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