PacketImpl.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 PacketImpl internal header */

#ifndef IH_SENF_senf_Packets_PacketImpl_
#define IH_SENF_senf_Packets_PacketImpl_ 1

// Custom includes
#include <map>
#include <string>
#include <ext/functional>
#include <boost/iterator/transform_iterator.hpp>
#include <boost/type_traits/is_convertible.hpp>
#include <boost/mpl/sizeof.hpp>
#include <boost/mpl/int.hpp>
#include <boost/mpl/or.hpp>
#include <boost/mpl/greater.hpp>
#include <boost/ptr_container/ptr_map.hpp>
#include <senf/Utils/TypeInfo.hh>
#include <senf/Utils/singleton.hh>
#include <senf/config.hh>
#include <senf/Utils/IgnoreValue.hh>

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

namespace senf {

    struct ComplexAnnotation;

namespace detail {

    template <class Annotation>
    struct IsComplexAnnotation
        : public boost::mpl::or_< boost::is_convertible<Annotation*, ComplexAnnotation*>,
                                  boost::mpl::greater<
                                      boost::mpl::sizeof_<Annotation>,
                                      boost::mpl::int_<SENF_PACKET_ANNOTATION_SLOTSIZE> > >
    {};

    class AnnotationRegistry
        : public senf::singleton<AnnotationRegistry>
    {
    public:
        typedef int key_type;

    private:
        struct RegistrationBase
        {
            virtual ~RegistrationBase () {};
            key_type key;
            virtual void v_dump(std::ostream & os, void * annotation) const = 0;
            virtual std::string v_name() const = 0;
            virtual bool v_isComplex() const = 0;
            virtual unsigned v_size() const = 0;
        };

        template <class Annotation>
        struct Registration
            : public RegistrationBase
        {
            void v_dump(std::ostream & os, void * annotation) const
                { os << * static_cast<Annotation*>(annotation); }
            std::string v_name() const
                { return prettyName(typeid(Annotation)); }
            bool v_isComplex() const
                { return boost::is_convertible<Annotation*, ComplexAnnotation*>::value; }
            unsigned v_size() const
                { return sizeof(Annotation); }
        };

        typedef boost::ptr_map<key_type, RegistrationBase> Registry;
        // Index must be a multi-map since two identically named classes
        // both in the anonymous namespace both have the same demangled name.
        // we could sort on the mangled name instead ...
        typedef std::multimap<std::string, key_type> Index;

    public:
        typedef boost::transform_iterator< ::__gnu_cxx::select2nd<Index::value_type>,
                                           Index::const_iterator > iterator;

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

        template <class Annotation> class RegistrationProxy;

        class EntryBase;
        template <class Annotation> class Entry;

        template <class Annotation>
        key_type registerAnnotation();

        void dump(key_type key, std::ostream & os, void * annotation) const;
        std::string name(key_type key) const;
        bool isComplex(key_type key) const;
        unsigned size(key_type key) const;

        template <class Annotation>
        static key_type lookup();

        iterator begin() const;
        iterator end() const;

        void dumpRegistrations(std::ostream & os) const;

    private:
        AnnotationRegistry();

        key_type simpleAnnotationCount_;
#ifndef SENF_PACKET_NO_COMPLEX_ANNOTATIONS
        key_type complexAnnotationCount_;
#endif

        Registry registry_;
        // The index is needed to ensure a persistent and reproducible
        // ordering of the annotations when dumping
        Index index_;

        friend class senf::singleton<AnnotationRegistry>;
    };

    template <class Annotation>
    class AnnotationRegistry::RegistrationProxy
    {
    public:
        RegistrationProxy()
            {
                AnnotationRegistry::Entry<Annotation>::key_ =
                    AnnotationRegistry::instance().registerAnnotation<Annotation>();
            }
    };

    class AnnotationRegistry::EntryBase
    {
    public:
        virtual ~EntryBase() {}

        virtual void * get() = 0;

        typedef EntryBase * ptr;
        virtual ptr clone() const = 0;
    };

    inline AnnotationRegistry::EntryBase::ptr new_clone( AnnotationRegistry::EntryBase const & entry)
    {
        return entry.clone();
    }

    template <class Annotation>
    class AnnotationRegistry::Entry
        : public AnnotationRegistry::EntryBase
    {
        static RegistrationProxy<Annotation> proxy_;
        static AnnotationRegistry::key_type key_;
    public:
        // We use this member to force instantiation of proxy_ ...
        static AnnotationRegistry::key_type key()
            { senf::IGNORE(&proxy_); return key_; }

        virtual void * get() { return & annotation_; }
        virtual EntryBase::ptr clone() const { return new Entry<Annotation>( *this); }

    private:
        Annotation annotation_;

        friend class AnnotationRegistry::RegistrationProxy<Annotation>;
    };

}}

//-/////////////////////////////////////////////////////////////////////////////////////////////////
#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: