38be0d1383
This is the beginning of revision history for this module. If you want to look at revision history older than this, please refer to the Qt Git wiki for how to use Git history grafting. At the time of writing, this wiki is located here: http://qt.gitorious.org/qt/pages/GitIntroductionWithQt If you have already performed the grafting and you don't see any history beyond this commit, try running "git log" with the "--follow" argument. Branched from the monolithic repo, Qt master branch, at commit 896db169ea224deb96c59ce8af800d019de63f12
115 lines
3.0 KiB
C++
115 lines
3.0 KiB
C++
/****************************************************************************
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**
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** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
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** All rights reserved.
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** Contact: Nokia Corporation (qt-info@nokia.com)
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**
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** This file is part of the test suite of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:LGPL$
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** No Commercial Usage
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** This file contains pre-release code and may not be distributed.
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** You may use this file in accordance with the terms and conditions
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** contained in the Technology Preview License Agreement accompanying
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** this package.
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**
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** GNU Lesser General Public License Usage
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** General Public License version 2.1 as published by the Free Software
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** Foundation and appearing in the file LICENSE.LGPL included in the
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** packaging of this file. Please review the following information to
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** ensure the GNU Lesser General Public License version 2.1 requirements
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** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
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**
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** In addition, as a special exception, Nokia gives you certain additional
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** rights. These rights are described in the Nokia Qt LGPL Exception
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** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
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**
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** If you have questions regarding the use of this file, please contact
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** Nokia at qt-info@nokia.com.
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**
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**
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**
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**
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**
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**
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**
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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#ifndef QTHREADONCE_H
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#define QTHREADONCE_H
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#include <QtCore/qglobal.h>
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#include <QtCore/qatomic.h>
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QT_BEGIN_HEADER
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QT_MODULE(Core)
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#ifndef QT_NO_THREAD
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class QOnceControl
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{
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public:
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QOnceControl(QBasicAtomicInt *);
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~QOnceControl();
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bool mustRunCode();
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void done();
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private:
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QBasicAtomicInt *gv;
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union {
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qint32 extra;
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void *d;
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};
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};
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#define Q_ONCE_GV_NAME2(prefix, line) prefix ## line
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#define Q_ONCE_GV_NAME(prefix, line) Q_ONCE_GV_NAME2(prefix, line)
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#define Q_ONCE_GV Q_ONCE_GV_NAME(_q_once_, __LINE__)
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#define Q_ONCE \
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static QBasicAtomicInt Q_ONCE_GV = Q_BASIC_ATOMIC_INITIALIZER(0); \
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if (0){} else \
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for (QOnceControl _control_(&Q_ONCE_GV); _control_.mustRunCode(); _control_.done())
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template<typename T>
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class QSingleton
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{
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// this is a POD-like class
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struct Destructor
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{
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T *&pointer;
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Destructor(T *&ptr) : pointer(ptr) {}
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~Destructor() { delete pointer; }
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};
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public:
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T *_q_value;
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QBasicAtomicInt _q_guard;
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inline T *value()
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{
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for (QOnceControl control(&_q_guard); control.mustRunCode(); control.done()) {
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_q_value = new T();
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static Destructor cleanup(_q_value);
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}
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return _q_value;
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}
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inline T& operator*() { return *value(); }
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inline T* operator->() { return value(); }
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inline operator T*() { return value(); }
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};
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#endif // QT_NO_THREAD
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QT_END_HEADER
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#endif
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