transitive_ptr.h

/*****************************************************/
/* lean Tags                    (c) Tobias Zirr 2011 */
/*****************************************************/

#ifndef LEAN_TAGS_TRANSITIVE_PTR
#define LEAN_TAGS_TRANSITIVE_PTR

#include "../lean.h"
#include "../meta/conditional.h"

namespace lean
{
namespace tags
{

template <class Type, bool Immutable = false>
class transitive_ptr
{
private:
    typename lean::conditional_type<Immutable, Type *const, Type*>::type m_object;

public:
    typedef Type object_type;
    typedef object_type* value_type;
    typedef const object_type* const_value_type;

    LEAN_INLINE transitive_ptr(object_type *object = nullptr)
        : m_object( object ) { };
    template <class Type2>
    LEAN_INLINE transitive_ptr(Type2 *object)
        : m_object( object ) { };
    template <class Type2>
    LEAN_INLINE transitive_ptr(const transitive_ptr<Type2> &right)
        : m_object( right.get() ) { };
    
    transitive_ptr& operator =(object_type *object)
    {
        m_object = object;
        return *this;
    }
    template <class Type2>
    transitive_ptr& operator =(const transitive_ptr<Type2> &right)
    {
        return (*this = right.get());
    }

    LEAN_INLINE const value_type& get() { return m_object; }
    LEAN_INLINE const const_value_type& get() const { return m_object; }

    LEAN_INLINE object_type& operator *() { return *get(); }
    LEAN_INLINE const object_type& operator *() const { return *get(); }
    
    LEAN_INLINE object_type* operator ->() { return get(); }
    LEAN_INLINE const object_type* operator ->() const { return get(); }

    LEAN_INLINE operator value_type() { return get(); }
    LEAN_INLINE operator const_value_type() const { return get(); }
};

} // namespace

using tags::transitive_ptr;

} // namespace

#endif