From 1bd7824f24a5ebaab4ce877b8434b9524d0336ad Mon Sep 17 00:00:00 2001 From: Lance Stout Date: Wed, 28 Mar 2012 23:58:38 -0700 Subject: Tidy up the state machine and use a threading condition instead of an event. Fixes issue #154 --- sleekxmpp/thirdparty/statemachine.py | 42 +++++++++++++++++++----------------- 1 file changed, 22 insertions(+), 20 deletions(-) (limited to 'sleekxmpp') diff --git a/sleekxmpp/thirdparty/statemachine.py b/sleekxmpp/thirdparty/statemachine.py index 8a7324b5..df3412d3 100644 --- a/sleekxmpp/thirdparty/statemachine.py +++ b/sleekxmpp/thirdparty/statemachine.py @@ -5,6 +5,7 @@ See the file LICENSE for copying permission. """ + import threading import time import logging @@ -15,8 +16,7 @@ log = logging.getLogger(__name__) class StateMachine(object): def __init__(self, states=[]): - self.lock = threading.Lock() - self.notifier = threading.Event() + self.lock = threading.Condition() self.__states = [] self.addStates(states) self.__default_state = self.__states[0] @@ -29,7 +29,8 @@ class StateMachine(object): if state in self.__states: raise IndexError("The state '%s' is already in the StateMachine." % state) self.__states.append(state) - finally: self.lock.release() + finally: + self.lock.release() def transition(self, from_state, to_state, wait=0.0, func=None, args=[], kwargs={}): @@ -73,8 +74,8 @@ class StateMachine(object): Transition from any of the given `from_states` to the given `to_state`. ''' - if not (isinstance(from_states,tuple) or isinstance(from_states,list)): - raise ValueError("from_states should be a list or tuple") + if not isinstance(from_states, (tuple, list, set)): + raise ValueError("from_states should be a list, tuple, or set") for state in from_states: if not state in self.__states: @@ -93,7 +94,7 @@ class StateMachine(object): # detect timeout: remainder = start + wait - time.time() if remainder > 0: - self.notifier.wait(remainder) + self.lock.wait(remainder) else: log.debug("State was not ready") self.lock.release() @@ -107,7 +108,8 @@ class StateMachine(object): # some 'false' value returned from func, # indicating that transition should not occur: - if not return_val: return return_val + if not return_val: + return return_val log.debug(' ==== TRANSITION %s -> %s', self.__current_state, to_state) self._set_state(to_state) @@ -116,8 +118,7 @@ class StateMachine(object): log.error("StateMachine bug!! The lock should ensure this doesn't happen!") return False finally: - self.notifier.set() # notify any waiting threads that the state has changed. - self.notifier.clear() + self.lock.notify_all() self.lock.release() @@ -191,36 +192,36 @@ class StateMachine(object): # will return immediately if no transition is in process. if block_on_transition: # we're not in the middle of a transition; don't hold the lock - if self.lock.acquire(False): self.lock.release() + if self.lock.acquire(False): + self.lock.release() # wait for the transition to complete - else: self.notifier.wait() + else: + self.lock.wait() start = time.time() while not self.__current_state in states: # detect timeout: remainder = start + wait - time.time() - if remainder > 0: self.notifier.wait(remainder) - else: return False + if remainder > 0: + self.lock.wait(remainder) + else: + return False return True - def reset(self): # TODO need to lock before calling this? self.transition(self.__current_state, self.__default_state) - def _set_state(self, state): #unsynchronized, only call internally after lock is acquired self.__current_state = state return state - def current_state(self): ''' Return the current state name. ''' return self.__current_state - def __getitem__(self, state): ''' Non-blocking, non-synchronized test to determine if we are in the given state. @@ -247,13 +248,14 @@ class _StateCtx: while not self.state_machine[self.from_state] or not self.state_machine.lock.acquire(False): # detect timeout: remainder = start + self.wait - time.time() - if remainder > 0: self.state_machine.notifier.wait(remainder) + if remainder > 0: + self.state_machine.lock.wait(remainder) else: log.debug('StateMachine timeout while waiting for state: %s', self.from_state) return False self._locked = True # lock has been acquired at this point - self.state_machine.notifier.clear() + self.state_machine.lock.clear() log.debug('StateMachine entered context in state: %s', self.state_machine.current_state()) return True @@ -269,7 +271,7 @@ class _StateCtx: self.state_machine.current_state(), self.to_state) self.state_machine._set_state(self.to_state) - self.state_machine.notifier.set() + self.state_machine.lock.notify_all() self.state_machine.lock.release() return False # re-raise any exception -- cgit v1.2.3