.

Task-number: QTBUG-45457
Change-Id: I99c956ba5f2169f80068eee206543ceb9788b2e0
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>

src/corelib/io/qprocess.cpp

@@ -36,6 +36,9 @@
 
 #include <qdebug.h>
 #include <qdir.h>
+#if defined(Q_OS_WIN)
+#include <qtimer.h>
+#endif
 #if defined QPROCESS_DEBUG
 #include <qstring.h>
 #include <ctype.h>
@@ -819,7 +822,7 @@ QProcessPrivate::QProcessPrivate()
     emittedReadyRead = false;
     emittedBytesWritten = false;
 #ifdef Q_OS_WIN
-    notifier = 0;
+    stdinWriteTrigger = 0;
     processFinishedNotifier = 0;
 #endif // Q_OS_WIN
 }
@@ -848,6 +851,10 @@ void QProcessPrivate::cleanup()
         delete pid;
         pid = 0;
     }
+    if (stdinWriteTrigger) {
+        delete stdinWriteTrigger;
+        stdinWriteTrigger = 0;
+    }
     if (processFinishedNotifier) {
         delete processFinishedNotifier;
         processFinishedNotifier = 0;
@@ -878,12 +885,6 @@ void QProcessPrivate::cleanup()
         delete deathNotifier;
         deathNotifier = 0;
     }
-#ifdef Q_OS_WIN
-    if (notifier) {
-        delete notifier;
-        notifier = 0;
-    }
-#endif
     closeChannel(&stdoutChannel);
     closeChannel(&stderrChannel);
     closeChannel(&stdinChannel);
@@ -1953,10 +1954,24 @@ qint64 QProcess::writeData(const char *data, qint64 len)
         return 0;
     }
 
+#if defined(Q_OS_WIN)
+    if (!d->stdinWriteTrigger) {
+        d->stdinWriteTrigger = new QTimer;
+        d->stdinWriteTrigger->setSingleShot(true);
+        QObjectPrivate::connect(d->stdinWriteTrigger, &QTimer::timeout,
+                                d, &QProcessPrivate::_q_canWrite);
+    }
+#endif
+
     if (len == 1) {
         d->stdinChannel.buffer.putChar(*data);
+#ifdef Q_OS_WIN
+        if (!d->stdinWriteTrigger->isActive())
+            d->stdinWriteTrigger->start();
+#else
         if (d->stdinChannel.notifier)
             d->stdinChannel.notifier->setEnabled(true);
+#endif
 #if defined QPROCESS_DEBUG
     qDebug("QProcess::writeData(%p \"%s\", %lld) == 1 (written to buffer)",
            data, qt_prettyDebug(data, len, 16).constData(), len);
@@ -1966,8 +1981,13 @@ qint64 QProcess::writeData(const char *data, qint64 len)
 
     char *dest = d->stdinChannel.buffer.reserve(len);
     memcpy(dest, data, len);
+#ifdef Q_OS_WIN
+    if (!d->stdinWriteTrigger->isActive())
+        d->stdinWriteTrigger->start();
+#else
     if (d->stdinChannel.notifier)
         d->stdinChannel.notifier->setEnabled(true);
+#endif
 #if defined QPROCESS_DEBUG
     qDebug("QProcess::writeData(%p \"%s\", %lld) == %lld (written to buffer)",
            data, qt_prettyDebug(data, len, 16).constData(), len, len);

src/corelib/io/qprocess.h

@@ -266,7 +266,6 @@ private:
     Q_PRIVATE_SLOT(d_func(), bool _q_canWrite())
     Q_PRIVATE_SLOT(d_func(), bool _q_startupNotification())
     Q_PRIVATE_SLOT(d_func(), bool _q_processDied())
-    Q_PRIVATE_SLOT(d_func(), void _q_notified())
     friend class QProcessManager;
 };
 

src/corelib/io/qprocess_p.h

@@ -303,7 +303,6 @@ public:
     bool _q_canWrite();
     bool _q_startupNotification();
     bool _q_processDied();
-    void _q_notified();
 
     QProcess::ProcessChannel processChannel;
     QProcess::ProcessChannelMode processChannelMode;
@@ -342,8 +341,7 @@ public:
     int forkfd;
 
 #ifdef Q_OS_WIN
-    // the wonderful windows notifier
-    QTimer *notifier;
+    QTimer *stdinWriteTrigger;
     QWinEventNotifier *processFinishedNotifier;
 #endif
 

src/corelib/io/qprocess_unix.cpp

@@ -1111,10 +1111,6 @@ bool QProcessPrivate::waitForDeadChild()
     return true;
 }
 
-void QProcessPrivate::_q_notified()
-{
-}
-
 #if defined(QPROCESS_USE_SPAWN)
 bool QProcessPrivate::startDetached(const QString &program, const QStringList &arguments, const QString &workingDirectory, qint64 *pid)
 {

src/corelib/io/qprocess_win.cpp

@@ -41,7 +41,6 @@
 #include <qelapsedtimer.h>
 #include <qfileinfo.h>
 #include <qregexp.h>
-#include <qtimer.h>
 #include <qwineventnotifier.h>
 #include <private/qthread_p.h>
 #include <qdebug.h>
@@ -58,8 +57,6 @@ QT_BEGIN_NAMESPACE
 
 //#define QPROCESS_DEBUG
 
-#define NOTIFYTIMEOUT 100
-
 static void qt_create_pipe(Q_PIPE *pipe, bool isInputPipe)
 {
     // Anomymous pipes do not support asynchronous I/O. Thus we
@@ -543,9 +540,6 @@ void QProcessPrivate::startProcess()
         processFinishedNotifier = new QWinEventNotifier(pid->hProcess, q);
         QObject::connect(processFinishedNotifier, SIGNAL(activated(HANDLE)), q, SLOT(_q_processDied()));
         processFinishedNotifier->setEnabled(true);
-        notifier = new QTimer(q);
-        QObject::connect(notifier, SIGNAL(timeout()), q, SLOT(_q_notified()));
-        notifier->start(NOTIFYTIMEOUT);
     }
 
     _q_startupNotification();
@@ -810,6 +804,8 @@ qint64 QProcessPrivate::writeToStdin(const char *data, qint64 maxlen)
 
     if (!stdinChannel.writer) {
         stdinChannel.writer = new QWindowsPipeWriter(stdinChannel.pipe[1], q);
+        QObjectPrivate::connect(stdinChannel.writer, &QWindowsPipeWriter::canWrite,
+                                this, &QProcessPrivate::_q_canWrite);
         stdinChannel.writer->start();
     }
 
@@ -828,17 +824,6 @@ bool QProcessPrivate::waitForWrite(int msecs)
     return false;
 }
 
-void QProcessPrivate::_q_notified()
-{
-    notifier->stop();
-
-    if (!stdinChannel.buffer.isEmpty() && (!stdinChannel.writer || stdinChannel.writer->waitForWrite(0)))
-        _q_canWrite();
-
-    if (processState != QProcess::NotRunning)
-        notifier->start(NOTIFYTIMEOUT);
-}
-
 bool QProcessPrivate::startDetached(const QString &program, const QStringList &arguments, const QString &workingDir, qint64 *pid)
 {
     QString args = qt_create_commandline(program, arguments);

src/corelib/io/qprocess_wince.cpp

@@ -288,10 +288,6 @@ bool QProcessPrivate::waitForWrite(int msecs)
     return false;
 }
 
-void QProcessPrivate::_q_notified()
-{
-}
-
 bool QProcessPrivate::startDetached(const QString &program, const QStringList &arguments, const QString &workingDir, qint64 *pid)
 {
     Q_UNUSED(workingDir);