Accessing a shared generator from multiple threads.

[Andrae Muys]

[Subject line changed to allow thread to be found more easily in
google-groups]

Alan Kennedy <alanmk at hotmail.com> wrote in message news:<400AB936.BA1D9D73 at hotmail.com>...
> [Alan Kennedy]
> >> I believe that the following definition of serialise will correct the
> >> problem (IFF I've understood the problem correctly :-)
> >>

It does look like the following version will work, I was too focused
on synchronising the underlying generator, and forgot that my code
also needed to be re-entrant.  Thanks for catching my mistake.

> >> #-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> >> import time
> >> import thread
> >> import threading
> >>
> >> class serialise:
> >>   "Wrap a generator in an iterator for thread-safe access"
> >>
> >>   def __init__(self, gen):
> >>     self.lock = threading.Lock()
> >>     self.gen = gen
> >>
> >>   def __iter__(self):
> >>     return self
> >>
> >>   def next(self):
> >>     self.lock.acquire()
> >>     try:
> >>       return self.gen.next()
> >>     finally:
> >>       self.lock.release()
> 
> [Ype Kingma]
> > Looks like a candidate for inclusion in a standard library to me.
> 
> Well, maybe :-)
> 
> To be honest, I don't have the time to write test cases, docs and
> patches. So I think I'll just leave it for people to find in the
> Google Groups archives ...
> 

Andrae Muys