[Python-Dev] release candidate rules and timeit API question (original) (raw)

Skip Montanaro skip@pobox.com
Mon, 30 Jun 2003 21:23:43 -0500 

Tim> It's not so fine that this delicate code is duplicated, so I'd
Tim> rather see an internal refactoring to use a common backoff-polling
Tim> class.

I recently copied it to my own code as well. I'd like to see it whacked into something reusable. This seems to work:

import time
class Timeout(Exception): pass

def await_condition(predicate, timeout):
    delay = 0.0005
    endtime = time.time() + timeout
    while True:
        if predicate():
            return
        remaining = endtime - time.time()
        if remaining <= 0:          # time's up, predicate always failed
            raise Timeout
        delay = min(delay * 2, remaining, .05)
        time.sleep(delay)           # reduce CPU usage by using a sleep

Skip