MutexGuard.h

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/*********************************************************\
 *  File: MutexGuard.h                                   *
 *
 *  Copyright (C) 2002-2012 The PixelLight Team (http://www.pixellight.org/)
 *
 *  This file is part of PixelLight.
 *
 *  PixelLight is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  PixelLight is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with PixelLight. If not, see <http://www.gnu.org/licenses/>.
\*********************************************************/


#ifndef __PLCORE_MUTEXGUARD_H__
#define __PLCORE_MUTEXGUARD_H__
#pragma once


//[-------------------------------------------------------]
//[ Includes                                              ]
//[-------------------------------------------------------]
#include "PLCore/PLCore.h"


//[-------------------------------------------------------]
//[ Namespace                                             ]
//[-------------------------------------------------------]
namespace PLCore {


//[-------------------------------------------------------]
//[ Forward declarations                                  ]
//[-------------------------------------------------------]
class Mutex;


//[-------------------------------------------------------]
//[ Classes                                               ]
//[-------------------------------------------------------]
/**
*  @brief
*    Mutex guard class ("Scoped Locking"-idiom, also known as "synchronized block")
*
*  @remarks
*    When using a mutex in more complex situations there's the risk that one forgets the unlock a locked mutex. To avoid this
*    situation it's a good idea to use this mutex guard on the runtime stack (the runtime stack is your friend!) in order to
*    lock the mutex and automatically unlock it as soon as the critical scope is left.
*/
class MutexGuard {


    //[-------------------------------------------------------]
    //[ Public functions                                      ]
    //[-------------------------------------------------------]
    public:
        /**
        *  @brief
        *    Constructor
        *
        *  @param[in] cMutex
        *    Mutex to use, just referenced, must stay valid as long as this mutex guard exists!
        *
        *  @note
        *    - Blocking if the mutex is already locked
        *    - Use the constructor with a timeout to avoid potential deadlocks
        */
        inline MutexGuard(Mutex &cMutex);

        /**
        *  @brief
        *    Constructor
        *
        *  @param[in] cMutex
        *    Mutex to use, just referenced, must stay valid as long as this mutex guard exists!
        *  @param[in] nTimeout
        *    Timeout in milliseconds
        *
        *  @note
        *    - 'nTimeout = 0' means: Return immediately if the mutex is already locked
        */
        inline MutexGuard(Mutex &cMutex, uint64 nTimeout);

        /**
        *  @brief
        *    Destructor
        */
        inline ~MutexGuard();

        /**
        *  @brief
        *    Returns whether the used mutex was locked successfully
        *
        *  @return
        *    'true' if the used mutex was locked successfully, else 'false'
        */
        inline bool IsLocked() const;

        /**
        *  @brief
        *    Returns the used mutex
        *
        *  @return
        *    The used mutex
        */
        inline Mutex &GetMutex() const;


    //[-------------------------------------------------------]
    //[ Private functions                                     ]
    //[-------------------------------------------------------]
    private:
        /**
        *  @brief
        *    Copy constructor
        *
        *  @param[in] cSource
        *    Source to copy from
        */
        inline MutexGuard(const MutexGuard &cSource);

        /**
        *  @brief
        *    Copy operator
        *
        *  @param[in] cSource
        *    Source to copy from
        *
        *  @return
        *    Reference to this instance
        */
        inline MutexGuard &operator =(const MutexGuard &cSource);


    //[-------------------------------------------------------]
    //[ Private data                                          ]
    //[-------------------------------------------------------]
    private:
        Mutex *m_pMutex;    /**< Pointer to the used mutex, always valid! */
        bool   m_bLocked;   /**< 'true' if the used mutex was locked successfully, else 'false' */


};


//[-------------------------------------------------------]
//[ Namespace                                             ]
//[-------------------------------------------------------]
} // PLCore


//[-------------------------------------------------------]
//[ Implementation                                        ]
//[-------------------------------------------------------]
#include "PLCore/System/MutexGuard.inl"


#endif // __PLCORE_MUTEXGUARD_H__