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/****************************************************************************
**
** Implementation of QObjectCleanupHandler class
**
** Copyright (C) 2000-2008 Trolltech ASA. All rights reserved.
**
** This file is part of the kernel module of the Qt GUI Toolkit.
**
** This file may be used under the terms of the GNU General
** Public License versions 2.0 or 3.0 as published by the Free
** Software Foundation and appearing in the files LICENSE.GPL2
** and LICENSE.GPL3 included in the packaging of this file.
** Alternatively you may (at your option) use any later version
** of the GNU General Public License if such license has been
** publicly approved by Trolltech ASA (or its successors, if any)
** and the KDE Free Qt Foundation.
**
** Please review the following information to ensure GNU General
** Public Licensing requirements will be met:
** http://trolltech.com/products/qt/licenses/licensing/opensource/.
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://trolltech.com/products/qt/licenses/licensing/licensingoverview
** or contact the sales department at sales@trolltech.com.
**
** This file may be used under the terms of the Q Public License as
** defined by Trolltech ASA and appearing in the file LICENSE.QPL
** included in the packaging of this file. Licensees holding valid Qt
** Commercial 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 WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE. Trolltech reserves all rights not granted
** herein.
**
**********************************************************************/
#include "qobjectcleanuphandler.h"
#include "qobjectlist.h"
/*!
\class QObjectCleanupHandler qobjectcleanuphandler.h
\brief The QObjectCleanupHandler class watches the lifetime of multiple QObjects.
\ingroup objectmodel
A QObjectCleanupHandler is useful whenever you need to know when a
number of \l{QObject}s that are owned by someone else have been
deleted. This is important, for example, when referencing memory
in an application that has been allocated in a shared library.
Example:
\code
class FactoryComponent : public FactoryInterface, public QLibraryInterface
{
public:
...
QObject *createObject();
bool init();
void cleanup();
bool canUnload() const;
private:
QObjectCleanupHandler objects;
};
// allocate a new object, and add it to the cleanup handler
QObject *FactoryComponent::createObject()
{
return objects.add( new QObject() );
}
// QLibraryInterface implementation
bool FactoryComponent::init()
{
return TRUE;
}
void FactoryComponent::cleanup()
{
}
// it is only safe to unload the library when all QObject's have been destroyed
bool FactoryComponent::canUnload() const
{
return objects.isEmpty();
}
\endcode
*/
/*!
Constructs an empty QObjectCleanupHandler.
*/
QObjectCleanupHandler::QObjectCleanupHandler()
: QObject(), cleanupObjects( 0 )
{
}
/*!
Destroys the cleanup handler. All objects in this cleanup handler
will be deleted.
*/
QObjectCleanupHandler::~QObjectCleanupHandler()
{
clear();
}
/*!
Adds \a object to this cleanup handler and returns the pointer to
the object.
*/
QObject* QObjectCleanupHandler::add( QObject* object )
{
if ( !object )
return 0;
if ( !cleanupObjects ) {
cleanupObjects = new QObjectList;
cleanupObjects->setAutoDelete( TRUE );
}
connect( object, SIGNAL(destroyed(QObject*)), this, SLOT(objectDestroyed(QObject*)) );
cleanupObjects->insert( 0, object );
return object;
}
/*!
Removes the \a object from this cleanup handler. The object will
not be destroyed.
*/
void QObjectCleanupHandler::remove( QObject *object )
{
if ( !cleanupObjects )
return;
if ( cleanupObjects->findRef( object ) >= 0 ) {
(void) cleanupObjects->take();
disconnect( object, SIGNAL(destroyed(QObject*)), this, SLOT(objectDestroyed(QObject*)) );
}
}
/*!
Returns TRUE if this cleanup handler is empty or if all objects in
this cleanup handler have been destroyed; otherwise return FALSE.
*/
bool QObjectCleanupHandler::isEmpty() const
{
return cleanupObjects ? cleanupObjects->isEmpty() : TRUE;
}
/*!
Deletes all objects in this cleanup handler. The cleanup handler
becomes empty.
*/
void QObjectCleanupHandler::clear()
{
delete cleanupObjects;
cleanupObjects = 0;
}
void QObjectCleanupHandler::objectDestroyed( QObject*object )
{
if ( cleanupObjects )
cleanupObjects->setAutoDelete( FALSE );
remove( object );
if ( cleanupObjects )
cleanupObjects->setAutoDelete( TRUE );
}
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