Target.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 Target internal header */

#ifndef IH_SENF_Utils_Logger_Target_
#define IH_SENF_Utils_Logger_Target_ 1

// Custom includes
#include <set>
#include <boost/type_traits/is_same.hpp>
#include <boost/static_assert.hpp>
#include <boost/shared_ptr.hpp>
#include <senf/Utils/singleton.hh>
#include <senf/Utils/mpl.hh>
#include <senf/Utils/Console/LazyDirectory.hh>
#include <senf/Utils/Console/Parse.hh>

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

namespace senf {

    namespace console { class DirectoryNode; }

namespace log {
namespace detail {

    struct LogParameters {
        StreamBase const * stream;
        AreaBase const * area;
        unsigned level;
        void clear();
        void setDefaults();
        static LogParameters defaultParameters();
    };

    std::ostream & operator<<(std::ostream & os, LogParameters const & pm);

    void senf_console_parse_argument(console::ParseCommandInfo::TokensRange const & tokens,
                                     LogParameters & out);

    /** \brief Internal: Target registry */
    class TargetRegistry
        : public senf::singleton<TargetRegistry>
    {
    public:
        enum Level {
            VERBOSE = senf::log::VERBOSE::value,
            NOTICE = senf::log::NOTICE::value,
            MESSAGE = senf::log::MESSAGE::value,
            IMPORTANT = senf::log::IMPORTANT::value,
            CRITICAL = senf::log::CRITICAL::value,
            FATAL = senf::log::FATAL::value
        };

        using senf::singleton<TargetRegistry>::instance;

        void write(StreamBase const & stream, AreaBase const & area, unsigned level,
                   std::string const & msg);

        void routed();
        bool fallbackRouting();

        senf::console::ScopedDirectory<> & consoleDir();

        void dynamicTarget(std::unique_ptr<Target> target);

    private:
        TargetRegistry();
        ~TargetRegistry();

        void registerTarget(Target * target, std::string const & name);
        void unregisterTarget(Target * target);

        void consoleAreas(std::ostream & os);
        void consoleStreams(std::ostream & os);
        void consoleWrite(LogParameters parameters, std::string const & msg);
        void consoleRemoveTarget(Target * target);
        boost::shared_ptr<senf::console::DirectoryNode> consoleSelf(std::ostream & os);

        typedef std::set<Target *> Targets;
        Targets targets_;

        bool fallbackRouting_;

        console::LazyDirectory consoleDir_;

        Targets dynamicTargets_;

        friend class senf::log::Target;
        friend class senf::singleton<TargetRegistry>;
    };

    /** \brief Internal: Write log message */
    template <class Stream, class Area, class Level>
    void write(std::string const & msg);

#ifndef DOXYGEN

    // This code takes the routing target template arguments in any order and sorts them
    // by type (Stream, Area and Level).

    senf::mpl::rv<0u> RouteParameterCheck_(...);
    senf::mpl::rv<1u> RouteParameterCheck_(StreamBase *);
    senf::mpl::rv<2u> RouteParameterCheck_(AreaBase *);
    template <class T> senf::mpl::rv<3u> RouteParameterCheck_(T*, typename T::SENFLogArea * = 0);
    senf::mpl::rv<4u> RouteParameterCheck_(LevelBase *);

    // For g++ 4.0 (at least) we need to provide the fully scoped name for this default value.
    // no idea why. It works without the scope in 4.1
    template < class T, class A2, class A1,
               unsigned type = SENF_MPL_RV( senf::log::detail::RouteParameterCheck_(static_cast<T*>(0)) ) >
    struct RouteParameters
    {};

    template <class A2, class A1>
    struct RouteParameters<mpl::nil,A2,A1,0u>
        : public RouteParameters<A2,A1,mpl::nil>
    {};

    struct NilLevel {
        static unsigned const value = NONE::value;
    };

    template <>
    struct RouteParameters<mpl::nil,mpl::nil,mpl::nil,0u>
    {
        typedef mpl::nil Stream;
        typedef mpl::nil Area;
        typedef NilLevel Level;
    };

    template <class T, class A2, class A1>
    struct RouteParameters<T,A2,A1,1u>
        : public RouteParameters<A2,A1,mpl::nil>
    {
        typedef RouteParameters<A2,A1,mpl::nil> base;
        BOOST_STATIC_ASSERT(( boost::is_same<typename base::Stream, mpl::nil>::value ));
        typedef T Stream;
    };

    template <class T, class A2, class A1>
    struct RouteParameters<T,A2,A1,2u>
        : public RouteParameters<A2,A1,mpl::nil>
    {
        typedef RouteParameters<A2,A1,mpl::nil> base;
        BOOST_STATIC_ASSERT(( boost::is_same<typename base::Area, mpl::nil>::value ));
        typedef T Area;
    };

    template <class T, class A2, class A1>
    struct RouteParameters<T,A2,A1,3u>
        : public RouteParameters<A2,A1,mpl::nil>
    {
        typedef RouteParameters<A2,A1,mpl::nil> base;
        BOOST_STATIC_ASSERT(( boost::is_same<typename base::Area, mpl::nil>::value ));
        typedef typename T::SENFLogArea Area;
    };

    template <class T, class A2, class A1>
    struct RouteParameters<T,A2,A1,4u>
        : public RouteParameters<A2,A1,mpl::nil>
    {
        typedef RouteParameters<A2,A1,mpl::nil> base;
        BOOST_STATIC_ASSERT(( boost::is_same<typename base::Level, NilLevel>::value ));
        typedef T Level;
    };

    template <class T, class RV>
    struct InstanceP
    {
        static RV * value() { return & T::instance(); }
    };

    template <class RV>
    struct InstanceP<mpl::nil, RV>
    {
        static RV * value() { return 0; }
    };

#endif

}}}

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


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// c-file-style: "senf"
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// ispell-local-dictionary: "american"
// compile-command: "scons -u test"
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