Re: client_side and comm_close

On Mon, 2008-04-21 at 23:45 +1200, Amos Jeffries wrote:
> >> IMO, The proposed API _very_ first two lines of code in comm_close are to
> >> register a special Comm callback to perform the fclose() call, and then to
> >> immediately set fd_table flag closed for the rest of the comm_close
> >> process.
> >
> > Agreed on the flag, disagreed on the call. The special/internal Comm
> > call (to self) should be scheduled last (after all close callbacks) and
> > not first because the close handler might need access to some FD-related
> > info. That info should be preserved until all close handlers have been
> > called.
> >
> >> With that condition at the start we can guarantee that any registrations
> >> made during the close sequence are either non-FD-relevant or caught.
> >
> > Yes, the flag is sufficient for that. The internal "close for good" call
> > can still be last.
>
> I was thinking the close-for-good call would get caught as an fd
> operation on closed fd by the Async stuff if set after the flag.

Actually, the internal close-for-good call handler asserts that the flag
is set! This internal handler does not have the structure or the
restrictions of the public comm_* functions...

> >> The special Comm callback is only special in that it is not required to
> >> check flags open before fclose()'ing the system-level FD, which will allow
> >> new connections to open on the FD.
> >
> > It is special because it is calling an internal comm method not some
> > external close handler. Its profile and parameters are different. I
> > would not call it a callback because of that, but the label is not
> > important. It is not a close callback in terms of
> > comm_add_close_handler.
>
> Yet it seems to me it needs to be run as an async after the other async
> close-handlers are run. Due to the non-determinence of the async timing.

Yes, the it must called asynchronously. The call is scheduled after all
close callbacks are scheduled so that it will be dialed last.

Alex.
Received on Tue Apr 22 2008 - 13:03:54 MDT