sqlpp11/include/sqlpp11/custom_query.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_CUSTOM_QUERY_H
#define SQLPP_CUSTOM_QUERY_H

#include <sqlpp11/connection.h>
#include <sqlpp11/interpret_tuple.h>
#include <sqlpp11/hidden.h>
#include <sqlpp11/detail/get_first.h>

namespace sqlpp
{
	template<typename Database, typename... Parts>
	struct custom_query_t;

	namespace detail
	{
		template<typename Db, typename... Parts>
		struct custom_parts_t
		{
			using _custom_query_t = custom_query_t<Db, Parts...>;
			using _result_type_provider = detail::get_first_if<is_return_value_t, noop, Parts...>;
			using _result_methods_t = typename _result_type_provider::template _result_methods_t<_result_type_provider>;
		};
	}

	template<typename Database, typename... Parts>
	struct custom_query_t:
		private detail::custom_parts_t<Database, Parts...>::_result_methods_t
	{
		using _methods_t = typename detail::custom_parts_t<Database, Parts...>::_result_methods_t;
		using _traits = make_traits<no_value_t>;
		using _recursive_traits = make_recursive_traits<Parts...>;

		using _parameter_check = typename std::conditional<std::tuple_size<typename _recursive_traits::_parameters>::value == 0,
					consistent_t, assert_no_parameters_t>::type;
		using _run_check = detail::get_first_if<is_inconsistent_t, consistent_t, 
					_parameter_check>;
		using _prepare_check = consistent_t;

		custom_query_t(Parts... parts):
			_parts(parts...)
		{}

		custom_query_t(std::tuple<Parts...> parts):
			_parts(parts)
		{}

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

		template<typename Db>
		auto _run(Db& db) const	-> decltype(std::declval<_methods_t>()._run(db, *this))
		{
			_run_check::_();
			return _methods_t::_run(db, *this);
		}

		template<typename Db>
		auto _prepare(Db& db) const	-> decltype(std::declval<_methods_t>()._prepare(db, *this))
		{
			_prepare_check::_();
			return _methods_t::_prepare(db, *this);
		}

		static constexpr size_t _get_static_no_of_parameters()
		{
			return std::tuple_size<parameters_of<custom_query_t>>::value;
		}

		size_t _get_no_of_parameters() const
		{
			return _get_static_no_of_parameters();
		}

		template<typename Part>
			auto with_result_type_of(Part part)
			-> custom_query_t<Database, Part, Parts...>
			{
				return {tuple_cat(std::make_tuple(part), _parts)};
			}

		std::tuple<Parts...> _parts;
	};

	template<typename Context, typename Database, typename... Parts>
		struct serializer_t<Context, custom_query_t<Database, Parts...>>
		{
			using T = custom_query_t<Database, Parts...>;

			static Context& _(const T& t, Context& context)
			{
				interpret_tuple_without_braces(t._parts, " ", context);
				return context;
			}
		};

	template<typename... Parts>
		auto custom_query(Parts... parts)
		-> custom_query_t<void, wrap_operand_t<Parts>...>
		{
			static_assert(sizeof...(Parts) > 0, "custom query requires at least one argument");
			return custom_query_t<void, wrap_operand_t<Parts>...>(parts...);
		}

	template<typename Database, typename... Parts>
		auto dynamic_custom_query(const Database&, Parts... parts)
		-> custom_query_t<Database, wrap_operand_t<Parts>...>
		{
			static_assert(sizeof...(Parts) > 0, "custom query requires at least one query argument");
			static_assert(std::is_base_of<connection, Database>::value, "Invalid database parameter");

			return custom_query_t<Database, wrap_operand_t<Parts>...>(parts...);
		}
}
#endif