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# libavg - Media Playback Engine.
# Copyright (C) 2003-2014 Ulrich von Zadow
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
# Current versions can be found at www.libavg.de
#
from methodref import methodref
import subprocess
import os
class State(object):
def __init__(self, transitions, enterFunc, leaveFunc):
self.transitions = {}
for destState, transfunc in transitions.items():
ref = methodref(transfunc)
self.transitions[destState] = ref
self.enterFunc = methodref(enterFunc)
self.leaveFunc = methodref(leaveFunc)
class StateMachine(object):
def __init__(self, name, startState):
self.__states = {}
self.__name = name
self.__startState = startState
self.__curState = startState
self.__trace = False
self.__initDone = False
def addState(self, state, transitions, enterFunc=None, leaveFunc=None):
if self.__initDone:
raise RuntimeError(
"StateMachine: Can't add new states after calling changeState")
if self.__states.has_key(state):
raise RuntimeError("StateMachine: Duplicate state " + state + ".")
if isinstance(transitions, (list, tuple)):
transitions = dict.fromkeys(transitions)
self.__states[state] = State(transitions, enterFunc, leaveFunc)
def changeState(self, newState):
if not(self.__initDone):
self.__initDone = True
self.__doSanityCheck()
if self.__trace:
print self.__name, ":", self.__curState, "-->", newState
if not(newState in self.__states):
raise RuntimeError('StateMachine: Attempt to change to nonexistent state '+
newState+'.')
assert(self.__curState in self.__states)
state = self.__states[self.__curState]
if newState in state.transitions:
if state.leaveFunc() != None:
state.leaveFunc()()
transitionFunc = state.transitions[newState]()
if transitionFunc != None:
try:
transitionFunc(self.__curState, newState)
except TypeError:
transitionFunc()
self.__curState = newState
enterFunc = self.__states[self.__curState].enterFunc()
if enterFunc != None:
enterFunc()
else:
raise RuntimeError('StateMachine: State change from '+self.__curState+' to '+
newState+' not allowed.')
def traceChanges(self, trace):
self.__trace = trace
@property
def state(self):
return self.__curState
def dump(self):
for oldStateName, state in self.__states.iteritems():
print oldStateName, ("(enter: " + self.__getNiceFuncName(state.enterFunc)
+ ", leave: " + self.__getNiceFuncName(state.leaveFunc) + "):")
for newState, func in state.transitions.iteritems():
print " -->", newState, ":", self.__getNiceFuncName(func)
print "Current state:", self.__curState
def makeDiagram(self, fName, showMethods=False):
def writeState(stateName, state):
label = stateName
if showMethods:
if state.enterFunc.__name__ is not(None):
label += ('<br/><font point-size="10">entry/'
+ state.enterFunc.__name__ + '</font>')
if state.leaveFunc.__name__ is not(None):
label += ('<br/><font point-size="10">exit/'
+ state.leaveFunc.__name__ + '</font>')
dotFile.write(' "'+stateName+'" [label=<'+label+'>];\n')
def writeTransition(origState, destState, func):
dotFile.write(' "'+origState+'" -> "'+destState+'"')
if showMethods and func and func.__name__ is not(None):
dotFile.write(' [label="/'+func.__name__+'", fontsize=10]')
dotFile.write(";\n")
dotFile = open("tmp.dot", "w")
dotFile.write('digraph "'+self.__name+'" {\n')
dotFile.write(' node [fontsize=12, shape=box, style=rounded];\n')
dotFile.write(' startstate [shape=point, height=0.2, width=0.2, label=""];\n')
dotFile.write(' { rank=source; "startstate" };\n')
writeTransition("startstate", self.__startState, None)
for stateName, state in self.__states.iteritems():
writeState(stateName, state)
for destState, func in state.transitions.iteritems():
writeTransition(stateName, destState, func)
dotFile.write(' "'+self.__curState+'" [style="rounded,bold"];\n')
dotFile.write('}\n')
dotFile.close()
try:
subprocess.call(["dot", "tmp.dot", "-Tpng", "-o"+fName])
except OSError:
raise RuntimeError("dot executable not found. graphviz needs to be installed for StateMachine.makeDiagram to work.")
os.remove("tmp.dot")
def __getNiceFuncName(self, f):
if f.__name__ is not(None):
return f.__name__
else:
return "None"
def __doSanityCheck(self):
for stateName, state in self.__states.iteritems():
for transitionName in state.transitions.iterkeys():
if not(self.__states.has_key(transitionName)):
raise RuntimeError("StateMachine: transition " + stateName + " -> " +
transitionName + " has an unknown destination state.")
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