[Twisted-Python] callFromThread with return

[Andrew Bennetts]

On Mon, Oct 06, 2003 at 10:30:06PM -0400, Itamar Shtull-Trauring wrote:
> 
> t.i,threads should indeed have a utility function that does this for
> you. It would need to turn Failures into exceptions and deal
> transparently with Deferreds, of course.

I posted something like this to this thread earlier:

-----
import threading, sys
from twisted.internet import reactor

def blockingCallFromThread(func):
    e = threading.Event()
    l = []
    def wrapped_func():
        try:
            l.append(func)
        except:
            l.append(sys.exc_info())
            l.append(0)
        else:
            l.append(1)
        e.set()
    reactor.callFromThread(wrapped_func)
    e.wait()
    result, ok = l
    if ok:
        return result
    else:
        # Whee!  Cross-thread exceptions!
        raise result[0], result[1], result[2]
----

It doesn't deal with Failures or Deferreds, but it does everything else.
Oh, and it's not tested.  If I had already written test cases, I probably
would've checked it in by now ;)

(And I'm sure there's a better name for it than 'blockingCallFromThread'...)

-Andrew.