cpphibernate/include/cpphibernate/driver/mariadb/classes/fields/fields.inl

#pragma once

#include "field.h"

namespace cpphibernate {
namespace mariadb {

    namespace __impl
    {

        /* fields_builder */

        template<typename X, typename>
        struct fields_builder
        {
            template<typename... T_args>
            static constexpr decltype(auto) apply(T_args&&... args)
                { static_assert(sizeof...(args) == -1, "Invalid parameters for mariadb::make_fields(...)!"); }
        };

        template<typename T_owner, typename T_schema, typename T_table>
        struct fields_builder<
            mp::list<T_owner, T_schema, T_table>,
            mp::enable_if_t<
                    mp::is_same_v<table_t, mp::decay_t<T_owner>>
                &&  schema::is_schema_v<mp::decay_t<T_schema>>
                &&  schema::is_table_v<mp::decay_t<T_table>>>>
        {
            template<typename T_index>
            static constexpr void emplace(
                fields_t&       result,
                const table_t&  owner,
                const T_schema& schema,
                const T_table&  table,
                T_index&&       index)
            {
                result.emplace_back(make_field(owner, schema, table, table.fields[index]));
            }

            template<size_t... I>
            static auto helper(
                const table_t& owner,
                const T_schema& schema,
                const T_table& table,
                std::index_sequence<I...>&&)
            {
                fields_t ret;
                int dummy[] = { 0, (emplace(ret, owner, schema, table, hana::size_c<I>), void(), 0)... };
                (void) dummy;
                return ret;
            }

            static constexpr decltype(auto) apply(
                const table_t& owner, const T_schema& schema, const T_table& table)
            {
                using size = decltype(hana::size(table.fields));
                return helper(owner, schema, table, std::make_index_sequence<size::value> { });
            }
        };

    }

} }