Teuchos_ConstNonconstObjectContainer.hpp

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// @HEADER
// *****************************************************************************
//                    Teuchos: Common Tools Package
//
// Copyright 2004 NTESS and the Teuchos contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER

#ifndef TEUCHOS_CONST_NONCONST_OBJECT_CONTAINER_HPP
#define TEUCHOS_CONST_NONCONST_OBJECT_CONTAINER_HPP

#include "Teuchos_RCP.hpp"


namespace Teuchos {


template<class ObjType>
class ConstNonconstObjectContainer {
public:
  ConstNonconstObjectContainer()
    :constObj_(null),isConst_(true) {}
  ConstNonconstObjectContainer( const RCP<ObjType> &obj )
    { initialize(obj); }
  ConstNonconstObjectContainer( const RCP<const ObjType> &obj )
    { initialize(obj); }
  void initialize( const RCP<ObjType> &obj )
    {
      TEUCHOS_TEST_FOR_EXCEPTION(is_null(obj), NullReferenceError, "Error!");
      constObj_ = obj;
      isConst_ = false;
    }
  void initialize( const RCP<const ObjType> &obj )
    {
      TEUCHOS_TEST_FOR_EXCEPTION(is_null(obj), NullReferenceError, "Error!");
      constObj_ = obj;
      isConst_ = true;
    }
  void uninitialize()
    { constObj_=null; isConst_=true; }
  ConstNonconstObjectContainer<ObjType>& operator=(ENull)
    { uninitialize(); return *this; }
  bool isConst() const
    { return isConst_; }
  RCP<ObjType> getNonconstObj() const
    {
      TEUCHOS_TEST_FOR_EXCEPTION(
        constObj_.get() && isConst_, NonconstAccessError,
        "Error, the object of reference type \""<<TypeNameTraits<ObjType>::name()
        <<"\" was given as a const-only object and non-const access is not allowed."
        );
      return rcp_const_cast<ObjType>(constObj_);
    }
  RCP<const ObjType> getConstObj() const
    { return constObj_; }
  RCP<const ObjType> operator()() const
    { return getConstObj(); }
  const ObjType* operator->() const
    { return &*getConstObj(); } // Does assert also!
  const ObjType& operator*() const
    { return *getConstObj(); }
  operator RCP<const ObjType>() const
    { return getConstObj(); }
  int count() const
    { return constObj_.count(); }

private:
  RCP<const ObjType> constObj_;
  bool isConst_;
};


template<class T>
bool is_null( const ConstNonconstObjectContainer<T> &p )
{ return is_null(p.getConstObj()); }


template<class T>
bool nonnull( const ConstNonconstObjectContainer<T> &p )
{ return nonnull(p.getConstObj()); }


} // namespace Teuchos


#endif // TEUCHOS_CONST_NONCONST_OBJECT_CONTAINER_HPP