ClassFactory.h

/*+-------------------------------------------------------------------------+
  |                       MultiVehicle simulator (libmvsim)                 |
  |                                                                         |
  | Copyright (C) 2014-2026  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)
    {
        classes_[class_name] = data;
    }
 
    Ptr create(const std::string& class_name, ARG1 a1) const
    {
        auto it = classes_.find(class_name);
        if (it == 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 = classes_.find(class_name);
        if (it == 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> 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