mirror of
https://github.com/rbock/sqlpp11.git
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407 lines
13 KiB
C++
407 lines
13 KiB
C++
/*
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* Copyright (c) 2013-2014, 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_SELECT_COLUMN_LIST_H
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#define SQLPP_SELECT_COLUMN_LIST_H
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#include <tuple>
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#include <sqlpp11/result_row.h>
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#include <sqlpp11/table.h>
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#include <sqlpp11/no_value.h>
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#include <sqlpp11/field_spec.h>
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#include <sqlpp11/expression_fwd.h>
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#include <sqlpp11/select_pseudo_table.h>
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#include <sqlpp11/named_interpretable.h>
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#include <sqlpp11/interpret_tuple.h>
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#include <sqlpp11/policy_update.h>
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#include <sqlpp11/detail/type_set.h>
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#include <sqlpp11/detail/copy_tuple_args.h>
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namespace sqlpp
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{
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namespace detail
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{
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template<typename... Columns>
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struct select_traits
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{
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using _traits = make_traits<no_value_t, tag::is_select_column_list, tag::is_return_value>;
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struct _name_t {};
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};
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template<typename Column>
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struct select_traits<Column>
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{
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using _traits = make_traits<value_type_of<Column>, tag::is_select_column_list, tag::is_return_value, tag::is_expression, tag::is_named_expression>;
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using _name_t = typename Column::_name_t;
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};
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}
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template<typename Db>
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struct dynamic_select_column_list
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{
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using _names_t = std::vector<std::string>;
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std::vector<named_interpretable_t<Db>> _dynamic_columns;
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_names_t _dynamic_expression_names;
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template<typename Expr>
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void emplace_back(Expr expr)
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{
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_dynamic_expression_names.push_back(Expr::_name_t::_get_name());
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_dynamic_columns.emplace_back(expr);
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}
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bool empty() const
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{
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return _dynamic_columns.empty();
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}
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};
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template<>
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struct dynamic_select_column_list<void>
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{
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struct _names_t
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{
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static constexpr size_t size() { return 0; }
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};
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_names_t _dynamic_expression_names;
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static constexpr bool empty()
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{
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return true;
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}
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};
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template<typename Context, typename Db>
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struct serializer_t<Context, dynamic_select_column_list<Db>>
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{
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using T = dynamic_select_column_list<Db>;
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static Context& _(const T& t, Context& context)
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{
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bool first = true;
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for (const auto column : t._dynamic_columns)
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{
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if (first)
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first = false;
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else
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context << ',';
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serialize(column, context);
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}
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return context;
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}
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};
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template<typename Context>
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struct serializer_t<Context, dynamic_select_column_list<void>>
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{
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using T = dynamic_select_column_list<void>;
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static Context& _(const T& t, Context& context)
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{
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return context;
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}
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};
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// SELECTED COLUMNS DATA
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template<typename Database, typename... Columns>
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struct select_column_list_data_t
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{
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select_column_list_data_t(Columns... columns):
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_columns(columns...)
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{}
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select_column_list_data_t(std::tuple<Columns...> columns):
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_columns(columns)
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{}
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select_column_list_data_t(const select_column_list_data_t&) = default;
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select_column_list_data_t(select_column_list_data_t&&) = default;
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select_column_list_data_t& operator=(const select_column_list_data_t&) = default;
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select_column_list_data_t& operator=(select_column_list_data_t&&) = default;
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~select_column_list_data_t() = default;
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std::tuple<Columns...> _columns;
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dynamic_select_column_list<Database> _dynamic_columns;
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};
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// SELECTED COLUMNS
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template<typename Database, typename... Columns>
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struct select_column_list_t
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{
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using _traits = typename ::sqlpp::detail::select_traits<Columns...>::_traits;
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using _recursive_traits = make_recursive_traits<Columns...>;
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using _name_t = typename ::sqlpp::detail::select_traits<Columns...>::_name_t;
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using _is_dynamic = is_database<Database>;
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static_assert(_is_dynamic::value or sizeof...(Columns), "at least one select expression required");
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static_assert(not ::sqlpp::detail::has_duplicates<Columns...>::value, "at least one duplicate argument detected");
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static_assert(::sqlpp::detail::all_t<(is_named_expression_t<Columns>::value or is_multi_column_t<Columns>::value)...>::value, "at least one argument is not a named expression");
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static_assert(not ::sqlpp::detail::has_duplicates<typename Columns::_name_t...>::value, "at least one duplicate name detected");
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struct _column_type {};
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// Data
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using _data_t = select_column_list_data_t<Database, Columns...>;
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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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template<typename NamedExpression>
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void add_ntc(NamedExpression namedExpression)
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{
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add<NamedExpression, std::false_type>(namedExpression);
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}
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template<typename NamedExpression, typename TableCheckRequired = std::true_type>
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void add(NamedExpression namedExpression)
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{
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static_assert(_is_dynamic::value, "selected_columns::add() can only be called for dynamic_column");
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static_assert(is_named_expression_t<NamedExpression>::value, "invalid named expression argument in selected_columns::add()");
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static_assert(TableCheckRequired::value or Policies::template _no_unknown_tables<NamedExpression>::value, "named expression uses tables unknown to this statement in selected_columns::add()");
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using column_names = ::sqlpp::detail::make_type_set_t<typename Columns::_name_t...>;
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static_assert(not ::sqlpp::detail::is_element_of<typename NamedExpression::_name_t, column_names>::value, "a column of this name is present in the select already");
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using ok = ::sqlpp::detail::all_t<
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_is_dynamic::value,
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is_named_expression_t<NamedExpression>::value
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>;
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_add_impl(namedExpression, ok()); // dispatch to prevent compile messages after the static_assert
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}
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//private:
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template<typename NamedExpression>
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void _add_impl(NamedExpression namedExpression, const std::true_type&)
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{
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return _data._dynamic_columns.emplace_back(namedExpression);
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}
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template<typename NamedExpression>
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void _add_column_impl(NamedExpression namedExpression, const std::false_type&);
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public:
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_data_t _data;
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};
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// Member template for adding the named member to a statement
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template<typename Policies>
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struct _member_t
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{
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using _data_t = select_column_list_data_t<Database, Columns...>;
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_impl_t<Policies> selected_columns;
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_impl_t<Policies>& operator()() { return selected_columns; }
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const _impl_t<Policies>& operator()() const { return selected_columns; }
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template<typename T>
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static auto _get_member(T t) -> decltype(t.selected_columns)
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{
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return t.selected_columns;
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}
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};
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// Additional methods for the statement
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template<typename Policies>
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struct _methods_t
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{
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static void _check_consistency() {}
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};
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// Result methods
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template<typename Policies>
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struct _result_methods_t
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{
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using _statement_t = typename Policies::_statement_t;
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const _statement_t& _get_statement() const
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{
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return static_cast<const _statement_t&>(*this);
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}
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template<typename Db, typename Column>
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struct _deferred_field_t
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{
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using type = make_field_spec_t<_statement_t, Column>;
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};
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template<typename Db, typename Column>
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using _field_t = typename _deferred_field_t<Db, Column>::type;
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template<typename Db>
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using _result_row_t = typename std::conditional<_is_dynamic::value,
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dynamic_result_row_t<Db, _field_t<Db, Columns>...>,
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result_row_t<Db, _field_t<Db, Columns>...>>::type;
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using _dynamic_names_t = typename dynamic_select_column_list<Database>::_names_t;
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template<typename AliasProvider>
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struct _deferred_table_t
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{
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using table = select_pseudo_table_t<_statement_t, Columns...>;
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using alias = typename table::template _alias_t<AliasProvider>;
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};
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template<typename AliasProvider>
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using _table_t = typename _deferred_table_t<AliasProvider>::table;
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template<typename AliasProvider>
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using _alias_t = typename _deferred_table_t<AliasProvider>::alias;
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template<typename AliasProvider>
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_alias_t<AliasProvider> as(const AliasProvider& aliasProvider) const
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{
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static_assert(Policies::_can_be_used_as_table::value, "statement cannot be used as table, e.g. due to missing tables");
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static_assert(::sqlpp::detail::none_t<is_multi_column_t<Columns>::value...>::value, "cannot use multi-columns in sub selects");
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return _table_t<AliasProvider>(_get_statement()).as(aliasProvider);
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}
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const _dynamic_names_t& get_dynamic_names() const
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{
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return _get_statement().selected_columns._data._dynamic_columns._dynamic_expression_names;
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}
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size_t get_no_of_result_columns() const
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{
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return sizeof...(Columns) + get_dynamic_names().size();
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}
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// Execute
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template<typename Db>
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auto _run(Db& db) const
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-> result_t<decltype(db.select(this->_get_statement())), _result_row_t<Db>>
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{
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_statement_t::_check_consistency();
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static_assert(_statement_t::_get_static_no_of_parameters() == 0, "cannot run select directly with parameters, use prepare instead");
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return {db.select(_get_statement()), get_dynamic_names()};
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}
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// Prepare
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template<typename Db>
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auto _prepare(Db& db) const
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-> prepared_select_t<Db, _statement_t>
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{
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_statement_t::_check_consistency();
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return {{}, get_dynamic_names(), db.prepare_select(_get_statement())};
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}
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};
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};
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namespace detail
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{
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template<typename Database, typename... Columns>
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using make_select_column_list_t =
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copy_tuple_args_t<select_column_list_t, Database,
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decltype(std::tuple_cat(as_tuple<Columns>::_(std::declval<Columns>())...))>;
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}
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struct no_select_column_list_t
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{
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using _traits = make_traits<no_value_t, ::sqlpp::tag::is_noop, ::sqlpp::tag::is_missing>;
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using _recursive_traits = make_recursive_traits<>;
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struct _name_t {};
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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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_data_t _data;
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};
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// Member template for adding the named member to a statement
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template<typename Policies>
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struct _member_t
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{
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using _data_t = no_data_t;
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_impl_t<Policies> no_selected_columns;
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_impl_t<Policies>& operator()() { return no_selected_columns; }
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const _impl_t<Policies>& operator()() const { return no_selected_columns; }
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template<typename T>
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static auto _get_member(T t) -> decltype(t.no_selected_columns)
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{
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return t.no_selected_columns;
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}
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};
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// Additional methods for the statement
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template<typename Policies>
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struct _methods_t
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{
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using _database_t = typename Policies::_database_t;
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template<typename T>
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using _new_statement_t = typename Policies::template _new_statement_t<no_select_column_list_t, T>;
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static void _check_consistency() {}
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template<typename... Args>
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auto columns(Args... args)
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-> _new_statement_t<::sqlpp::detail::make_select_column_list_t<void, Args...>>
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{
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return { *static_cast<typename Policies::_statement_t*>(this), typename ::sqlpp::detail::make_select_column_list_t<void, Args...>::_data_t{std::tuple_cat(::sqlpp::detail::as_tuple<Args>::_(args)...)} };
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}
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template<typename... Args>
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auto dynamic_columns(Args... args)
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-> _new_statement_t<::sqlpp::detail::make_select_column_list_t<_database_t, Args...>>
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{
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static_assert(not std::is_same<_database_t, void>::value, "dynamic_columns must not be called in a static statement");
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return { *static_cast<typename Policies::_statement_t*>(this), typename ::sqlpp::detail::make_select_column_list_t<_database_t, Args...>::_data_t{std::tuple_cat(::sqlpp::detail::as_tuple<Args>::_(args)...)} };
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}
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};
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};
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// Interpreters
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template<typename Context, typename Database, typename... Columns>
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struct serializer_t<Context, select_column_list_data_t<Database, Columns...>>
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{
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using T = select_column_list_data_t<Database, Columns...>;
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static Context& _(const T& t, Context& context)
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{
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interpret_tuple(t._columns, ',', context);
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if (sizeof...(Columns) and not t._dynamic_columns.empty())
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context << ',';
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serialize(t._dynamic_columns, context);
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return context;
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}
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};
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}
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#endif
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