Source code for cherrypy.lib.locking

import datetime

[docs]class NeverExpires(object):
[docs] def expired(self): return False
[docs]class Timer(object): """ A simple timer that will indicate when an expiration time has passed. """ def __init__(self, expiration): 'Create a timer that expires at `expiration` (UTC datetime)' self.expiration = expiration
[docs] @classmethod def after(cls, elapsed): """ Return a timer that will expire after `elapsed` passes. """ return cls(datetime.datetime.utcnow() + elapsed)
[docs] def expired(self): return datetime.datetime.utcnow() >= self.expiration
[docs]class LockTimeout(Exception): 'An exception when a lock could not be acquired before a timeout period'
[docs]class LockChecker(object): """ Keep track of the time and detect if a timeout has expired """ def __init__(self, session_id, timeout): self.session_id = session_id if timeout: self.timer = Timer.after(timeout) else: self.timer = NeverExpires()
[docs] def expired(self): if self.timer.expired(): raise LockTimeout( 'Timeout acquiring lock for %(session_id)s' % vars(self)) return False