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Diffstat (limited to 'src/python/statemachine.py')
| -rw-r--r-- | src/python/statemachine.py | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/src/python/statemachine.py b/src/python/statemachine.py new file mode 100644 index 0000000..993ef9b --- /dev/null +++ b/src/python/statemachine.py @@ -0,0 +1,149 @@ +# 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.") |