why use raft_server_t* in all functions? instead just use raft_server_t

[dimitar9]

Hi Willemt,
I like your work so much. I have a question here:

void raft_set_current_term(raft_server_t* me_, int term)
{
raft_server_private_t* me = (void*)me_;
me->current_term = term;
}

Like this,
why not just use raft_server_t, since it is already void*.
I don't quite understand. Could you please tell me?

Thank you

[willemt]

Hey that's a good question

The one and only reason why raft_server_t is void* is because of encapsulation.

A void* typedef means I can do whatever with my implementation and keep the details private.

There's no other reason for me using the void* typedef

Why do I use raft_server_t* instead of raft_server_t, which is a void* pointer already?
I don't like creating types that are pointers by default. It makes the code harder to understand. If you have pointer-less types then the person reading the code never needs to ask "is this type a pointer?". Seeing the explicit * makes the source more readable.

Why don't I use just void* in every function prototype?
The compiler does some handy type checking for you even if the typedef is a void_. For example, if someone passes a raft_peer_t_ into a function that expects a raft_server_t* it will complain. This is a win.

So if I'm effectively using void* * for all my raft_server_t* references why does it work?
This works because the void** is the same as void*. It's just a pointer. They're equivalent in this case.

Hope this makes sense.

In the last month I've found a better technique for encapsulation. If you're interested you might want to look at the heap_t typedef in https://github.com/willemt/heap/blob/master/heap.h