/****************************************************************************
**
** https://www.qxorm.com/
** Copyright (C) 2013 Lionel Marty (contact@qxorm.com)
**
** This file is part of the QxOrm library
**
** This software is provided 'as-is', without any express or implied
** warranty. In no event will the authors be held liable for any
** damages arising from the use of this software
**
** Commercial Usage
** Licensees holding valid commercial QxOrm licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Lionel Marty
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file 'license.gpl3.txt' included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met : http://www.gnu.org/copyleft/gpl.html
**
** If you are unsure which license is appropriate for your use, or
** if you have questions regarding the use of this file, please contact :
** contact@qxorm.com
**
****************************************************************************/

#ifndef _QX_SINGLETON_H_
#define _QX_SINGLETON_H_

#ifdef _MSC_VER
#pragma once
#endif

/*!
 * \file QxSingleton.h
 * \author Lionel Marty
 * \ingroup QxSingleton
 * \brief Concrete class to define a thread-safe singleton of QxOrm library
 */

#include <QtCore/qmutex.h>
#include <QtCore/qcoreapplication.h>

#include <QxSingleton/IxSingleton.h>

namespace qx {

/*!
 * \ingroup QxSingleton
 * \brief qx::QxSingleton<T> : concrete class to define a thread-safe singleton of type T
 */
template <class T>
class QxSingleton : public IxSingleton
{

private:

   static T *     m_pSingleton;        //!< Singleton -> only 1 instance allowed
   static QMutex  m_oMutexSingleton;   //!< Mutex -> 'QxSingleton' is thread-safe

protected:

   QxSingleton(const QString & sKey) : IxSingleton(sKey) { ; }
   virtual ~QxSingleton() { ; }

public:

   static T * getSingleton();
   static void deleteSingleton();

protected:

   static bool isSingletonNull() { return (m_pSingleton == NULL); }

   virtual void deleteInstance() { QxSingleton<T>::deleteSingleton(); }

};

} // namespace qx

#include "../../inl/QxSingleton/QxSingleton.inl"

#endif // _QX_SINGLETON_H_