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93 lines
3.7 KiB
C++
93 lines
3.7 KiB
C++
#pragma once
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/*
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* Copyright (c) 2013-2015, Roland Bock
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright notice, this
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* list of conditions and the following disclaimer in the documentation and/or
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* other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sqlpp11/type_traits.h>
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#include <type_traits>
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#include <sqlpp11/compat/optional.h>
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namespace sqlpp
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{
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template <typename NameType, typename ValueType, bool CanBeNull>
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struct field_spec_t
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{
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using _traits = make_traits<ValueType,
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tag::is_noop,
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tag_if<tag::can_be_null, CanBeNull>>;
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using _nodes = detail::type_vector<>;
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using _alias_t = NameType;
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using cpp_type = typename std::conditional<CanBeNull,
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sqlpp::compat::optional<typename ValueType::_result_type>,
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typename ValueType::_result_type>::type;
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};
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template <typename Left, typename Right, typename Enable = void>
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struct is_field_compatible
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{
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static constexpr auto value = false;
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};
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template <typename LeftName,
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typename LeftValue,
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bool LeftCanBeNull,
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typename RightName,
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typename RightValue,
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bool RightCanBeNull>
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struct is_field_compatible<field_spec_t<LeftName, LeftValue, LeftCanBeNull>,
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field_spec_t<RightName, RightValue, RightCanBeNull>>
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{
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static constexpr auto value =
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std::is_same<typename LeftName::_name_t, typename RightName::_name_t>::value and
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std::is_same<LeftValue, RightValue>::value and // Same value type
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(LeftCanBeNull or !RightCanBeNull); // The left hand side determines the result row and therefore must allow
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// NULL if the right hand side allows it
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};
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namespace detail
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{
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template <typename Select, typename NamedExpr>
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struct make_field_spec_impl
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{
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static constexpr bool _can_be_null = can_be_null_t<NamedExpr>::value;
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static constexpr bool _depends_on_outer_table =
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detail::make_intersect_set_t<required_tables_of<NamedExpr>,
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typename Select::_used_outer_tables>::size::value > 0;
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using type = field_spec_t<typename NamedExpr::_alias_t,
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value_type_of<NamedExpr>,
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logic::any_t<_can_be_null, _depends_on_outer_table>::value>;
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};
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} // namespace detail
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template <typename Select, typename NamedExpr>
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using make_field_spec_t = typename detail::make_field_spec_impl<Select, NamedExpr>::type;
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} // namespace sqlpp
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