tests/auto/qthreadonce/qthreadonce.h
changeset 0 1918ee327afb
child 4 3b1da2848fc7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/auto/qthreadonce/qthreadonce.h	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,114 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+
+#ifndef QTHREADONCE_H
+#define QTHREADONCE_H
+
+#include <QtCore/qglobal.h>
+#include <QtCore/qatomic.h>
+
+QT_BEGIN_HEADER
+
+QT_MODULE(Core)
+
+#ifndef QT_NO_THREAD
+
+class QOnceControl
+{
+public:
+    QOnceControl(QBasicAtomicInt *);
+    ~QOnceControl();
+
+    bool mustRunCode();
+    void done();
+
+private:
+    QBasicAtomicInt *gv;
+    union {
+        qint32 extra;
+        void *d;
+    };
+};
+
+#define Q_ONCE_GV_NAME2(prefix, line)   prefix ## line
+#define Q_ONCE_GV_NAME(prefix, line)    Q_ONCE_GV_NAME2(prefix, line)
+#define Q_ONCE_GV                       Q_ONCE_GV_NAME(_q_once_, __LINE__)
+
+#define Q_ONCE \
+    static QBasicAtomicInt Q_ONCE_GV = Q_BASIC_ATOMIC_INITIALIZER(0);   \
+    if (0){} else                                                       \
+        for (QOnceControl _control_(&Q_ONCE_GV); _control_.mustRunCode(); _control_.done())
+
+template<typename T>
+class QSingleton
+{
+    // this is a POD-like class
+    struct Destructor
+    {
+        T *&pointer;
+        Destructor(T *&ptr) : pointer(ptr) {}
+        ~Destructor() { delete pointer; }
+    };
+
+public:
+    T *_q_value;
+    QBasicAtomicInt _q_guard;
+
+    inline T *value()
+    {
+        for (QOnceControl control(&_q_guard); control.mustRunCode(); control.done()) {
+            _q_value = new T();
+            static Destructor cleanup(_q_value);
+        }
+        return _q_value;
+    }
+
+    inline T& operator*() { return *value(); }
+    inline T* operator->() { return value(); }
+    inline operator T*() { return value(); }
+};
+
+#endif // QT_NO_THREAD
+
+QT_END_HEADER
+
+#endif