CODEWITHSUNDEEP
c++templatesstl
mvallebr
mvallebr

Reputation: 2508

How to generalize a class based on operator() arguments?

I have a class that is supposed to forward some arguments to a functor, but doing some additional stuff.

class SemaphoredEventRouterObserver {
   My_Semaphore m_semaphore;
   mywrapper_Function<void (*)(const Event &)> callback;
   SemaphoredEventRouterObserver(My_Semaphore semaphore, mywrapper_Function<void (*)(const Event &)> o_callback) : m_semaphore(semaphore) {
      callback = o_callback;
   }
   void operator()(const Event & event) {
      callback(event);
      semaphone.post();
   }
}

The problem is I might have to create dozens of classes like this, because for other functors the arguments vary, so instead of receiving const Event & event, I could receive string arg, int c, Myclass abc or anything else.

Is it possible to create a template class for this? I am using just stl and I cannot use boost, although I would be curious to see answers related to boost as well.

Upvotes: 0

Views: 66

Answers (1)

Jarod42
Jarod42

Reputation: 217293

With variadic template, you may do something like:

typename <typename... Ts>
class SemaphoredRouterObserver {
   My_Semaphore m_semaphore;
   mywrapper_Function<void (*)(Ts...)> callback;
public:
   SemaphoredEventRouterObserver(My_Semaphore semaphore,
                                 mywrapper_Function<void (*)(Ts...)> o_callback)
     : m_semaphore(semaphore),
       callback(o_callback)
   {}
   void operator()(Ts... args) {
      callback(args...);
      semaphone.post();
   }
};

And then 

using SemaphoredEventRouterObserver = SemaphoredRouterObserver<const Event&>;

Upvotes: 1

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