source: trunk/src/sql/qsqldriverplugin.cpp

/****************************************************************************
** $Id: qsqldriverplugin.cpp 2051 2007-02-21 10:04:20Z chehrlic $
**
** Implementation of QSqlDriverPlugin class
**
** Created : 2001-09-20
**
** Copyright (C) 2001-2007 Trolltech ASA.  All rights reserved.
**
** This file is part of the sql module of the Qt GUI Toolkit.
**
** This file may be distributed under the terms of the Q Public License
** as defined by Trolltech ASA 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.
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**********************************************************************/

#include "qsqldriverplugin.h"

#ifndef QT_NO_SQL
#ifndef QT_NO_COMPONENT

#include "qsqldriverinterface_p.h"

/*!
    \class QSqlDriverPlugin qsqldriverplugin.h
    \brief The QSqlDriverPlugin class provides an abstract base for custom QSqlDriver plugins.

    \ingroup plugins
    \mainclass

    The SQL driver plugin is a simple plugin interface that makes it
    easy to create your own SQL driver plugins that can be loaded
    dynamically by Qt.

    Writing a SQL plugin is achieved by subclassing this base class,
    reimplementing the pure virtual functions keys() and create(), and
    exporting the class with the \c Q_EXPORT_PLUGIN macro. See the SQL
    plugins that come with Qt for example implementations (in the
    \c{plugins/src/sqldrivers} subdirectory of the source
    distribution). Read the \link plugins-howto.html plugins
    documentation\endlink for more information on plugins.
*/

/*!
    \fn QStringList QSqlDriverPlugin::keys() const

    Returns the list of drivers (keys) this plugin supports.

    These keys are usually the class names of the custom drivers that
    are implemented in the plugin.

    \sa create()
*/

/*!
    \fn QSqlDriver* QSqlDriverPlugin::create( const QString& key )

    Creates and returns a QSqlDriver object for the driver key \a key.
    The driver key is usually the class name of the required driver.

    \sa keys()
*/

class QSqlDriverPluginPrivate : public QSqlDriverFactoryInterface
{
public:
    QSqlDriverPluginPrivate( QSqlDriverPlugin *p )
        : plugin( p )
    {
    }
    virtual ~QSqlDriverPluginPrivate();

    QRESULT queryInterface( const QUuid &iid, QUnknownInterface **iface );
    Q_REFCOUNT;

    QStringList featureList() const;
    QSqlDriver *create( const QString &key );

private:
    QSqlDriverPlugin *plugin;
};

QSqlDriverPluginPrivate::~QSqlDriverPluginPrivate()
{
    delete plugin;
}

QRESULT QSqlDriverPluginPrivate::queryInterface( const QUuid &iid, QUnknownInterface **iface )
{
    *iface = 0;

    if ( iid == IID_QUnknown )
        *iface = this;
    else if ( iid == IID_QFeatureList )
        *iface = this;
    else if ( iid == IID_QSqlDriverFactory )
        *iface = this;
    else
        return QE_NOINTERFACE;

    (*iface)->addRef();
    return QS_OK;
}

QStringList QSqlDriverPluginPrivate::featureList() const
{
    return plugin->keys();
}

QSqlDriver *QSqlDriverPluginPrivate::create( const QString &key )
{
    return plugin->create( key );
}

/*!
    Constructs a SQL driver plugin. This is invoked automatically by
    the \c Q_EXPORT_PLUGIN macro.
*/

QSqlDriverPlugin::QSqlDriverPlugin()
    : QGPlugin( d = new QSqlDriverPluginPrivate( this ) )
{
}

/*!
    Destroys the SQL driver plugin.

    You never have to call this explicitly. Qt destroys a plugin
    automatically when it is no longer used.
*/
QSqlDriverPlugin::~QSqlDriverPlugin()
{
    // don't delete d, as this is deleted by d
}

#endif // QT_NO_COMPONENT
#endif // QT_NO_SQL