src/xmlpatterns/api/qreferencecountedvalue_p.h
author Eckhart Koeppen <eckhart.koppen@nokia.com>
Thu, 08 Apr 2010 14:19:33 +0300
branchRCL_3
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qt:70947f0f93d948bc89b3b43d00da758a51f1ef84
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/****************************************************************************
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**
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** Copyright (C) 2010 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 QtXmlPatterns module 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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//
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//  W A R N I N G
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//  -------------
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//
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// This file is not part of the Qt API.  It exists purely as an
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// implementation detail.  This header file may change from version to
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// version without notice, or even be removed.
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//
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// We mean it.
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#ifndef QPatternist_ReferenceCountedValue_p_h
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#define QPatternist_ReferenceCountedValue_p_h
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QT_BEGIN_HEADER
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QT_BEGIN_NAMESPACE
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namespace QPatternist
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{
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/*!
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   \class ReferenceCountedValue
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   \internal
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   \since 4.4
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   \brief A template class that reference counts a value.
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   This class is useful when an instance needs to have ownership semantics
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   as if it was value based. A typical examples is a QObject pointer, which
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   doesn't have a single owner.
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   This is achieved through storing a copy of the object as
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   a member inside ReferenceCountedValue, which never is copied. It will
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   stay in scope until the last reference to the ReferenceCountedValue instance
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   is removed, and subsequently ReferenceCountedValue is deleted and hence also
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   the contained value. One should use ReferenceCountedValue by passing around
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   copies of Ptr, which is a typedef for the QExplicitlySharedDataPointer
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   smart pointer.
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*/
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    template<typename T>
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    class ReferenceCountedValue : public QSharedData
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    {
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    public:
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        typedef QExplicitlySharedDataPointer<ReferenceCountedValue<T> > Ptr;
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        inline ReferenceCountedValue(T *const v) : value(v)
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        {
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        }
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        inline ~ReferenceCountedValue()
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        {
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            delete value;
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        }
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        T *const value;
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    private:
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        /*!
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          Disabled, no implementation provided.
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         */
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        inline ReferenceCountedValue();
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        Q_DISABLE_COPY(ReferenceCountedValue)
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    };
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}
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QT_END_NAMESPACE
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QT_END_HEADER
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#endif