Simple-Protocol-Lib/include/sp/common/GenericHandler.h

#pragma once

#include <tuple>

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

    // TCommon is common interface class for all the messages
    // TAll is all the message types, that need to be handled, bundled in std::tuple
    template <typename TAll>
    class GenericHandler;

    // 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 GenericHandler<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 GenericHandler<std::tuple<TRest...> >
    {
        using Base = GenericHandler<std::tuple<TRest...> >;
    public:
        using Base::Handle; // Don't hide all Handle() functions from base classes
        virtual void Handle(const T1& msg)  {}
        virtual void Handle(const T2& msg)  {}
        virtual void Handle(const T3& msg)  {}
        virtual void Handle(const T4& msg)  {}
        virtual void Handle(const T5& msg)  {}
        virtual void Handle(const T6& msg)  {}
        virtual void Handle(const T7& msg)  {}
        virtual void Handle(const T8& msg)  {}
        virtual void Handle(const T9& msg)  {}
        virtual void Handle(const T10& msg) {}
        virtual void Handle(const T11& msg) {}
        virtual void Handle(const T12& msg) {}
        virtual void Handle(const T13& msg) {}
        virtual void Handle(const T14& msg) {}
        virtual void Handle(const T15& msg) {}
        virtual void Handle(const T16& msg) {}
        virtual void Handle(const T17& msg) {}
        virtual void Handle(const T18& msg) {}
        virtual void Handle(const T19& msg) {}
        virtual void Handle(const T20& 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 GenericHandler<std::tuple<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TRest...> > : public GenericHandler<std::tuple<TRest...> >
    {
        using Base = GenericHandler<std::tuple<TRest...> >;
    public:
        using Base::Handle; // Don't hide all Handle() functions from base classes
        virtual void Handle(const T1& msg)  {}
        virtual void Handle(const T2& msg)  {}
        virtual void Handle(const T3& msg)  {}
        virtual void Handle(const T4& msg)  {}
        virtual void Handle(const T5& msg)  {}
        virtual void Handle(const T6& msg)  {}
        virtual void Handle(const T7& msg)  {}
        virtual void Handle(const T8& msg)  {}
        virtual void Handle(const T9& msg)  {}
        virtual void Handle(const T10& msg) {}
    };

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

    // Deal with rest with 4 types
    template <typename T1, typename T2, typename T3, typename T4>
    class GenericHandler<std::tuple<T1, T2, T3, T4> >
    {
    public:
        virtual ~GenericHandler() {}
        virtual void Handle(const T1& msg) {}
        virtual void Handle(const T2& msg) {}
        virtual void Handle(const T3& msg) {}
        virtual void Handle(const T4& msg) {}
        // virtual void Handle(const TCommon&) {} //Nothing to do
    };

    // Deal with rest with 3 types
    template < typename T1, typename T2, typename T3>
    class GenericHandler<std::tuple<T1, T2, T3> >
    {
    public:
        virtual ~GenericHandler() {}
        virtual void Handle(const T1& msg) {}
        virtual void Handle(const T2& msg) {}
        virtual void Handle(const T3& msg) {}
        // virtual void Handle(const TCommon&) {} //Nothing to do
    };

    // Deal with rest with 2 types
    template <typename T1, typename T2>
    class GenericHandler<std::tuple<T1, T2> >
    {
    public:
        virtual ~GenericHandler() {}
        virtual void Handle(const T1& msg) {}
        virtual void Handle(const T2& msg) {}
        // virtual void Handle(const TCommon&) {} //Nothing to do
    };

    // Deal with rest with 1 type
    template <typename T1>
    class GenericHandler<std::tuple<T1> >
    {
    public:
        virtual ~GenericHandler() {}
        virtual void Handle(const T1& msg) {}
        // virtual void Handle(const TCommon&) {} //Nothing to do
    };

    // Deal with rest with 0 type
    template <>
    class GenericHandler<std::tuple<> >
    {
    public:
        virtual ~GenericHandler() {}
        // virtual void Handle(const TCommon&) {} //Nothing to do
    };

} // sp