1 files changed, 52 insertions, 0 deletions
diff --git a/sleekxmpp/xmlstream/statemachine.py b/sleekxmpp/xmlstream/statemachine.py
new file mode 100644
index 00000000..66aa358f
--- /dev/null
+++ b/sleekxmpp/xmlstream/statemachine.py
@@ -0,0 +1,52 @@
+from __future__ import with_statement
+import threading
+
+class StateMachine(object):
+
+	def __init__(self, states=[], groups=[]):
+		self.lock = threading.Lock()
+		self.__state = {}
+		self.__default_state = {}
+		self.__group = {}
+		self.addStates(states)
+		self.addGroups(groups)
+	
+	def addStates(self, states):
+		with self.lock:
+			for state in states:
+				if state in self.__state or state in self.__group:
+					raise IndexError("The state or group '%s' is already in the StateMachine." % state)
+				self.__state[state] = states[state]
+				self.__default_state[state] = states[state]
+	
+	def addGroups(self, groups):
+		with self.lock:
+			for gstate in groups:
+				if gstate in self.__state or gstate in self.__group:
+					raise IndexError("The key or group '%s' is already in the StateMachine." % gstate)
+				for state in groups[gstate]:
+					if self.__state.has_key(state):
+						raise IndexError("The group %s contains a key %s which is not set in the StateMachine." % (gstate, state))
+				self.__group[gstate] = groups[gstate]
+	
+	def set(self, state, status):
+		with self.lock:
+			if state in self.__state:
+				self.__state[state] = bool(status)
+			else:
+				raise KeyError("StateMachine does not contain state %s." % state)
+	
+	def __getitem__(self, key):
+		if key in self.__group:
+			for state in self.__group[key]:
+				if not self.__state[state]:
+					return False
+			return True
+		return self.__state[key]
+	
+	def __getattr__(self, attr):
+		return self.__getitem__(attr)
+	
+	def reset(self):
+		self.__state = self.__default_state
+