poly_ptr_ptr.h

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/* +---------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)               |
   |                          http://www.mrpt.org/                             |
   |                                                                           |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file        |
   | See: http://www.mrpt.org/Authors - All rights reserved.                   |
   | Released under BSD License. See details in http://www.mrpt.org/License    |
   +---------------------------------------------------------------------------+ */
#pragma once

#include <stdexcept>
#include <cstdlib>

namespace mrpt
{
        namespace utils
        {
                /** \addtogroup stlext_grp
                  * @{ */

                /** Wrapper to a smart pointer to polymorphic classes, capable of handling 
                * copy operator, etc. making deep copies.
                * Example use: `poly_ptr_ptr<mrpt::poses::CPosePDFPtr>`
                * \sa copy_ptr<T>
                */
                template <typename T>
                class poly_ptr_ptr
                {
                public:
                        /** Ctor from a smart pointer; makes deep copy. */
                        poly_ptr_ptr(const T &ptr) {
                                m_smartptr = ptr;
                                m_smartptr.make_unique();
                        }
                        /** Default ctor; init to nullptr. */
                        poly_ptr_ptr() {}
                        /** copy ctor: makes a copy of the object via `clone()` */
                        poly_ptr_ptr(const poly_ptr_ptr<T> & o) {
                                m_smartptr = o.m_smartptr;
                                m_smartptr.make_unique();
                        }
                        poly_ptr_ptr<T> & operator =(const poly_ptr_ptr<T> &o) {
                                if (this == &o) return *this;
                                m_smartptr = o.m_smartptr;
                                m_smartptr.make_unique();
                                return *this;
                        }
                        poly_ptr_ptr<T> & operator =(const T &o_ptr) {
                                m_smartptr = o_ptr;
                                m_smartptr.make_unique();
                                return *this;
                        }
#if (__cplusplus>199711L)
                        /** move ctor */
                        poly_ptr_ptr(poly_ptr_ptr && o) {
                                m_smartptr = o.m_smartptr;
                                o.m_smartptr.clear_unique();
                        }
                        /** move operator */
                        poly_ptr_ptr<T> &operator =(poly_ptr_ptr<T> && o) {
                                if (this == &o) return *this;
                                m_smartptr = o.m_smartptr;
                                o.m_smartptr.clear_unique();
                                return *this;
                        }
#endif
                        ~poly_ptr_ptr() {}

                        typename T::value_type * pointer() {
                                if (m_smartptr) return m_smartptr.pointer();
                                else throw std::runtime_error("dereferencing NULL poly_ptr_ptr");
                        }
                        const typename T::value_type * pointer() const {
                                if (m_smartptr) return m_smartptr.pointer();
                                else throw std::runtime_error("dereferencing NULL poly_ptr_ptr");
                        }

                        typename T::value_type * operator->() { return pointer(); }
                        const typename T::value_type * operator->() const { return pointer(); }

                        typename T::value_type& operator*(void) { return *pointer(); }
                        const typename T::value_type& operator*(void) const { return *pointer(); }

                        operator bool() const { return m_smartptr.present(); }
                        bool operator!(void) const { return !m_smartptr.present(); }

                        const T & get_ptr() const { return m_smartptr; }
                        T & get_ptr() { return m_smartptr; }

                        void clear_unique() { m_smartptr.clear_unique();  }
                private:
                        T m_smartptr;
                };

                /** @} */  // end of grouping
        } // End of namespace
} // End of namespace