a8/a8/reflect.h

#pragma once

#include <assert.h>
#include <type_traits>

namespace a8
{

    namespace reflect
    {
        class Class;
    }

    struct ReflectibleObject
    {
        a8::reflect::Class *metaclass = NULL;
    };

    namespace reflect
    {

        enum FieldType
        {
           ET_INT32 = 1,
           ET_UINT32 = 2,
           ET_INT64 = 3,
           ET_UINT64 = 4,
           ET_FLOAT = 5,
           ET_DOUBLE = 6,
           ET_STRING = 7,
           ET_CLASS = 8,
           ET_INTERFACE = 9,
        };

        enum FieldSubType
        {
           EST_SIMPLE = 1,
           EST_SIMPLE_POINTER = 2,
           EST_CONTAINRER = 3,
           EST_CONTAINRER_POINTER = 4,
        };

        struct Field;
        class Class;
        typedef bool (*FIELD_FOR_EACH_FUNC)(a8::reflect::Field*, void*, void*);

        struct Field
        {
            const char* field_name = nullptr;
            int type = 0; //int uint int64 uint64 double string class interface class_pointer
            int subtype = 0; //std::vector<x> std::list<x>
            int offset = 0;
            a8::reflect::Class **pp_generic_class = nullptr; //泛型容器类型指针的指针
            void* (*create)() = nullptr;
            void (*destroy)(void*) = nullptr;
            int (*size)(void*) = nullptr;
            void (*for_each)(a8::reflect::Field*, void*, void* , FIELD_FOR_EACH_FUNC) = nullptr;
            char* (*push_back)(void*) = nullptr;
        };

        class Class
        {
        public:
            void* (*create)() = nullptr;
            void (*destroy)(void*) = nullptr;
            void (*copy)(void*, void*) = nullptr;

            Class(const char* classname, int fieldnum, int tag)
            {
                class_name_ = classname;
                tag_ = tag;
                fields_ = new a8::reflect::Field[fieldnum];
                fieldnum_ = fieldnum;
            }

            a8::reflect::Field* GetDeclaredFields() { return fields_; }
            int FieldNum() { return fieldnum_; }
            int ClassId() { return class_id_; }
            int Tag() { return tag_; }
            const char* ClassName() { return class_name_; }

            Field* GetFieldByName(const std::string& name);
            long long GetFieldValueAsInt64(a8::reflect::Field* field, char* p);
            std::string GetFieldValueAsString(a8::reflect::Field* field, char* p);
            void SetSimpleField(
                                int fieldidx,
                                const char* fieldname,
                                int type,
                                int offset
                                );
            void SetField(int fieldidx,
                          const char* fieldname,
                          int type,
                          int subtype,
                          int offset,
                          a8::reflect::Class **pp_generic_class,
                          void* (*create)(),
                          void (*destroy)(void*),
                          int (*size)(void*),
                          void (*for_each)(a8::reflect::Field*, void*, void*, FIELD_FOR_EACH_FUNC),
                          char* (*push_back)(void*)
                          );
            int GetFieldIdx(int offset);
        private:
            int class_id_ = 0;
            int tag_ = 0;
            int fieldnum_ = 0;
            const char* class_name_ = nullptr;
            a8::reflect::Field* fields_ = nullptr;
        };

        template <typename T>
        static void* _create()
        {
            return (void*) new T();
        }

        template <typename T>
        static void _destroy(void* instance)
        {
          T* p = (T*)instance;
          delete p;
        }

        template <typename T>
        static void _copy(void* a, void* b)
        {
            *(T*)a = *(T*)b;
        }

        template <typename T>
        static int _size(void* instance)
        {
            T* p = (T*)instance;
            return p->size();
        }

        template <typename T>
        static void _for_each(a8::reflect::Field* field, void* instance, void* userdata,
                              FIELD_FOR_EACH_FUNC callback)
        {
            T* p = (T*)instance;
            for (auto &itr : *p) {
                if (callback && !callback(field, userdata, (void*)&itr)) {
                    break;
                }
            }
        }

        template <typename T>
        static char* _push_back(void* instance)
        {
            T* p = (T*)instance;
            return (char*)&a8::FastAppend(*p);
        }

        template <typename T>
        inline a8::reflect::Class** get_pp_generic_class(a8::ReflectibleObject& obj)
        {
            return &T::__metaclass;
        }

        template <typename T>
        inline a8::reflect::Class** get_pp_generic_class(const T& obj)
        {
            return nullptr;
        }

    }
}

#define my_offsetof2(TYPE, MEMBER)                              \
    ((size_t)((char *)&(((TYPE *)0x10)->MEMBER) - (char*)0x10))

#define container_of2(ptr, type, member) ({                             \
            const typeof( ((type *)0)->member ) *__mptr = (ptr);        \
            (type *)( (char *)__mptr - my_offsetof2(type,member) );})

#define BEGIN_MSG_CLASS(classname, fieldnum)                            \
    {                                                                   \
    a8::reflect::Class *metaclass = new a8::reflect::Class(#classname, fieldnum, 0); \
    metaclass->create =&a8::reflect::_create<classname>;               \
    metaclass->destroy =&a8::reflect::_destroy<classname>;             \
    metaclass->copy =&a8::reflect::_copy<classname>;                   \
    classname::__metaclass = metaclass;                                 \
    classname p;

#define END_MSG_CLASS()                         \
    }

#define BEGIN_MFMSG_CLASS(classname, fieldnum)                          \
    {                                                                   \
    a8::reflect::Class *metaclass = new a8::reflect::Class(#classname, fieldnum, 0); \
    metaclass->create =&a8::reflect::_create<classname>;               \
    metaclass->destroy =&a8::reflect::_destroy<classname>;             \
    metaclass->copy =&a8::reflect::_copy<classname>;                   \
    /*classname::__metaclass = metaclass;*/                             \
    /*assert(classname::CLSID < 1024);*/                                \
    /*s_mfclass_metaclasses[0] = metaclass;*/                           \
    classname p;

#define END_MFMSG_CLASS()                       \
    }

#define DEFINE_SIMPLE_FIELD(fieldidx, fieldname, type)          \
    metaclass->SetField(fieldidx,                               \
                        #fieldname,                             \
                        type,                                   \
                        a8::reflect::EST_SIMPLE,                \
                        my_offsetof2(decltype(p), fieldname),   \
                        NULL,                                   \
                        NULL,                                   \
                        NULL,                                   \
                        NULL,                                   \
                        NULL,                                   \
                        NULL);

#define DEFINE_SIMPLE_POINTER_FIELD(fieldidx, fieldname, type)          \
    metaclass->SetField(fieldidx,                               \
                        #fieldname,                             \
                        type,                                   \
                        a8::reflect::EST_SIMPLE_POINTER,        \
                        my_offsetof2(decltype(p), fieldname),   \
                        NULL,                                   \
                        NULL,                                   \
                        NULL,                                   \
                        NULL,                                   \
                        NULL,                                   \
                        NULL);

#define DEFINE_CONTAINRER_FIELD(fieldidx, fieldname, type)                  \
    metaclass->SetField(fieldidx,                                       \
                        #fieldname,                                     \
                        type,                                           \
                        a8::reflect::EST_CONTAINRER,                        \
                        my_offsetof2(decltype(p), fieldname),           \
                        a8::reflect::get_pp_generic_class<decltype(p.fieldname)>(p.fieldname), \
                        &a8::reflect::_create<decltype(p.fieldname)>,   \
                        &a8::reflect::_destroy<decltype(p.fieldname)>,  \
                        &a8::reflect::_size<decltype(p.fieldname)>,     \
                        &a8::reflect::_for_each<decltype(p.fieldname)> , \
                        &a8::reflect::_push_back<decltype(p.fieldname)> \
                        );

#define DEFINE_CONTAINRER_POINTER_FIELD(fieldidx, fieldname, type)                  \
    metaclass->SetField(fieldidx,                                       \
                        #fieldname,                                     \
                        type,                                           \
                        a8::reflect::EST_CONTAINRER_POINTER,            \
                        my_offsetof2(decltype(p), fieldname),           \
                        a8::reflect::get_pp_generic_class<decltype(p.fieldname)>(p.fieldname), \
                        &a8::reflect::_create<decltype(p.fieldname)>,   \
                        &a8::reflect::_destroy<decltype(p.fieldname)>,  \
                        &a8::reflect::_size<decltype(p.fieldname)>,     \
                        &a8::reflect::_for_each<decltype(p.fieldname)> , \
                        &a8::reflect::_push_back<decltype(p.fieldname)> \
                        );