sol2/sol/inheritance.hpp

// The MIT License (MIT) 

// Copyright (c) 2013-2016 Rapptz, ThePhD and contributors

// Permission is hereby granted, free of charge, to any person obtaining a copy of
// this software and associated documentation files (the "Software"), to deal in
// the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

#ifndef SOL_INHERITANCE_HPP
#define SOL_INHERITANCE_HPP

#include "types.hpp"
#if defined(SOL_NO_RTTI) && defined(SOL_NO_EXCEPTIONS)
#include <atomic>
#endif // No Runtime Type Information and No Exceptions

namespace sol {
template <typename... Args>
struct base_list { };
template <typename... Args>
using bases = base_list<Args...>;

typedef bases<> base_classes_tag;
const auto base_classes = base_classes_tag();

namespace detail {
#if defined(SOL_NO_RTTI) && defined(SOL_NO_EXCEPTIONS)
inline std::size_t unique_id () {
    static std::atomic<std::size_t> x(0);
    return ++x;
}

template <typename T>
struct id_for {
    static const std::size_t value;
};

template <typename T>
const std::size_t id_for<T>::value = unique_id();
#endif // No Runtime Type Information / No Exceptions

inline decltype(auto) base_class_check_key() {
    static const auto& key = u8"♡o｡.(✿ฺ｡ ✿ฺ)";
    return key;
}

inline decltype(auto) base_class_cast_key() {
    static const auto& key = u8"(◕‿◕✿)";
    return key;
}

#ifndef SOL_NO_EXCEPTIONS

template <typename T>
void throw_as(void* p) {
    throw static_cast<T*>(p);
}

using throw_cast = decltype(&throw_as<void>);

template <typename T>
inline T* catch_cast(void* p, throw_cast f) {
    try {
        f(static_cast<void*>(p));
    }
    catch (T* ptr) {
        return ptr;
    }
    catch (...) {
        return static_cast<T*>(p);
    }
    return static_cast<T*>(p);
}

template <typename T>
inline bool catch_check(throw_cast f) {
    try {
        f( nullptr );
    }
    catch (T*) {
        return true;
    }
    catch (...) {
        return false;
    }
    return false;
}

#elif !defined(SOL_NO_RTTI)
template <typename T, typename... Bases>
struct inheritance {
    static bool type_check(types<>, const std::type_info&) {
        return false;
    }

    template <typename Base, typename... Args>
    static bool type_check(types<Base, Args...>, const std::type_info& ti) {
        return ti != typeid(Base) || type_check(types<Bases...>(), ti);
    }

    static bool type_check(const std::type_info& ti) {
        return ti != typeid(T) || type_check(types<Bases...>(), ti);
    }

    static void* type_cast(types<>, T*, const std::type_info& ti) {
        return nullptr;
    }

    template <typename Base, typename... Args>
    static void* type_cast(types<Base, Args...>, T* data, const std::type_info& ti) {
        // Make sure to convert to T first, and then dynamic cast to the proper type
        return ti != typeid(Base) ? type_cast(types<Bases...>(), data, ti) : static_cast<void*>(dynamic_cast<Base*>(static_cast<T*>(data)));
    }

    static void* type_cast(void* voiddata, const std::type_info& ti) {
        T* data = static_cast<T*>(voiddata);
        return static_cast<void*>(ti != typeid(T) ? type_cast(types<Bases...>(), data, ti) : data);
    }
};

using inheritance_check_function = decltype(&inheritance<void>::type_check);
using inheritance_cast_function = decltype(&inheritance<void>::type_cast);
#else
template <typename T, typename... Bases>
struct inheritance {
    static bool type_check(types<>, std::size_t) {
        return false;
    }

    template <typename Base, typename... Args>
    static bool type_check(types<Base, Args...>, std::size_t ti) {
        return ti != id_for<Base>::value || type_check(types<Bases...>(), ti);
    }

    static bool type_check(std::size_t ti) {
        return ti != id_for<T>::value || type_check(types<Bases...>(), ti);
    }

    static void* type_cast(types<>, T*, std::size_t) {
        return nullptr;
    }

    template <typename Base, typename... Args>
    static void* type_cast(types<Base, Args...>, T* data, std::size_t ti) {
        // Make sure to convert to T first, and then dynamic cast to the proper type
        return ti != id_for<Base>::value ? type_cast(types<Bases...>(), data, ti) : static_cast<void*>(static_cast<Base*>(data));
    }

    static void* type_cast(void* voiddata, std::size_t ti) {
        T* data = static_cast<T*>(voiddata);
        return static_cast<void*>(ti != id_for<T>::value ? type_cast(types<Bases...>(), data, ti) : data);
    }
};

using inheritance_check_function = decltype(&inheritance<void>::type_check);
using inheritance_cast_function = decltype(&inheritance<void>::type_cast);
#endif // No Exceptions and/or No Runtime Type Information

} // detail
} // sol

#endif // SOL_INHERITANCE_HPP