/********************************************************************
**                Image Component Library (ICL)                    **
**                                                                 **
** Copyright (C) 2006-2013 CITEC, University of Bielefeld          **
**                         Neuroinformatics Group                  **
** Website: www.iclcv.org and                                      **
**          http://opensource.cit-ec.de/projects/icl               **
**                                                                 **
** File   : ICLUtils/src/ICLUtils/UncopiedInstance.h               **
** Module : ICLUtils                                               **
** Authors: Christof Elbrechter                                    **
**                                                                 **
**                                                                 **
** GNU LESSER GENERAL PUBLIC LICENSE                               **
** This file may be used under the terms of the GNU Lesser General **
** Public License version 3.0 as published by the                  **
**                                                                 **
** Free Software Foundation and appearing in the file LICENSE.LGPL **
** included in the packaging of this file.  Please review the      **
** following information to ensure the license requirements will   **
** be met: http://www.gnu.org/licenses/lgpl-3.0.txt                **
**                                                                 **
** The development of this software was supported by the           **
** Excellence Cluster EXC 277 Cognitive Interaction Technology.    **
** The Excellence Cluster EXC 277 is a grant of the Deutsche       **
** Forschungsgemeinschaft (DFG) in the context of the German       **
** Excellence Initiative.                                          **
**                                                                 **
********************************************************************/

#pragma once

#include <ICLUtils/CompatMacros.h>

namespace icl{
  namespace utils{
    
    /// Utility class for class instances that are created brand new on copy
    /** Consider the following problem:
        You have a class with some mutex'ed interface
        \code
        class Camera{
           float *data;
           Mutex mutex;
           public:
           void lock(){ mutex.lock(); }
           void unlock() { mutex.unlock(); }
           ...
        };
        \endcode
        As the mutex class is an instance of the Uncopyable interfaces, it cannot 
        be copied. Furthermore, all classes X that have a member of type Mutex are Uncopyable too, unless,
        A special copy constructor and assignment operator for X is defined. This can be bypassed using the
        UncopiedInstance interface.\n
        Due to template based inheritance, Uncopied instances can be used as their (templated) child instances.
        One major drawback is, that the wrapped T instance (wrapped by inheritance) is always constructed using
        the ()-empty constructor.\n
        The Camera class from above can simply use the default copy constructor and assignment operator if we
        use an UncopiedInstance<Mutex> instead of the Mutex class itself.
        \code
        class Camera{
           float *data;
           UncopiedInstance<Mutex> mutex;
           public:
           void lock(){ mutex.lock(); }
           void unlock() { mutex.unlock(); }
           ...
        };
        \endcode
    */
    template<class T>
    class UncopiedInstance : public T{
      public:
      
      /// copy from parent constructor
      inline UncopiedInstance(const T &t):T(t){}
      
      /// default constructor calls T()
      inline UncopiedInstance():T(){}
      
      /// default copy constructor calls T()
      inline UncopiedInstance(const UncopiedInstance &other):T(){}
      
      /// assignment operator (does NOT call T::operator=(other))
      inline UncopiedInstance &operator=(const UncopiedInstance &other){
        return *this;
      }
    };
  } // namespace utils
}