inheritancetraits.h

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// SPDX-FileCopyrightText: Copyright (C) 2015 swift Project Community / Contributors
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-swift-pilot-client-1
 
 
#ifndef SWIFT_MISC_INHERITANCE_TRAITS_H
#define SWIFT_MISC_INHERITANCE_TRAITS_H
 
#include <type_traits>
 
template <typename T>
struct QMetaTypeId;
 
namespace swift::misc
{
    class CPropertyIndexRef;
 
    template <typename T, typename = std::void_t<>>
    struct TBaseOf
    {
        using type = void; 
    };
    template <typename T>
    struct TBaseOf<T, std::void_t<typename T::base_type>>
    {
        using type = typename T::base_type; 
    };
 
    template <typename T>
    inline constexpr bool THasMetaBaseV = QMetaTypeId<typename TBaseOf<T>::type>::Defined;
 
    template <class T>
    struct TMetaBaseOf
    {
        using type = std::conditional_t<THasMetaBaseV<T>, typename TBaseOf<T>::type, void>;
    };
 
    template <typename T, typename = std::void_t<>>
    struct TIndexBaseOf
    {
        using type = void; 
    };
    template <typename T>
    struct TIndexBaseOf<T, std::void_t<decltype(std::declval<typename T::base_type>().propertyByIndex(
                               std::declval<CPropertyIndexRef>()))>>
    {
        using type = typename T::base_type; 
    };
 
    template <class T>
    using TBaseOfT = typename TBaseOf<T>::type;
 
    template <class T>
    using TMetaBaseOfT = typename TMetaBaseOf<T>::type;
 
    template <class T>
    using TIndexBaseOfT = typename TIndexBaseOf<T>::type;
} // namespace swift::misc
 
#endif // SWIFT_MISC_INHERITANCE_TRAITS_H