mirror of
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256 lines
9.1 KiB
C++
256 lines
9.1 KiB
C++
/*
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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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#ifndef SQLPP_UNION_H
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#define SQLPP_UNION_H
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#include <sqlpp11/union_data.h>
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#include <sqlpp11/union_flags.h>
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#include <sqlpp11/statement_fwd.h>
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#include <sqlpp11/type_traits.h>
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#include <sqlpp11/parameter_list.h>
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#include <sqlpp11/expression.h>
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#include <sqlpp11/interpret_tuple.h>
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#include <sqlpp11/interpretable_list.h>
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#include <sqlpp11/result_row.h>
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#include <sqlpp11/logic.h>
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namespace sqlpp
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{
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struct no_union_t;
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using blank_union_t = statement_t<void, no_union_t>;
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// There is no order by or limit or offset in union, use it as a pseudo table to do that.
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template <bool, typename Union>
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struct union_statement_impl
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{
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using type = statement_t<void, Union, no_union_t>;
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};
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template <typename Union>
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struct union_statement_impl<false, Union>
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{
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using type = bad_statement;
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};
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template <bool Check, typename Union>
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using union_statement_t = typename union_statement_impl<Check, Union>::type;
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// UNION(EXPR)
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template <typename Database, typename Flag, typename Lhs, typename Rhs>
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struct union_t
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{
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using _traits = make_traits<no_value_t, tag::is_union, tag::is_return_value>;
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using _nodes = detail::type_vector<Lhs, Rhs>;
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using _alias_t = struct
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{
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};
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// Data
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using _data_t = union_data_t<Database, Flag, Lhs, Rhs>;
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// Member implementation with data and methods
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template <typename Policies>
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struct _impl_t
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{
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// workaround for msvc bug https://connect.microsoft.com/VisualStudio/Feedback/Details/2173269
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_impl_t() = default;
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_impl_t(const _data_t& data) : _data(data)
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{
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}
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_data_t _data;
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};
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// Base template to be inherited by the statement
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template <typename Policies>
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struct _base_t
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{
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using _data_t = union_data_t<Database, Flag, Lhs, Rhs>;
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// workaround for msvc bug https://connect.microsoft.com/VisualStudio/Feedback/Details/2173269
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template <typename... Args>
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_base_t(Args&&... args)
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: union_{std::forward<Args>(args)...}
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{
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}
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_impl_t<Policies> union_;
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_impl_t<Policies>& operator()()
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{
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return union_;
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}
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const _impl_t<Policies>& operator()() const
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{
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return union_;
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}
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using _selected_columns_t = typename std::decay<decltype(union_._data._lhs.get_selected_columns())>::type;
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_selected_columns_t& get_selected_columns()
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{
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return union_._data._lhs.get_selected_columns();
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}
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const _selected_columns_t& get_selected_columns() const
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{
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return union_._data._lhs.get_selected_columns();
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}
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template <typename T>
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static auto _get_member(T t) -> decltype(t.union_)
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{
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return t.union_;
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}
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using _consistency_check = detail::get_first_if<is_inconsistent_t,
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consistent_t,
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typename Lhs::_consistency_check,
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typename Rhs::_consistency_check>;
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};
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template <typename Statement>
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using _result_methods_t = typename Lhs::template _result_methods_t<Statement>;
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};
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// NO UNION YET
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struct no_union_t
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{
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using _traits = make_traits<no_value_t, tag::is_union>;
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using _nodes = detail::type_vector<>;
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// Data
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using _data_t = no_data_t;
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// Member implementation with data and methods
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template <typename Policies>
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struct _impl_t
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{
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// workaround for msvc bug https://connect.microsoft.com/VisualStudio/Feedback/Details/2173269
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_impl_t() = default;
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_impl_t(const _data_t& data) : _data(data)
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{
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}
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_data_t _data;
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};
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// Base template to be inherited by the statement
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template <typename Policies>
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struct _base_t
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{
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using _data_t = no_data_t;
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// workaround for msvc bug https://connect.microsoft.com/VisualStudio/Feedback/Details/2173269
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template <typename... Args>
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_base_t(Args&&... args)
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: no_union{std::forward<Args>(args)...}
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{
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}
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_impl_t<Policies> no_union;
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_impl_t<Policies>& operator()()
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{
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return no_union;
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}
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const _impl_t<Policies>& operator()() const
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{
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return no_union;
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}
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template <typename T>
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static auto _get_member(T t) -> decltype(t.no_union)
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{
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return t.no_union;
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}
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using _database_t = typename Policies::_database_t;
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// workaround for msvc bug https://connect.microsoft.com/VisualStudio/Feedback/Details/2173269
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// template <typename... T>
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// using _check = logic::all_t<is_statement_t<T>::value...>;
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template <typename... T>
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using _check = typename logic::all<is_statement_t<T>::value...>::type;
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template <typename Check, typename T>
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using _new_statement_t = union_statement_t<Check::value, T>;
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using _consistency_check = consistent_t;
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template <typename Rhs>
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auto union_distinct(Rhs rhs) const
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-> _new_statement_t<_check<Rhs>, union_t<void, union_distinct_t, derived_statement_t<Policies>, Rhs>>
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{
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static_assert(is_statement_t<Rhs>::value, "argument of union call has to be a statement");
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static_assert(has_policy_t<Rhs, is_select_t>::value, "argument of union call has to be a select");
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static_assert(has_result_row_t<Rhs>::value, "argument of a union has to be a complete select statement");
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static_assert(has_result_row_t<derived_statement_t<Policies>>::value,
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"left hand side argument of a union has to be a complete select statement or union");
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using _result_row_t = get_result_row_t<Rhs>;
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static_assert(std::is_same<get_result_row_t<derived_statement_t<Policies>>, _result_row_t>::value,
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"both arguments in a union have to have the same result columns (type and name)");
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static_assert(is_static_result_row_t<_result_row_t>::value, "unions must not have dynamically added columns");
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return _union_impl<void, union_distinct_t>(_check<derived_statement_t<Policies>, Rhs>{}, rhs);
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}
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template <typename Rhs>
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auto union_all(Rhs rhs) const
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-> _new_statement_t<_check<Rhs>, union_t<void, union_all_t, derived_statement_t<Policies>, Rhs>>
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{
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static_assert(is_statement_t<Rhs>::value, "argument of union call has to be a statement");
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static_assert(has_policy_t<Rhs, is_select_t>::value, "argument of union call has to be a select");
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static_assert(has_result_row_t<Rhs>::value, "argument of a union has to be a (complete) select statement");
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static_assert(has_result_row_t<derived_statement_t<Policies>>::value,
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"left hand side argument of a union has to be a (complete) select statement");
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using _result_row_t = get_result_row_t<Rhs>;
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static_assert(std::is_same<get_result_row_t<derived_statement_t<Policies>>, _result_row_t>::value,
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"both arguments in a union have to have the same result columns (type and name)");
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static_assert(is_static_result_row_t<_result_row_t>::value, "unions must not have dynamically added columns");
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return _union_impl<void, union_all_t>(_check<derived_statement_t<Policies>, Rhs>{}, rhs);
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}
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private:
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template <typename Database, typename Flag, typename Rhs>
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auto _union_impl(const std::false_type&, Rhs rhs) const -> bad_statement;
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template <typename Database, typename Flag, typename Rhs>
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auto _union_impl(const std::true_type&, Rhs rhs) const
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-> _new_statement_t<std::true_type, union_t<Database, Flag, derived_statement_t<Policies>, Rhs>>
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{
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return {blank_union_t{},
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union_data_t<Database, Flag, derived_statement_t<Policies>, Rhs>{
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static_cast<const derived_statement_t<Policies>&>(*this), rhs}};
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}
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};
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};
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}
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#endif
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