Timeout class - initialize with a duration, evaluates as boolean True until timeout has expired.

timeout.py

# Python
import time

__all__ = ['Timeout']


class Timeout(object):

    def __init__(self, duration=None):
        # If initializing from another instance, create a new timeout from the
        # remaining time on the other.
        if isinstance(duration, Timeout):
            duration = duration.remaining
        self.reset(duration)

    def __repr__(self):
        if self._duration is None:
            return 'Timeout(None)'
        else:
            return 'Timeout(%f)' % self._duration

    def __hash__(self):
        return self._duration

    def __nonzero__(self):
        return self.block

    def _get_current_time(self):
        return time.time()

    def reset(self, duration=False):
        if duration is not False:
            self._duration = float(max(0, duration)) if duration is not None else None
        self._begin = self._get_current_time()

    def expire(self):
        self._begin = self._get_current_time() - max(0, self._duration or 0.0)

    @property
    def duration(self):
        return self._duration

    @property
    def elapsed(self):
        return float(max(0, self._get_current_time() - self._begin))

    @property
    def remaining(self):
        if self._duration is None:
            return None
        else:
            return float(max(0, self._duration + self._begin - self._get_current_time()))

    @property
    def block(self):
        remaining = self.remaining
        return bool(remaining or remaining is None)