Chris@16: /*
Chris@101:  *          Copyright Andrey Semashev 2007 - 2015.
Chris@16:  * Distributed under the Boost Software License, Version 1.0.
Chris@16:  *    (See accompanying file LICENSE_1_0.txt or copy at
Chris@16:  *          http://www.boost.org/LICENSE_1_0.txt)
Chris@16:  */
Chris@16: /*!
Chris@16:  * \file   sinks/frontend_requirements.hpp
Chris@16:  * \author Andrey Semashev
Chris@16:  * \date   22.04.2007
Chris@16:  *
Chris@16:  * The header contains definition of requirement tags that sink backend may declare
Chris@16:  * with regard to frontends. These requirements ensure that a backend will not
Chris@16:  * be used with an incompatible frontend.
Chris@16:  */
Chris@16: 
Chris@16: #ifndef BOOST_LOG_SINKS_FRONTEND_REQUIREMENTS_HPP_INCLUDED_
Chris@16: #define BOOST_LOG_SINKS_FRONTEND_REQUIREMENTS_HPP_INCLUDED_
Chris@16: 
Chris@16: #include <boost/mpl/aux_/na.hpp>
Chris@16: #include <boost/mpl/placeholders.hpp>
Chris@16: #include <boost/mpl/inherit.hpp>
Chris@16: #include <boost/mpl/inherit_linearly.hpp>
Chris@16: #include <boost/mpl/vector.hpp>
Chris@16: #include <boost/preprocessor/repetition/enum_params.hpp>
Chris@16: #include <boost/preprocessor/repetition/enum_params_with_a_default.hpp>
Chris@16: #include <boost/type_traits/is_base_of.hpp>
Chris@16: #include <boost/log/detail/config.hpp>
Chris@16: #include <boost/log/detail/header.hpp>
Chris@16: 
Chris@16: #ifdef BOOST_HAS_PRAGMA_ONCE
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #ifndef BOOST_LOG_COMBINE_REQUIREMENTS_LIMIT
Chris@16: //! The macro specifies the maximum number of requirements that can be combined with the \c combine_requirements metafunction
Chris@16: #define BOOST_LOG_COMBINE_REQUIREMENTS_LIMIT 5
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: BOOST_LOG_OPEN_NAMESPACE
Chris@16: 
Chris@16: namespace sinks {
Chris@16: 
Chris@16: /*!
Chris@16:  * The sink backend expects pre-synchronized calls, all needed synchronization is implemented
Chris@16:  * in the frontend (IOW, only one thread is feeding records to the backend concurrently, but
Chris@16:  * it is possible for several threads to write sequentially). Note that if a frontend supports
Chris@16:  * synchronized record feeding, it will also report capable of concurrent record feeding.
Chris@16:  */
Chris@16: struct synchronized_feeding {};
Chris@16: 
Chris@16: #if !defined(BOOST_LOG_NO_THREADS)
Chris@16: 
Chris@16: /*!
Chris@16:  * The sink backend ensures all needed synchronization, it is capable to handle multithreaded calls
Chris@16:  */
Chris@16: struct concurrent_feeding : synchronized_feeding {};
Chris@16: 
Chris@16: #else // !defined(BOOST_LOG_NO_THREADS)
Chris@16: 
Chris@16: //  If multithreading is disabled, threading models become redundant
Chris@16: typedef synchronized_feeding concurrent_feeding;
Chris@16: 
Chris@16: #endif // !defined(BOOST_LOG_NO_THREADS)
Chris@16: 
Chris@16: /*!
Chris@16:  * The sink backend requires the frontend to perform log record formatting before feeding
Chris@16:  */
Chris@16: struct formatted_records {};
Chris@16: 
Chris@16: /*!
Chris@16:  * The sink backend supports flushing
Chris@16:  */
Chris@16: struct flushing {};
Chris@16: 
Chris@16: #ifdef BOOST_LOG_DOXYGEN_PASS
Chris@16: 
Chris@16: /*!
Chris@16:  * The metafunction combines multiple requirement tags into one type. The resulting type will
Chris@16:  * satisfy all specified requirements (i.e. \c has_requirement metafunction will return positive result).
Chris@16:  */
Chris@16: template< typename... RequirementsT >
Chris@16: struct combine_requirements;
Chris@16: 
Chris@16: #else
Chris@16: 
Chris@16: template< BOOST_PP_ENUM_PARAMS_WITH_A_DEFAULT(BOOST_LOG_COMBINE_REQUIREMENTS_LIMIT, typename ReqT, mpl::na) >
Chris@16: struct combine_requirements :
Chris@16:     mpl::inherit_linearly<
Chris@16:         mpl::vector< BOOST_PP_ENUM_PARAMS(BOOST_LOG_COMBINE_REQUIREMENTS_LIMIT, ReqT) >,
Chris@16:         mpl::inherit2< mpl::_1, mpl::_2 >
Chris@16:     >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: #endif // BOOST_LOG_DOXYGEN_PASS
Chris@16: 
Chris@16: /*!
Chris@16:  * A helper metafunction to check if a requirement is satisfied. The \c TestedT template argument
Chris@16:  * should be the type combining one or several requirements and \c RequiredT is the requirement
Chris@16:  * to test against. The metafunction will yield a positive result if \c TestedT supports \c RequiredT.
Chris@16:  */
Chris@16: template< typename TestedT, typename RequiredT >
Chris@16: struct has_requirement :
Chris@16:     public is_base_of< RequiredT, TestedT >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: } // namespace sinks
Chris@16: 
Chris@16: BOOST_LOG_CLOSE_NAMESPACE // namespace log
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #include <boost/log/detail/footer.hpp>
Chris@16: 
Chris@16: #endif // BOOST_LOG_SINKS_FRONTEND_REQUIREMENTS_HPP_INCLUDED_