mysql/impl/with_params.hpp

0001 //
0002 // Copyright (c) 2019-2025 Ruben Perez Hidalgo (rubenperez038 at gmail dot com)
0003 //
0004 // Distributed under the Boost Software License, Version 1.0. (See accompanying
0005 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 //
0007
0008 #ifndef BOOST_MYSQL_IMPL_WITH_PARAMS_HPP
0009 #define BOOST_MYSQL_IMPL_WITH_PARAMS_HPP
0010
0011 #pragma once
0012
0013 #include <boost/mysql/constant_string_view.hpp>
0014 #include <boost/mysql/field_view.hpp>
0015 #include <boost/mysql/format_sql.hpp>
0016 #include <boost/mysql/with_params.hpp>
0017
0018 #include <boost/mysql/detail/any_execution_request.hpp>
0019
0020 #include <boost/core/ignore_unused.hpp>
0021 #include <boost/core/span.hpp>
0022 #include <boost/mp11/integer_sequence.hpp>
0023
0024 // Execution request traits
0025 namespace boost {
0026 namespace mysql {
0027 namespace detail {
0028
0029 template <std::size_t N>
0030 struct with_params_proxy
0031 {
0032     constant_string_view query;
0033     std::array<format_arg, N> args;
0034
0035     operator detail::any_execution_request() const { return any_execution_request({query, args}); }
0036 };
0037
0038 template <class... T>
0039 struct execution_request_traits<with_params_t<T...>>
0040 {
0041     template <class WithParamsType, std::size_t... I>
0042     static with_params_proxy<sizeof...(T)> make_request_impl(WithParamsType&& input, mp11::index_sequence<I...>)
0043     {
0044         boost::ignore_unused(input);  // MSVC gets confused for tuples of size 0
0045         // clang-format off
0046         return {
0047             input.query,
0048             {{
0049                 {
0050                     string_view(),
0051                     formattable_ref(std::get<I>(std::forward<WithParamsType>(input).args))
0052                 }...
0053             }}
0054         };
0055         // clang-format on
0056     }
0057
0058     // Allow the value category of the object to be deduced
0059     template <class WithParamsType>
0060     static with_params_proxy<sizeof...(T)> make_request(WithParamsType&& input, std::vector<field_view>&)
0061     {
0062         return make_request_impl(
0063             std::forward<WithParamsType>(input),
0064             mp11::make_index_sequence<sizeof...(T)>()
0065         );
0066     }
0067 };
0068
0069 // Old MSVCs fail to process the above when sizeof...(T) is zero
0070 template <>
0071 struct execution_request_traits<with_params_t<>>
0072 {
0073     static any_execution_request make_request(with_params_t<> input, std::vector<field_view>&)
0074     {
0075         return any_execution_request({input.query, span<format_arg>{}});
0076     }
0077 };
0078
0079 }  // namespace detail
0080 }  // namespace mysql
0081 }  // namespace boost
0082
0083 #endif