oraltypes.h

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/**********************************************************************
 * LeechCraft - modular cross-platform feature rich internet client.
 * Copyright (C) 2006-2014  Georg Rudoy
 *
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE or copy at https://www.boost.org/LICENSE_1_0.txt)
 **********************************************************************/
 
#pragma once
 
#include <variant>
#include <type_traits>
#include <boost/fusion/include/at_c.hpp>
#include <boost/fusion/adapted/struct/adapt_struct.hpp>
#include <boost/fusion/include/adapt_struct.hpp>
#include <util/sll/typelist.h>
#include <util/sll/typegetter.h>
 
namespace LC
{
namespace Util
{
namespace oral
{
    struct NoAutogen;
 
    template<typename T, typename Concrete>
    struct IndirectHolderBase
    {
        using value_type = T;
 
        T Val_;
 
        IndirectHolderBase () = default;
 
        IndirectHolderBase (T val)
        : Val_ { val }
        {
        }
 
        template<typename U = T, typename Sub = typename U::value_type>
        IndirectHolderBase (Sub val)
        : Val_ { val }
        {
        }
 
        Concrete& operator= (T val)
        {
            Val_ = val;
            return static_cast<Concrete&> (*this);
        }
 
        operator value_type () const
        {
            return Val_;
        }
 
        const value_type& operator* () const
        {
            return Val_;
        }
 
        const value_type* operator-> () const
        {
            return &Val_;
        }
    };
 
    template<typename T, typename... Tags>
    struct PKey : IndirectHolderBase<T, PKey<T, Tags...>>
    {
        using PKey::IndirectHolderBase::IndirectHolderBase;
    };
 
    template<typename T, typename... Args>
    using PKeyValue_t = typename PKey<T, Args...>::value_type;
 
    template<typename T>
    struct Unique : IndirectHolderBase<T, Unique<T>>
    {
        using Unique::IndirectHolderBase::IndirectHolderBase;
    };
 
    template<typename T>
    using UniqueValue_t = typename Unique<T>::value_type;
 
    template<typename T>
    struct NotNull : IndirectHolderBase<T, NotNull<T>>
    {
        using NotNull::IndirectHolderBase::IndirectHolderBase;
    };
 
    template<typename T>
    using NotNullValue_t = typename NotNull<T>::value_type;
 
    template<typename T>
    using UniqueNotNull = Unique<NotNull<T>>;
 
    namespace detail
    {
        template<typename T>
        struct IsReferencesTarget : std::false_type {};
 
        template<typename U, typename... Tags>
        struct IsReferencesTarget<PKey<U, Tags...>> : std::true_type {};
 
        template<typename U>
        struct IsReferencesTarget<Unique<U>> : std::true_type {};
    }
 
    template<auto Ptr>
    struct References : IndirectHolderBase<typename MemberPtrType_t<Ptr>::value_type, References<Ptr>>
    {
        using member_type = MemberPtrType_t<Ptr>;
        static_assert (detail::IsReferencesTarget<member_type>::value, "References<> element must refer to a PKey<> element");
 
        using References::IndirectHolderBase::IndirectHolderBase;
 
        template<typename T, typename... Tags>
        References (const PKey<T, Tags...>& key)
        : References::IndirectHolderBase (key)
        {
        }
 
        template<typename T, typename... Tags>
        References& operator= (const PKey<T, Tags...>& key)
        {
            this->Val_ = key;
            return *this;
        }
    };
 
    template<auto Ptr>
    using ReferencesValue_t = typename References<Ptr>::value_type;
 
    template<int... Fields>
    struct PrimaryKey;
 
    template<int... Fields>
    struct UniqueSubset;
 
    template<typename... Args>
    using Constraints = Typelist<Args...>;
 
    template<auto... Fields>
    struct Index;
 
    template<typename... Args>
    using Indices = Typelist<Args...>;
 
    template<typename T>
    struct IsIndirect : std::false_type {};
 
    template<typename T, typename... Args>
    struct IsIndirect<PKey<T, Args...>> : std::true_type {};
 
    template<typename T>
    struct IsIndirect<Unique<T>> : std::true_type {};
 
    template<typename T>
    struct IsIndirect<NotNull<T>> : std::true_type {};
 
    template<auto Ptr>
    struct IsIndirect<References<Ptr>> : std::true_type {};
 
    struct InsertAction
    {
        inline static struct DefaultTag {} Default;
        inline static struct IgnoreTag {} Ignore;
 
        struct Replace
        {
            QStringList Fields_;
 
            template<auto... Ptrs>
            struct FieldsType
            {
                operator InsertAction::Replace () const;
            };
 
            template<auto... Ptrs>
            inline static FieldsType<Ptrs...> Fields {};
 
            template<typename Seq>
            struct PKeyType
            {
                operator InsertAction::Replace () const;
            };
 
            template<typename Seq>
            inline static PKeyType<Seq> PKey {};
        };
 
        constexpr static auto StaticCount ()
        {
            return 2;
        }
 
        using ActionSelector_t = std::variant<DefaultTag, IgnoreTag, Replace>;
        ActionSelector_t Selector_;
 
        template<typename Tag>
        InsertAction (Tag tag)
        : Selector_ { tag }
        {
        }
    };
}
}
}