Remove the now useless state machine

2 files changed, 0 insertions, 292 deletions

diff --git a/slixmpp/thirdparty/statemachine.py b/slixmpp/thirdparty/statemachine.py
deleted file mode 100644
index 868dab24..00000000
--- a/slixmpp/thirdparty/statemachine.py
+++ /dev/null
@@ -1,286 +0,0 @@
-"""
-    Slixmpp: The Slick XMPP Library
-    Copyright (C) 2010  Nathanael C. Fritz
-    This file is part of Slixmpp.
-
-    See the file LICENSE for copying permission.
-"""
-
-import threading
-import time
-import logging
-
-log = logging.getLogger(__name__)
-
-
-class StateMachine(object):
-
-    def __init__(self, states=None):
-        if not states: states = []
-        self.lock = threading.Condition()
-        self.__states = []
-        self.addStates(states)
-        self.__default_state = self.__states[0]
-        self.__current_state = self.__default_state
-
-    def addStates(self, states):
-        self.lock.acquire()
-        try:
-            for state in states:
-                if state in self.__states:
-                    raise IndexError("The state '%s' is already in the StateMachine." % state)
-                self.__states.append(state)
-        finally:
-            self.lock.release()
-
-
-    def transition(self, from_state, to_state, wait=0.0, func=None, args=[], kwargs={}):
-        '''
-        Transition from the given `from_state` to the given `to_state`.
-        This method will return `True` if the state machine is now in `to_state`.  It
-        will return `False` if a timeout occurred the transition did not occur.
-        If `wait` is 0 (the default,) this method returns immediately if the state machine
-        is not in `from_state`.
-
-        If you want the thread to block and transition once the state machine to enters
-        `from_state`, set `wait` to a non-negative value.  Note there is no 'block
-        indefinitely' flag since this leads to deadlock.  If you want to wait indefinitely,
-        choose a reasonable value for `wait` (e.g. 20 seconds) and do so in a while loop like so:
-
-        ::
-
-            while not thread_should_exit and not state_machine.transition('disconnected', 'connecting', wait=20 ):
-                    pass # timeout will occur every 20s unless transition occurs
-            if thread_should_exit: return
-            # perform actions here after successful transition
-
-        This allows the thread to be responsive by setting `thread_should_exit=True`.
-
-        The optional `func` argument allows the user to pass a callable operation which occurs
-        within the context of the state transition (e.g. while the state machine is locked.)
-        If `func` returns a True value, the transition will occur.  If `func` returns a non-
-        True value or if an exception is thrown, the transition will not occur.  Any thrown
-        exception is not caught by the state machine and is the caller's responsibility to handle.
-        If `func` completes normally, this method will return the value returned by `func.`  If
-        values for `args` and `kwargs` are provided, they are expanded and passed like so:
-        `func( *args, **kwargs )`.
-        '''
-
-        return self.transition_any((from_state,), to_state, wait=wait,
-                                    func=func, args=args, kwargs=kwargs)
-
-
-    def transition_any(self, from_states, to_state, wait=0.0, func=None, args=[], kwargs={}):
-        '''
-        Transition from any of the given `from_states` to the given `to_state`.
-        '''
-
-        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:
-                raise ValueError("StateMachine does not contain from_state %s." % state)
-        if not to_state in self.__states:
-            raise ValueError("StateMachine does not contain to_state %s." % to_state)
-
-        if self.__current_state == to_state:
-            return True
-
-        start = time.time()
-        while not self.lock.acquire(False):
-            time.sleep(.001)
-            if (start + wait - time.time()) <= 0.0:
-                log.debug("==== Could not acquire lock in %s sec: %s -> %s ", wait, self.__current_state, to_state)
-                return False
-
-        while not self.__current_state in from_states:
-            # detect timeout:
-            remainder = start + wait - time.time()
-            if remainder > 0:
-                self.lock.wait(remainder)
-            else:
-                log.debug("State was not ready")
-                self.lock.release()
-                return False
-
-        try: # lock is acquired; all other threads will return false or wait until notify/timeout
-            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
-                return_val = func(*args,**kwargs) if func is not None else True
-
-                # some 'false' value returned from func,
-                # indicating that transition should not occur:
-                if not return_val:
-                    return return_val
-
-                log.debug(' ==== TRANSITION %s -> %s', self.__current_state, to_state)
-                self._set_state(to_state)
-                return return_val  # some 'true' value returned by func or True if func was None
-            else:
-                log.error("StateMachine bug!!  The lock should ensure this doesn't happen!")
-                return False
-        finally:
-            self.lock.notify_all()
-            self.lock.release()
-
-
-    def transition_ctx(self, from_state, to_state, wait=0.0):
-        '''
-        Use the state machine as a context manager.  The transition occurs on /exit/ from
-        the `with` context, so long as no exception is thrown.  For example:
-
-        ::
-
-            with state_machine.transition_ctx('one','two', wait=5) as locked:
-                if locked:
-                    # the state machine is currently locked in state 'one', and will
-                    # transition to 'two' when the 'with' statement ends, so long as
-                    # no exception is thrown.
-                    print 'Currently locked in state one: %s' % state_machine['one']
-
-                else:
-                    # The 'wait' timed out, and no lock has been acquired
-                    print 'Timed out before entering state "one"'
-
-            print 'Since no exception was thrown, we are now in state "two": %s' % state_machine['two']
-
-
-        The other main difference between this method and `transition()` is that the
-        state machine is locked for the duration of the `with` statement.  Normally,
-        after a `transition()` occurs, the state machine is immediately unlocked and
-        available to another thread to call `transition()` again.
-        '''
-
-        if not from_state in self.__states:
-            raise ValueError("StateMachine does not contain from_state %s." % from_state)
-        if not to_state in self.__states:
-            raise ValueError("StateMachine does not contain to_state %s." % to_state)
-
-        return _StateCtx(self, from_state, to_state, wait)
-
-
-    def ensure(self, state, wait=0.0, block_on_transition=False):
-        '''
-        Ensure the state machine is currently in `state`, or wait until it enters `state`.
-        '''
-        return self.ensure_any((state,), wait=wait, block_on_transition=block_on_transition)
-
-
-    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.
-
-        Note that due to the nature of the function, you cannot guarantee that
-        the entirety of some operation completes while you remain in a given
-        state.  That would require acquiring and holding a lock, which
-        would mean no other threads could do the same.  (You'd essentially
-        be serializing all of the threads that are 'ensuring' their tasks
-        occurred in some state.
-        '''
-        if not (isinstance(states,tuple) or isinstance(states,list)):
-            raise ValueError('states arg should be a tuple or list')
-
-        for state in states:
-            if not state in self.__states:
-                raise ValueError("StateMachine does not contain state '%s'" % state)
-
-        # 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.
-        self.lock.acquire()
-        start = time.time()
-        while not self.__current_state in states:
-            # detect timeout:
-            remainder = start + wait - time.time()
-            if remainder > 0:
-                self.lock.wait(remainder)
-            else:
-                self.lock.release()
-                return False
-        self.lock.release()
-        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.
-        Use `StateMachine.ensure(state)` to wait until the machine enters a certain state.
-        '''
-        return self.__current_state == state
-
-    def __str__(self):
-        return "".join(("StateMachine(", ','.join(self.__states), "): ", self.__current_state))
-
-
-
-class _StateCtx:
-
-    def __init__(self, state_machine, from_state, to_state, wait):
-        self.state_machine = state_machine
-        self.from_state = from_state
-        self.to_state = to_state
-        self.wait = wait
-        self._locked = False
-
-    def __enter__(self):
-        start = time.time()
-        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.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.lock.clear()
-        log.debug('StateMachine entered context in state: %s',
-                self.state_machine.current_state())
-        return True
-
-    def __exit__(self, exc_type, exc_val, exc_tb):
-        if exc_val is not None:
-            log.exception("StateMachine exception in context, remaining in state: %s\n%s:%s",
-                self.state_machine.current_state(), exc_type.__name__, exc_val)
-
-        if self._locked:
-            if exc_val is None:
-                log.debug(' ==== TRANSITION %s -> %s',
-                        self.state_machine.current_state(), self.to_state)
-                self.state_machine._set_state(self.to_state)
-
-            self.state_machine.lock.notify_all()
-            self.state_machine.lock.release()
-
-        return False # re-raise any exception
-
-if __name__ == '__main__':
-
-    def callback(s, s2):
-        print((1, s.transition('on', 'off', wait=0.0, func=callback, args=[s,s2])))
-        print((2, s2.transition('off', 'on', func=callback, args=[s,s2])))
-        return True
-
-    s = StateMachine(('off', 'on'))
-    s2 = StateMachine(('off', 'on'))
-    print((3, s.transition('off', 'on', wait=0.0, func=callback, args=[s,s2]),))
-    print((s.current_state(), s2.current_state()))
diff --git a/slixmpp/xmlstream/xmlstream.py b/slixmpp/xmlstream/xmlstream.py
index 8f7ecd7e..9c0acaa7 100644
--- a/slixmpp/xmlstream/xmlstream.py
+++ b/slixmpp/xmlstream/xmlstream.py
@@ -35,7 +35,6 @@ import xml.etree.ElementTree
 
 import slixmpp
 from slixmpp.util import Queue, QueueEmpty, safedict
-from slixmpp.thirdparty.statemachine import StateMachine
 from slixmpp.xmlstream import tostring, cert
 from slixmpp.xmlstream.stanzabase import StanzaBase, ET, ElementBase
 from slixmpp.xmlstream.handler import Waiter, XMLCallback
@@ -142,11 +141,6 @@ class XMLStream(object):
 
         self._der_cert = None
 
-        #: The connection state machine tracks if the stream is
-        #: ``'connected'`` or ``'disconnected'``.
-        self.state = StateMachine(('disconnected', 'connected'))
-        self.state._set_state('disconnected')
-
         #: The default port to return when querying DNS records.
         self.default_port = int(port)