Qt Toolkit - qguardedptr.h include file

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# qguardedptr.h

This is the verbatim text of the qguardedptr.h include file. It is provided only for illustration; the copyright remains with Trolltech.

    /****************************************************************************
    ** $Id: qt/src/kernel/qguardedptr.h   2.2.0   edited 2000-08-25 $
    **
    ** Definition of QGuardedPtr class
    **
    ** Created : 990929
    **
    ** Copyright (C) 1992-2000 Trolltech AS.  All rights reserved.
    **
    ** This file is part of the kernel module of the Qt GUI Toolkit.
    **
    ** This file may be distributed under the terms of the Q Public License
    ** as defined by Trolltech AS of Norway and appearing in the file
    ** LICENSE.QPL included in the packaging of this file.
    **
    ** This file may be distributed and/or modified under the terms of the
    ** GNU General Public License version 2 as published by the Free Software
    ** Foundation and appearing in the file LICENSE.GPL included in the
    ** packaging of this file.
    **
    ** Licensees holding valid Qt Enterprise Edition or Qt Professional Edition
    ** licenses may use this file in accordance with the Qt Commercial License
    ** Agreement provided with the Software.
    **
    ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
    ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
    **
    ** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for
    **   information about Qt Commercial License Agreements.
    ** See http://www.trolltech.com/qpl/ for QPL licensing information.
    ** See http://www.trolltech.com/gpl/ for GPL licensing information.
    **
    ** Contact info@trolltech.com if any conditions of this licensing are
    ** not clear to you.
    **
    **********************************************************************/

    #ifndef QGUARDEDPTR_H
    #define QGUARDEDPTR_H

    #ifndef QT_H
    #include "qobject.h"
    #endif // QT_H

    class Q_EXPORT QGuardedPtrPrivate : public  QObject, public QShared
    {
        Q_OBJECT
    public:
        QGuardedPtrPrivate( QObject*);
        ~QGuardedPtrPrivate();

        QObject* object() const;
    private slots:
        void objectDestroyed();
    private:
        QObject* obj;
    };

    template <class T> class Q_EXPORT QGuardedPtr
    {
    public:
        QGuardedPtr()
        {
            priv = new QGuardedPtrPrivate( 0 );
        }
        QGuardedPtr( T* o)
        {
    #if defined(Q_TEMPLATE_NEEDS_EXPLICIT_CONVERSION)
            priv = new QGuardedPtrPrivate( (QObject*)o );
    #else
            priv = new QGuardedPtrPrivate( o );
    #endif
        }
        QGuardedPtr(const QGuardedPtr<T> &p)
        {
            priv = p.priv;
            ref();
        }
        ~QGuardedPtr()
        {
            deref();
        }

        QGuardedPtr<T> &operator=(const QGuardedPtr<T> &p)
        {
            if ( priv != p.priv ) {
                deref();
                priv = p.priv;
                ref();
            }
            return *this;
        }

        QGuardedPtr<T> &operator=(T* o)
        {
            deref();
    #if defined(Q_TEMPLATE_NEEDS_EXPLICIT_CONVERSION)
            priv = new QGuardedPtrPrivate( (QObject*)o );
    #else
            priv = new QGuardedPtrPrivate( o );
    #endif
            return *this;
        }

        bool operator==( const QGuardedPtr<T> &p ) const
        {
            return priv->object() == p.priv->object();
        }

        bool operator!= ( const QGuardedPtr<T>& p ) const
        {
            return !( *this == p );
        }

        bool isNull() const
        {
            return !priv->object();
        }

        T* operator->() const
        {
            return (T*) priv->object();
        }

        T& operator*() const
        {
            return *( (T*)priv->object() );
        }

        operator T*() const
        {
            return (T*) priv->object();
        }

    private:
        void ref()
        {
            priv->ref();
        }
        void deref()
        {
            if ( priv->deref() )
                delete priv;
        }
        QGuardedPtrPrivate* priv;
    };

    inline QObject* QGuardedPtrPrivate::object() const
    {
        return obj;
    }

    #endif