def __pollDevice(latch):
# wait for data from the device using the asynchronous API. See
# http://libusb.sourceforge.net/api-1.0/
pollobj = select.poll()
pollfds = LibUSB.get_pollfds()
LOGGER.debug("retreived poll file descriptors: %s" % pollfds)
for (fd, events) in pollfds:
pollobj.register(fd, events)
while True:
latch.open()
try:
timeoutInMillis = None
t0 = datetime.datetime.now()
nextTimeout = LibUSB.get_next_timeout()
if nextTimeout is not None:
(secs, usecs) = nextTimeout
timeoutInMillis = secs * 1000.0 + usecs * 0.001
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug("next timeout: %(timeoutInMillis)f" % locals())
pollresult = pollobj.poll(timeoutInMillis) # milliseconds
t1 = datetime.datetime.now()
dt = t1 - t0
elapsedTimeInMillis = dt.seconds * 1000.0 + dt.microseconds * 0.001
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug("poll result: %(pollresult)s, timeout: %(timeoutInMillis)s, elapsed: %(elapsedTimeInMillis)f" % locals())
if (len(pollresult) > 0) or (timeoutInMillis is None) or (elapsedTimeInMillis > timeoutInMillis):
LibUSB.handle_events_timeout()
except Exception,e:
exc_type, exc_value, exc_traceback = sys.exc_info()
# msg = traceback.format_exception_only(exc_type, exc_value);
msg = traceback.format_exception(exc_type, exc_value, exc_traceback);
LOGGER.error("\n".join(msg))
