diff options
| -rw-r--r-- | sleekxmpp/xmlstream/statemachine.py | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/sleekxmpp/xmlstream/statemachine.py b/sleekxmpp/xmlstream/statemachine.py index dc54bb88..fab38dc3 100644 --- a/sleekxmpp/xmlstream/statemachine.py +++ b/sleekxmpp/xmlstream/statemachine.py @@ -91,7 +91,6 @@ class StateMachine(object): else: return False try: # lock is acquired; all other threads will return false or wait until notify/timeout - self.notifier.clear() if self.__current_state in from_states: # should always be True due to lock # Note that func might throw an exception, but that's OK, it aborts the transition @@ -108,7 +107,8 @@ class StateMachine(object): log.error( "StateMachine bug!! The lock should ensure this doesn't happen!" ) return False finally: - self.notifier.set() + self.notifier.set() # notify any waiting threads that the state has changed. + self.notifier.clear() self.lock.release() @@ -154,7 +154,7 @@ class StateMachine(object): return self.ensure_any( (state,), wait=wait ) - def ensure_any(self, states, wait=0.0): + def ensure_any(self, states, wait=0.0, block_on_transition=False): ''' Ensure we are currently in one of the given `states` or wait until we enter one of those states. @@ -173,11 +173,15 @@ class StateMachine(object): if not state in self.__states: raise ValueError( "StateMachine does not contain state '%s'" % state ) - # Locking never really gained us anything here, since the lock was released - # before the function returned anyways. The only thing it _did_ do was - # increase the probability that this function would block for longer than - # intended if a `transition` function or context was running while holding - # the lock. + # if we're in the middle of a transition, determine whether we should + # 'fall back' to the 'current' state, or wait for the new state, in order to + # avoid an operation occurring in the wrong state. + # TODO another option would be an ensure_ctx that uses a semaphore to allow + # threads to indicate they want to remain in a particular state. + + # will return immediately if no transition is in process. + if block_on_transition: self.notifier.wait() + start = time.time() while not self.__current_state in states: # detect timeout: |