/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Copyright (C) 2011-2026 OpenFOAM Foundation
     \\/     M anipulation  |
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.

    OpenFOAM is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    OpenFOAM 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 General Public License
    for more details.

    You should have received a copy of the GNU General Public License
    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.

Class
    Foam::tmp

Description
    A class for managing temporary objects

SourceFiles
    tmpI.H

See also
    Foam::refCount
    Foam::autoPtr

\*---------------------------------------------------------------------------*/

#ifndef tmp_H
#define tmp_H

#include "refCount.H"
#include "word.H"
#include "expressionExpressionable.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

namespace Foam
{

/*---------------------------------------------------------------------------*\
                             Class tmp Declaration
\*---------------------------------------------------------------------------*/

template<class T>
class tmp
{
    // Private Data

        //- Object types
        enum type
        {
            REUSABLE_TMP,
            NON_RESUSABLE_TMP,
            CONST_REF
        };

        //- Type of object
        type type_;

        //- Pointer to object
        mutable T* ptr_;


    // Private Member Functions

        //- Return true if the object is a reusable or non-reusable temporary
        inline bool isAnyTmp() const;


    // Private Member Operators

        //- Increment the reference count
        inline void operator++();


public:

    // Public Type Definitions

        //- The type
        typedef T Type;

        //- The reference counting class
        typedef Foam::refCount refCount;


    // Constructors

        //- Store object pointer of a non-reusable or reusable temporary object
        inline explicit tmp(T* = 0, bool nonReusable = false);

        //- Store object const reference
        inline tmp(const T&);

        //- Construct copy and increment reference count
        inline tmp(const tmp<T>&);

        //- Construct copy moving content, does not increment reference count
        inline tmp(tmp<T>&&);

        //- Construct copy moving content, does not increment reference count
        inline tmp(const tmp<T>&&);

        //- Construct copy transferring content of temporary if required
        inline tmp(const tmp<T>&, bool allowTransfer);

        //- Construct from an expression
        template<class Expression, class = EnableIfExpression<Expression>>
        inline tmp(const Expression& e);


    //- Destructor. Deletes temporary object when the reference count is 0.
    inline ~tmp();


    // Member Functions

        // Access

            //- Return true if this is really a temporary object
            inline bool isTmp() const;

            //- Return true if this temporary object empty,
            //  ie, a temporary without allocation
            inline bool empty() const;

            //- Is this temporary object valid,
            //  ie, it is a reference or a temporary that has been allocated
            inline bool valid() const;

            //- Return the type name of the tmp
            //  constructed from the type name of T
            inline word typeName() const;


        // Edit

            //- Return non-const reference or generate a fatal error
            //  if the object is const.
            inline T& ref() const;

            //- Return tmp pointer for reuse.
            //  Returns a clone if the object is not a temporary
            inline T* ptr() const;

            //- If object pointer points to valid object:
            //  delete object and set pointer to nullptr
            inline void clear() const;


    // Member Operators

        #ifdef NON_CONST_TMP
        //- Deprecated non-const dereference operator.
        //  Use ref() where non-const access is required
        inline T& operator()();
        #endif

        //- Const dereference operator
        inline const T& operator()() const;

        //- Const cast to the underlying type reference
        inline operator const T&() const;

        //- Return object pointer
        inline T* operator->();

        //- Return const object pointer
        inline const T* operator->() const;

        //- Assignment to pointer changing this tmp to a temporary T
        inline void operator=(T*);

        //- Assignment transferring the temporary T to this tmp
        inline void operator=(const tmp<T>&);

        //- Move assignment transferring the temporary T to this tmp
        inline void operator=(tmp<T>&&);

        //- Move assignment transferring the temporary T to this tmp
        inline void operator=(const tmp<T>&&);
};


namespace expression
{
    template<class Type>
    struct Expressionable<tmp<Type>>
    :
        public NotExpressionable<Type>
    {};
}


template<class T>
Ostream& operator<<(Ostream& os, const tmp<T>& t);


// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

} // End namespace Foam

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#include "tmpI.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#endif

// ************************************************************************* //