Simple-Protocol-Lib/include/sp/protocol/MessageHandler.h

#pragma once

#include <tuple>

namespace sp
{
    // This class is inspired by https://arobenko.gitbooks.io/comms-protocols-cpp/content/

    // TAll is all the message types, that need to be handled, bundled in std::tuple
    template <typename TAll>
    class MessageHandler;

    // Big boy to process packets 20 by 20, preventing needlessly copying vtable many times at each inheritance stage
    template <typename T1,  typename T2,  typename T3, typename T4,  typename T5,
         typename T6,  typename T7,  typename T8, typename T9,  typename T10,
        typename T11, typename T12, typename T13, typename T14, typename T15,
        typename T16, typename T17, typename T18, typename T19, typename T20,
        typename... TRest>
    class MessageHandler<std::tuple<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T11, T13, T14, T15, T16, T17, T18, T19, T20, TRest...> > : public MessageHandler<std::tuple<TRest...> >
    {
        using Base = MessageHandler<std::tuple<TRest...> >;
    public:
        using Base::Handle; // Don't hide all Handle() functions from base classes
        virtual void Handle(const typename T1::DataType& msg)  {}
        virtual void Handle(const typename T2::DataType& msg)  {}
        virtual void Handle(const typename T3::DataType& msg)  {}
        virtual void Handle(const typename T4::DataType& msg)  {}
        virtual void Handle(const typename T5::DataType& msg)  {}
        virtual void Handle(const typename T6::DataType& msg)  {}
        virtual void Handle(const typename T7::DataType& msg)  {}
        virtual void Handle(const typename T8::DataType& msg)  {}
        virtual void Handle(const typename T9::DataType& msg)  {}
        virtual void Handle(const typename T10::DataType& msg) {}
        virtual void Handle(const typename T11::DataType& msg) {}
        virtual void Handle(const typename T12::DataType& msg) {}
        virtual void Handle(const typename T13::DataType& msg) {}
        virtual void Handle(const typename T14::DataType& msg) {}
        virtual void Handle(const typename T15::DataType& msg) {}
        virtual void Handle(const typename T16::DataType& msg) {}
        virtual void Handle(const typename T17::DataType& msg) {}
        virtual void Handle(const typename T18::DataType& msg) {}
        virtual void Handle(const typename T19::DataType& msg) {}
        virtual void Handle(const typename T20::DataType& msg) {}
    };

    // 10 by 10
    template <typename T1, typename T2, typename T3, typename T4, typename T5,
        typename T6, typename T7, typename T8, typename T9, typename T10,
        typename... TRest>
    class MessageHandler<std::tuple<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TRest...> > : public MessageHandler<std::tuple<TRest...> >
    {
        using Base = MessageHandler<std::tuple<TRest...> >;
    public:
        using Base::Handle; // Don't hide all Handle() functions from base classes
        virtual void Handle(const typename T1::DataType& msg)  {}
        virtual void Handle(const typename T2::DataType& msg)  {}
        virtual void Handle(const typename T3::DataType& msg)  {}
        virtual void Handle(const typename T4::DataType& msg)  {}
        virtual void Handle(const typename T5::DataType& msg)  {}
        virtual void Handle(const typename T6::DataType& msg)  {}
        virtual void Handle(const typename T7::DataType& msg)  {}
        virtual void Handle(const typename T8::DataType& msg)  {}
        virtual void Handle(const typename T9::DataType& msg)  {}
        virtual void Handle(const typename T10::DataType& msg) {}
    };

    // 5 by 5
    template <
        typename T1, typename T2, typename T3, typename T4, typename T5,
        typename... TRest>
    class MessageHandler<std::tuple<T1, T2, T3, T4, T5, TRest...> > : public MessageHandler<std::tuple<TRest...> >
    {
        using Base = MessageHandler<std::tuple<TRest...> >;
    public:
        using Base::Handle; // Don't hide all Handle() functions from base classes
        virtual void Handle(const typename T1::DataType& msg) {}
        virtual void Handle(const typename T2::DataType& msg) {}
        virtual void Handle(const typename T3::DataType& msg) {}
        virtual void Handle(const typename T4::DataType& msg) {}
        virtual void Handle(const typename T5::DataType& msg) {}
    };

    // Deal with rest with 4 types
    template <typename T1, typename T2, typename T3, typename T4>
    class MessageHandler<std::tuple<T1, T2, T3, T4> >
    {
    public:
        virtual ~MessageHandler() {}
        virtual void Handle(const typename T1::DataType& msg) {}
        virtual void Handle(const typename T2::DataType& msg) {}
        virtual void Handle(const typename T3::DataType& msg) {}
        virtual void Handle(const typename T4::DataType& msg) {}
    };

    // Deal with rest with 3 types
    template < typename T1, typename T2, typename T3>
    class MessageHandler<std::tuple<T1, T2, T3> >
    {
    public:
        virtual ~MessageHandler() {}
        virtual void Handle(const typename T1::DataType& msg) {}
        virtual void Handle(const typename T2::DataType& msg) {}
        virtual void Handle(const typename T3::DataType& msg) {}
    };

    // Deal with rest with 2 types
    template <typename T1, typename T2>
    class MessageHandler<std::tuple<T1, T2> >
    {
    public:
        virtual ~MessageHandler() {}
        virtual void Handle(const typename T1::DataType& msg) {}
        virtual void Handle(const typename T2::DataType& msg) {}
    };

    // Deal with rest with 1 type
    template <typename T1>
    class MessageHandler<std::tuple<T1> >
    {
    public:
        virtual ~MessageHandler() {}
        virtual void Handle(const typename T1::DataType& msg) {}
    };

    // Deal with rest with 0 type
    template <>
    class MessageHandler<std::tuple<> >
    {
    public:
        virtual ~MessageHandler() {}
    };

} // sp