Parameters.ih

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//
// Copyright (c) 2020 Fraunhofer Institute for Applied Information Technology (FIT)
//                    Network Research Group (NET)
//                    Schloss Birlinghoven, 53754 Sankt Augustin, GERMANY
//                    Contact: support@wiback.org
//
// This file is part of the SENF code tree.
// It is licensed under the 3-clause BSD License (aka New BSD License).
// See LICENSE.txt in the top level directory for details or visit
// https://opensource.org/licenses/BSD-3-Clause
//


/** \file
    \brief Parameters internal header */

#ifndef IH_SENF_Utils_Logger_Parameters_
#define IH_SENF_Utils_Logger_Parameters_ 1

// Custom includes
#include <boost/preprocessor/seq/for_each_i.hpp>
#include <boost/preprocessor/facilities/apply.hpp>
#include <boost/preprocessor/punctuation/comma_if.hpp>
#include <boost/mpl/vector.hpp>
#include <boost/mpl/fold.hpp>
#include <boost/mpl/if.hpp>
#include <boost/utility/enable_if.hpp>
#include <boost/type_traits/is_convertible.hpp>
#include <senf/Utils/mpl.hh>
#include "Config.hh"
#include "Target.hh"

//-/////////////////////////////////////////////////////////////////////////////////////////////////

namespace senf {
namespace log {

    struct DefaultArea;
    struct Debug;
    struct NONE;

namespace detail {

    struct StreamBase;
    struct AreaBase;
    struct LevelBase;
    struct AliasBase;

    /// Internal: Parameter extractor
    template <class Base, class Param, unsigned N>
    struct Parameters_ {};

#ifndef DOXYGEN

    senf::mpl::rv<1> Parameters_select_(StreamBase *);
    template <class Base, class Param>
    struct Parameters_<Base,Param,1> : public Base
    { typedef Param stream; };

    senf::mpl::rv<2> Parameters_select_(AreaBase *);
    template <class Base, class Param>
    struct Parameters_<Base,Param,2> : public Base
    { typedef Param area; typedef Param area_base; };

    senf::mpl::rv<3> Parameters_select_(LevelBase *);
    template <class Base, class Param>
    struct Parameters_<Base,Param,3> : public Base
    { typedef Param level; };

    senf::mpl::rv<4> Parameters_select_(void *);
    template <class Base>
    struct Parameters_<Base,void,4> : public Base
    {};

    senf::mpl::rv<5> Parameters_select_(AliasBase *);
    template <class Base, class Param>
    struct Parameters_<Base,Param,5>
        : public Param::template apply<Base>::type
    {};

    // This trick makes any class with a SENFLogArea typedef member usable as area. A typedef of
    // this name is created by SENF_LOG_CLASS_AREA()
    template <class T>
    senf::mpl::rv<6> Parameters_select_(
        T *,
        typename boost::disable_if< boost::is_convertible<T*,StreamBase*> >::type * = 0,
        typename boost::disable_if< boost::is_convertible<T*,AreaBase*> >::type * = 0,
        typename boost::disable_if< boost::is_convertible<T*,LevelBase*> >::type * = 0,
        typename boost::disable_if< boost::is_convertible<T*,AliasBase*> >::type * = 0);
    template <class Base, class Param>
    struct Parameters_<Base,Param,6> : public Base
    { typedef typename Param::SENFLogArea area; typedef Param area_base; };

#endif

    /// Internal: Log message parameter collection
    template <class Base>
    struct Parameters : public Base
    {
        typedef typename boost::mpl::if_c< Base::level::value == NONE::value,
                                           typename Base::stream::defaultLevel,
                                           typename Base::level >::type level;

        static bool const compileEnabled = senf::log::Enabled<
            typename Base::stream,
            typename Base::area_base,
            level>::value;

        static bool enabled() {
            return compileEnabled
                && ( senf::log::detail::TargetRegistry::instance().fallbackRouting() ||
                     Base::area::instance().limit(Base::stream::instance()) <= level::value );
        }
    };

    /// Internal: Empty base class
    struct empty {};

    /// Internal: Merge log message parameter list
    struct Parameters_Merge
    {
        /// Internal: Embedded mpl template meta-function
        template <class Base, class Param>
        struct apply {
            typedef Parameters_<
                Base,
                Param,
                SENF_MPL_RV(Parameters_select_(static_cast<Param*>(0)))> type;
        };
    };

}}}

typedef senf::log::Debug       SENFLogDefaultStream;
typedef senf::log::DefaultArea SENFLogDefaultArea;
typedef senf::log::NONE        SENFLogDefaultLevel;

#define SENF_LOG_MERGE_ARG(r, data, i, elem) BOOST_PP_COMMA_IF(i) elem

#define SENF_LOG_MERGE_PARAMETERS_I(base, args)                                                   \
    boost::mpl::fold<                                                                             \
        boost::mpl::vector< BOOST_PP_SEQ_FOR_EACH_I(SENF_LOG_MERGE_ARG, _, args) >,               \
        base,                                                                                     \
        senf::log::detail::Parameters_Merge >::type

#define SENF_LOG_MERGE_PARAMETERS(args)                                                           \
    senf::log::detail::Parameters< SENF_LOG_MERGE_PARAMETERS_I(                                   \
        senf::log::detail::empty,                                                                 \
        (SENFLogDefaultStream)(SENFLogDefaultArea)(SENFLogDefaultLevel)args) >

#define SENF_LOG_MERGE_PARAMETERS_TPL(args)                                                       \
    senf::log::detail::Parameters< typename SENF_LOG_MERGE_PARAMETERS_I(                          \
        senf::log::detail::empty,                                                                 \
        (SENFLogDefaultStream)(SENFLogDefaultArea)(SENFLogDefaultLevel)args) >

//-/////////////////////////////////////////////////////////////////////////////////////////////////
#endif


// Local Variables:
// mode: c++
// fill-column: 100
// comment-column: 40
// c-file-style: "senf"
// indent-tabs-mode: nil
// ispell-local-dictionary: "american"
// compile-command: "scons -u test"
// End: