[FFmpeg-devel] [RFC] Event loop

[Anton Khirnov]

Quoting Nicolas George (2021-01-02 12:28:30)
> Anton Khirnov (12021-01-01):
> > I do not think this is a good idea. There are enough event loops in the
> > world and making yet another one is not in scope for us. What we should
> > do instead is allow clean integration with existing event loops, mainly
> > by exporting the underlying file descriptors so they can be poll()ed on.
> 
> We must do that indeed, but that is not enough, you are missing part of
> the problem: FFmpeg has complex protocols that rely on several sockets,
> and that is 100% part of the scope. Currently, these protocols are
> implemented with an unsavory mix of polling and short timeouts. To fix
> them and make them properly usable, we need an event loop.

I don't see how that conclusion follows. If a protocol has multiple FDs,
we design the API to allow exporting multiple FDs. Why would we
absolutely need our own event loop?

> 
> So, we have only two choices (I consider "leaving everything in the mess
> it is" is not a choice): implement our own event loop or choose one as a
> mandatory requirement. AFAIK, adding new mandatory requirements is not
> the preferred policy.

It seems massively preferable to leave the choice of an event loop (if
any - polling is still a viable alternative for many simple cases) to
the user.

-- 
Anton Khirnov