serialize_meta.hh

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#ifndef SERIALIZE_META_HH
#define SERIALIZE_META_HH

#include "hash_map.hh"
#include "likely.hh"
#include "xxhash.hh"
#include <memory>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <utility>
#include <vector>

namespace openmsx {

template<typename T> struct Creator
{
        template<typename TUPLE>
        std::unique_ptr<T> operator()(TUPLE tuple) {
                auto makeT = [](auto&& ...args) {
                        return std::make_unique<T>(std::forward<decltype(args)>(args)...);
                };
                return std::apply(makeT, tuple);
        }
};


// Polymorphic class loader/saver

// forward declarations
// ClassSaver: used to actually save a class. We also store the name of
//   the class so that the loader knows which concrete class it should load.
template<typename T> struct ClassSaver;
// NonPolymorphicPointerLoader: once we know which concrete type to load,
//   we use the 'normal' class loader to load it.
template<typename T> struct NonPolymorphicPointerLoader;
// Used by PolymorphicInitializer to initialize a concrete type.
template<typename T> struct ClassLoader;

template<typename T> struct PolymorphicConstructorArgs;

template<typename T> struct PolymorphicBaseClass;

template<typename Base> struct MapConstrArgsEmpty
{
        using TUPLEIn = typename PolymorphicConstructorArgs<Base>::type;
        std::tuple<> operator()(const TUPLEIn& /*t*/)
        {
                return std::tuple<>();
        }
};
template<typename Base, typename Derived> struct MapConstrArgsCopy
{
        using TUPLEIn  = typename PolymorphicConstructorArgs<Base>::type;
        using TUPLEOut = typename PolymorphicConstructorArgs<Derived>::type;
        static_assert(std::is_same_v<TUPLEIn, TUPLEOut>,
                      "constructor argument types must match");
        TUPLEOut operator()(const TUPLEIn& t)
        {
                return t;
        }
};

template<typename Base, typename Derived> struct MapConstructorArguments
        : std::conditional_t<std::is_same<std::tuple<>,
                             typename PolymorphicConstructorArgs<Derived>::type>::value,
              MapConstrArgsEmpty<Base>,
              MapConstrArgsCopy<Base, Derived>> {};

template<typename Base> struct BaseClassName;

template<typename Archive> class PolymorphicSaverBase
{
public:
        virtual ~PolymorphicSaverBase() = default;
        virtual void save(Archive& ar, const void* p) const = 0;
};

template<typename Archive> class PolymorphicLoaderBase
{
public:
        virtual ~PolymorphicLoaderBase() = default;
        virtual void* load(Archive& ar, unsigned id, const void* args) const = 0;
};

template<typename Archive> class PolymorphicInitializerBase
{
public:
        virtual ~PolymorphicInitializerBase() = default;
        virtual void init(Archive& ar, void* t, unsigned id) const = 0;
};

template<typename Archive, typename T>
class PolymorphicSaver : public PolymorphicSaverBase<Archive>
{
public:
        explicit PolymorphicSaver(const char* name_)
                : name(name_)
        {
        }
        void save(Archive& ar, const void* v) const override
        {
                using BaseType = typename PolymorphicBaseClass<T>::type;
                auto base = static_cast<const BaseType*>(v);
                auto tp = static_cast<const T*>(base);
                ClassSaver<T> saver;
                saver(ar, *tp, true, name, true); // save id, type, constr-args
        }
private:
        const char* name;
};

template<typename Archive, typename T>
class PolymorphicLoader : public PolymorphicLoaderBase<Archive>
{
public:
        void* load(Archive& ar, unsigned id, const void* args) const override
        {
                using BaseType = typename PolymorphicBaseClass<T>::type;
                using TUPLEIn  = typename PolymorphicConstructorArgs<BaseType>::type;
                using TUPLEOut = typename PolymorphicConstructorArgs<T>::type;
                auto& argsIn = *static_cast<const TUPLEIn*>(args);
                MapConstructorArguments<BaseType, T> mapArgs;
                TUPLEOut argsOut = mapArgs(argsIn);
                NonPolymorphicPointerLoader<T> loader;
                return loader(ar, id, argsOut);
        }
};

void polyInitError(const char* expected, const char* actual);
template<typename Archive, typename T>
class PolymorphicInitializer : public PolymorphicInitializerBase<Archive>
{
public:
        void init(Archive& ar, void* v, unsigned id) const override
        {
                using BaseType = typename PolymorphicBaseClass<T>::type;
                auto base = static_cast<BaseType*>(v);
                if (unlikely(dynamic_cast<T*>(base) != static_cast<T*>(base))) {
                        polyInitError(typeid(T).name(), typeid(*base).name());
                }
                auto t = static_cast<T*>(base);
                ClassLoader<T> loader;
                loader(ar, *t, std::tuple<>(), id);
        }
};


template<typename Archive>
class PolymorphicSaverRegistry
{
public:
        static PolymorphicSaverRegistry& instance();

        template<typename T> void registerClass(const char* name)
        {
                static_assert(std::is_polymorphic_v<T>,
                              "must be a polymorphic type");
                static_assert(!std::is_abstract_v<T>,
                              "can't be an abstract type");
                registerHelper(typeid(T),
                               std::make_unique<PolymorphicSaver<Archive, T>>(name));
        }

        template<typename T> static void save(Archive& ar, T* t)
        {
                save(ar, t, typeid(*t));
        }
        template<typename T> static void save(const char* tag, Archive& ar, T& t)
        {
                save(tag, ar, &t, typeid(t));
        }

private:
        PolymorphicSaverRegistry() = default;
        ~PolymorphicSaverRegistry() = default;
        void registerHelper(const std::type_info& type,
                            std::unique_ptr<PolymorphicSaverBase<Archive>> saver);
        static void save(Archive& ar, const void* t,
                         const std::type_info& typeInfo);
        static void save(const char* tag, Archive& ar, const void* t,
                         const std::type_info& typeInfo);

        std::vector<std::pair<std::type_index,
                              std::unique_ptr<PolymorphicSaverBase<Archive>>>> saverMap;
        bool initialized = false;
};

template<typename Archive>
class PolymorphicLoaderRegistry
{
public:
        static PolymorphicLoaderRegistry& instance();

        template<typename T> void registerClass(const char* name)
        {
                static_assert(std::is_polymorphic_v<T>,
                              "must be a polymorphic type");
                static_assert(!std::is_abstract_v<T>,
                              "can't be an abstract type");
                registerHelper(name,
                               std::make_unique<PolymorphicLoader<Archive, T>>());
        }

        static void* load(Archive& ar, unsigned id, const void* args);

private:
        PolymorphicLoaderRegistry() = default;
        ~PolymorphicLoaderRegistry() = default;
        void registerHelper(
                const char* name,
                std::unique_ptr<PolymorphicLoaderBase<Archive>> loader);

        hash_map<std::string_view, std::unique_ptr<PolymorphicLoaderBase<Archive>>, XXHasher>
                loaderMap;
};

template<typename Archive>
class PolymorphicInitializerRegistry
{
public:
        static PolymorphicInitializerRegistry& instance();

        template<typename T> void registerClass(const char* name)
        {
                static_assert(std::is_polymorphic_v<T>,
                              "must be a polymorphic type");
                static_assert(!std::is_abstract_v<T>,
                              "can't be an abstract type");
                registerHelper(name,
                               std::make_unique<PolymorphicInitializer<Archive, T>>());
        }

        static void init(const char* tag, Archive& ar, void* t);

private:
        PolymorphicInitializerRegistry() = default;
        ~PolymorphicInitializerRegistry() = default;
        void registerHelper(
                const char* name,
                std::unique_ptr<PolymorphicInitializerBase<Archive>> initializer);

        hash_map<std::string_view, std::unique_ptr<PolymorphicInitializerBase<Archive>>, XXHasher>
                initializerMap;
};


template<typename Archive, typename T> struct RegisterSaverHelper
{
        explicit RegisterSaverHelper(const char* name)
        {
                PolymorphicSaverRegistry<Archive>::instance().
                        template registerClass<T>(name);
        }
};
template<typename Archive, typename T> struct RegisterLoaderHelper
{
        explicit RegisterLoaderHelper(const char* name)
        {
                PolymorphicLoaderRegistry<Archive>::instance().
                        template registerClass<T>(name);
        }
};
template<typename Archive, typename T> struct RegisterInitializerHelper
{
        explicit RegisterInitializerHelper(const char* name)
        {
                PolymorphicInitializerRegistry<Archive>::instance().
                        template registerClass<T>(name);
        }
};

#define REGISTER_CONSTRUCTOR_ARGS_0(C) \
template<> struct PolymorphicConstructorArgs<C> \
{ using type = std::tuple<>; };

#define REGISTER_CONSTRUCTOR_ARGS_1(C,T1) \
template<> struct PolymorphicConstructorArgs<C> \
{ using type = std::tuple<T1>; };

#define REGISTER_CONSTRUCTOR_ARGS_2(C,T1,T2) \
template<> struct PolymorphicConstructorArgs<C> \
{ using type = std::tuple<T1,T2>; };

#define REGISTER_CONSTRUCTOR_ARGS_3(C,T1,T2,T3) \
template<> struct PolymorphicConstructorArgs<C> \
{ using type = std::tuple<T1,T2,T3>; };

class MemInputArchive;
class MemOutputArchive;
class XmlInputArchive;
class XmlOutputArchive;

/*#define REGISTER_POLYMORPHIC_CLASS_HELPER(B,C,N) \
static_assert(std::is_base_of_v<B,C>, "must be base and sub class"); \
static RegisterLoaderHelper<TextInputArchive,  C> registerHelper1##C(N); \
static RegisterSaverHelper <TextOutputArchive, C> registerHelper2##C(N); \
static RegisterLoaderHelper<XmlInputArchive,   C> registerHelper3##C(N); \
static RegisterSaverHelper <XmlOutputArchive,  C> registerHelper4##C(N); \
static RegisterLoaderHelper<MemInputArchive,   C> registerHelper5##C(N); \
static RegisterSaverHelper <MemOutputArchive,  C> registerHelper6##C(N); \*/
#define REGISTER_POLYMORPHIC_CLASS_HELPER(B,C,N) \
static_assert(std::is_base_of_v<B,C>, "must be base and sub class"); \
static RegisterLoaderHelper<MemInputArchive,  C> registerHelper3##C(N); \
static RegisterSaverHelper <MemOutputArchive, C> registerHelper4##C(N); \
static RegisterLoaderHelper<XmlInputArchive,  C> registerHelper5##C(N); \
static RegisterSaverHelper <XmlOutputArchive, C> registerHelper6##C(N); \
template<> struct PolymorphicBaseClass<C> { using type = B; };

#define REGISTER_POLYMORPHIC_INITIALIZER_HELPER(B,C,N) \
static_assert(std::is_base_of_v<B,C>, "must be base and sub class"); \
static RegisterInitializerHelper<MemInputArchive,  C> registerHelper3##C(N); \
static RegisterSaverHelper      <MemOutputArchive, C> registerHelper4##C(N); \
static RegisterInitializerHelper<XmlInputArchive,  C> registerHelper5##C(N); \
static RegisterSaverHelper      <XmlOutputArchive, C> registerHelper6##C(N); \
template<> struct PolymorphicBaseClass<C> { using type = B; };

#define REGISTER_BASE_NAME_HELPER(B,N) \
template<> struct BaseClassName<B> \
{ static const char* getName() { static constexpr const char* const name = N; return name; } };

// public macros
//   these are a more convenient way to define specializations of the
//   PolymorphicConstructorArgs and PolymorphicBaseClass classes
#define REGISTER_POLYMORPHIC_CLASS(BASE,CLASS,NAME) \
        REGISTER_POLYMORPHIC_CLASS_HELPER(BASE,CLASS,NAME) \
        REGISTER_CONSTRUCTOR_ARGS_0(CLASS)

#define REGISTER_POLYMORPHIC_CLASS_1(BASE,CLASS,NAME,TYPE1) \
        REGISTER_POLYMORPHIC_CLASS_HELPER(BASE,CLASS,NAME) \
        REGISTER_CONSTRUCTOR_ARGS_1(CLASS,TYPE1)

#define REGISTER_POLYMORPHIC_CLASS_2(BASE,CLASS,NAME,TYPE1,TYPE2) \
        REGISTER_POLYMORPHIC_CLASS_HELPER(BASE,CLASS,NAME) \
        REGISTER_CONSTRUCTOR_ARGS_2(CLASS,TYPE1,TYPE2)

#define REGISTER_POLYMORPHIC_CLASS_3(BASE,CLASS,NAME,TYPE1,TYPE2,TYPE3) \
        REGISTER_POLYMORPHIC_CLASS_HELPER(BASE,CLASS,NAME) \
        REGISTER_CONSTRUCTOR_ARGS_3(CLASS,TYPE1,TYPE2,TYPE3)

#define REGISTER_BASE_CLASS(CLASS,NAME) \
        REGISTER_BASE_NAME_HELPER(CLASS,NAME) \
        REGISTER_CONSTRUCTOR_ARGS_0(CLASS)

#define REGISTER_BASE_CLASS_1(CLASS,NAME,TYPE1) \
        REGISTER_BASE_NAME_HELPER(CLASS,NAME) \
        REGISTER_CONSTRUCTOR_ARGS_1(CLASS,TYPE1)

#define REGISTER_BASE_CLASS_2(CLASS,NAME,TYPE1,TYPE2) \
        REGISTER_BASE_NAME_HELPER(CLASS,NAME) \
        REGISTER_CONSTRUCTOR_ARGS_2(CLASS,TYPE1,TYPE2)

#define REGISTER_BASE_CLASS_3(CLASS,NAME,TYPE1,TYPE2,TYPE3) \
        REGISTER_BASE_NAME_HELPER(CLASS,NAME) \
        REGISTER_CONSTRUCTOR_ARGS_3(CLASS,TYPE1,TYPE2,TYPE3)


#define REGISTER_POLYMORPHIC_INITIALIZER(BASE,CLASS,NAME) \
        REGISTER_POLYMORPHIC_INITIALIZER_HELPER(BASE,CLASS,NAME)


template<typename T> struct SerializeClassVersion
{
        static constexpr unsigned value = 1;
};
#define SERIALIZE_CLASS_VERSION(CLASS, VERSION) \
template<> struct SerializeClassVersion<CLASS> \
{ \
        static constexpr unsigned value = VERSION; \
};

} // namespace openmsx

#endif