sqlpp11/include/sqlpp11/using.h

/*
 * Copyright (c) 2013-2014, Roland Bock
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * 
 *   Redistributions of source code must retain the above copyright notice, this
 *   list of conditions and the following disclaimer.
 * 
 *   Redistributions in binary form must reproduce the above copyright notice, this
 *   list of conditions and the following disclaimer in the documentation and/or
 *   other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef SQLPP_USING_H
#define SQLPP_USING_H

#include <sqlpp11/type_traits.h>
#include <sqlpp11/interpretable_list.h>
#include <sqlpp11/interpret_tuple.h>
#include <sqlpp11/detail/type_set.h>
#include <sqlpp11/policy_update.h>

namespace sqlpp
{
	// USING DATA
	template<typename Database, typename... Tables>
		struct using_data_t
		{
			using_data_t(Tables... tables):
				_tables(tables...)
			{}

			using_data_t(const using_data_t&) = default;
			using_data_t(using_data_t&&) = default;
			using_data_t& operator=(const using_data_t&) = default;
			using_data_t& operator=(using_data_t&&) = default;
			~using_data_t() = default;

			std::tuple<Tables...> _tables;
			interpretable_list_t<Database> _dynamic_tables;
		};

	// USING
	template<typename Database, typename... Tables>
		struct using_t
		{
			using _traits = make_traits<no_value_t, ::sqlpp::tag::is_using_>;
			using _recursive_traits = make_recursive_traits<Tables...>;

			using _is_dynamic = is_database<Database>;

			static_assert(_is_dynamic::value or sizeof...(Tables), "at least one table argument required in using()");

			static_assert(not ::sqlpp::detail::has_duplicates<Tables...>::value, "at least one duplicate argument detected in using()");

			static_assert(::sqlpp::detail::all_t<is_table_t<Tables>::value...>::value, "at least one argument is not an table in using()");

			// Data
			using _data_t = using_data_t<Database, Tables...>;

			// Member implementation with data and methods
			template <typename Policies>
				struct _impl_t
				{
					template<typename Table>
						void add(Table table)
						{
							static_assert(_is_dynamic::value, "add must not be called for static using()");
							static_assert(is_table_t<Table>::value, "invalid table argument in add()");

							using ok = ::sqlpp::detail::all_t<_is_dynamic::value, is_table_t<Table>::value>;

							_add_impl(table, ok()); // dispatch to prevent compile messages after the static_assert
						}

				private:
					template<typename Table>
						void _add_impl(Table table, const std::true_type&)
						{
							return _data._dynamic_tables.emplace_back(table);
						}

					template<typename Table>
						void _add_impl(Table table, const std::false_type&);

				public:
					_data_t _data;
				};

			// Member template for adding the named member to a statement
			template<typename Policies>
				struct _member_t
				{
					using _data_t = using_data_t<Database, Tables...>;

					_impl_t<Policies> using_;
					_impl_t<Policies>& operator()() { return using_; }
					const _impl_t<Policies>& operator()() const { return using_; }

					template<typename T>
						static auto _get_member(T t) -> decltype(t.using_)
						{
							return t.using_;
						}
				};

			// Additional methods for the statement
			template<typename Policies>
				struct _methods_t
				{
					static void _check_consistency() {}
				};
		};

	// NO USING YET
	struct no_using_t
	{
		using _traits = make_traits<no_value_t, ::sqlpp::tag::is_where>;
		using _recursive_traits = make_recursive_traits<>;

		// Data
		using _data_t = no_data_t;

		// Member implementation with data and methods
		template<typename Policies>
			struct _impl_t
			{
				_data_t _data;
			};

		// Member template for adding the named member to a statement
		template<typename Policies>
			struct _member_t
			{
				using _data_t = no_data_t;

				_impl_t<Policies> no_using;
				_impl_t<Policies>& operator()() { return no_using; }
				const _impl_t<Policies>& operator()() const { return no_using; }

				template<typename T>
					static auto _get_member(T t) -> decltype(t.no_using)
					{
						return t.no_using;
					}
			};

		template<typename Policies>
			struct _methods_t
			{
				using _database_t = typename Policies::_database_t;
				template<typename T>
					using _new_statement_t = new_statement<Policies, no_using_t, T>;

				static void _check_consistency() {}

				template<typename... Args>
					auto using_(Args... args)
					-> _new_statement_t<using_t<void, Args...>>
					{
						return { *static_cast<typename Policies::_statement_t*>(this), using_data_t<void, Args...>{args...} };
					}

				template<typename... Args>
					auto dynamic_using(Args... args)
					-> _new_statement_t<using_t<_database_t, Args...>>
					{
						static_assert(not std::is_same<_database_t, void>::value, "dynamic_using must not be called in a static statement");
						return { *static_cast<typename Policies::_statement_t*>(this), using_data_t<_database_t, Args...>{args...} };
					}
			};
	};

	// Interpreters
	template<typename Context, typename Database, typename... Tables>
		struct serializer_t<Context, using_data_t<Database, Tables...>>
		{
			using T = using_data_t<Database, Tables...>;

			static Context& _(const T& t, Context& context)
			{
				if (sizeof...(Tables) == 0 and t._dynamic_tables.empty())
					return context;
				context << " USING ";
				interpret_tuple(t._tables, ',', context);
				if (sizeof...(Tables) and not t._dynamic_tables.empty())
					context << ',';
				interpret_list(t._dynamic_tables, ',', context);
				return context;
			}
		};
}

#endif