Support more than 62 instances of QWinEventNotifier

QWinEventNotifiers were limited to 62 instances, because of
WaitForMultipleObject's limitation to MAXIMUM_WAIT_OBJECTS - 1 handles.

Use the RegisterWaitForSingleObject API which does not have this
restriction and executes waits in threads managed by the system. A
central manual reset event per event dispatcher is signaled in the
RegisterWaitForSingleObject callback and waited for in the event loop.

[ChangeLog][QtCore][QWinEventNotifier] QWinEventNotifier is not
restricted to 62 instances anymore.

Task-number: QTBUG-8819
Change-Id: I2c749951453a4b699cc50dada0d6017440b67a4a
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

1 files changed, 81 insertions, 0 deletions

diff --git a/src/corelib/kernel/qwineventnotifier_p.h b/src/corelib/kernel/qwineventnotifier_p.h
new file mode 100644
index 0000000000..bddeaaf134
--- /dev/null
+++ b/src/corelib/kernel/qwineventnotifier_p.h
@@ -0,0 +1,81 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QWINEVENTNOTIFIER_P_H
+#define QWINEVENTNOTIFIER_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include "qwineventnotifier.h"
+
+#include <private/qobject_p.h>
+#include <QtCore/qt_windows.h>
+
+QT_BEGIN_NAMESPACE
+
+class QWinEventNotifierPrivate : public QObjectPrivate
+{
+    Q_DECLARE_PUBLIC(QWinEventNotifier)
+public:
+    QWinEventNotifierPrivate()
+    : handleToEvent(0), enabled(false) {}
+    QWinEventNotifierPrivate(HANDLE h, bool e)
+    : handleToEvent(h), enabled(e) {}
+
+    static QWinEventNotifierPrivate *get(QWinEventNotifier *q) { return q->d_func(); }
+    bool registerWaitObject();
+    void unregisterWaitObject();
+
+    HANDLE handleToEvent;
+    HANDLE waitHandle = NULL;
+    bool enabled;
+};
+
+QT_END_NAMESPACE
+
+#endif // QWINEVENTNOTIFIER_P_H