ClassFactory.h

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/*+-------------------------------------------------------------------------+
  |                       MultiVehicle simulator (libmvsim)                 |
  |                                                                         |
  | Copyright (C) 2014-2020  Jose Luis Blanco Claraco                       |
  | Copyright (C) 2017  Borys Tymchenko (Odessa Polytechnic University)     |
  | Distributed under 3-clause BSD License                                  |
  |   See COPYING                                                           |
  +-------------------------------------------------------------------------+ */
#pragma once

#include <mvsim/basic_types.h>
#include <map>
#include <memory>
#include <stdexcept>
#include <string>

namespace mvsim
{
template <class CLASS, typename ARG1 = void, typename ARG2 = int>
class ClassFactory
{
   public:
        using Ptr = std::shared_ptr<CLASS>;

        struct TClassData
        {
                CLASS* (*ptr_factory1)(ARG1);
                CLASS* (*ptr_factory2)(ARG1, ARG2);
                TClassData() : ptr_factory1(nullptr), ptr_factory2(nullptr) {}
        };

        void do_register(const std::string& class_name, const TClassData& data)
        {
                m_classes[class_name] = data;
        }

        Ptr create(const std::string& class_name, ARG1 a1) const
        {
                auto it = m_classes.find(class_name);
                if (it == m_classes.end())
                        throw std::runtime_error(
                                (std::string("ClassFactory: Unknown class ") + class_name)
                                        .c_str());
                if (!it->second.ptr_factory1)
                        throw std::runtime_error(
                                (std::string(
                                         "ClassFactory: factory(1) pointer is nullptr for ") +
                                 class_name)
                                        .c_str());
                return Ptr((*it->second.ptr_factory1)(a1));
        }
        Ptr create(const std::string& class_name, ARG1 a1, ARG2 a2) const
        {
                auto it = m_classes.find(class_name);
                if (it == m_classes.end())
                        throw std::runtime_error(
                                (std::string("ClassFactory: Unknown class ") + class_name)
                                        .c_str());
                if (!it->second.ptr_factory2)
                        throw std::runtime_error(
                                (std::string(
                                         "ClassFactory: factory(2) pointer is nullptr for ") +
                                 class_name)
                                        .c_str());
                return Ptr((*it->second.ptr_factory2)(a1, a2));
        }

   private:
        std::map<std::string, TClassData> m_classes;
};  // namespace mvsim

#define DECLARES_REGISTER_CLASS1(CLASS_NAME, BASE_CLASS, ARG1) \
   public:                                                     \
        static BASE_CLASS* Create(ARG1 a1) { return new CLASS_NAME(a1); }
#define DECLARES_REGISTER_CLASS2(CLASS_NAME, BASE_CLASS, ARG1, ARG2) \
   public:                                                           \
        static BASE_CLASS* Create(ARG1 a1, ARG2 a2)                      \
        {                                                                \
                return new CLASS_NAME(a1, a2);                               \
        }

#define REGISTER_CLASS1(FACTORY_TYPE, FACTORY_OBJ, TEXTUAL_NAME, CLASS_NAME) \
        {                                                                        \
                FACTORY_TYPE::TClassData data;                                       \
                data.ptr_factory1 = &CLASS_NAME::Create;                             \
                FACTORY_OBJ.do_register(TEXTUAL_NAME, data);                         \
        }

#define REGISTER_CLASS2(FACTORY_TYPE, FACTORY_OBJ, TEXTUAL_NAME, CLASS_NAME) \
        {                                                                        \
                FACTORY_TYPE::TClassData data;                                       \
                data.ptr_factory2 = &CLASS_NAME::Create;                             \
                FACTORY_OBJ.do_register(TEXTUAL_NAME, data);                         \
        }
}  // namespace mvsim