# Copyright (C) 2009, Tutorius.org # Copyright (C) 2009, Vincent Vinet # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program 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 General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA """ Core This module contains the core classes for tutorius """ import gtk import logging import copy import os from sugar.tutorius.dialog import TutoriusDialog from sugar.tutorius.gtkutils import find_widget from sugar.tutorius.services import ObjectStore logger = logging.getLogger("tutorius") class Tutorial (object): """ Tutorial Class, used to run through the FSM. """ def __init__(self, name, fsm,filename= None): """ Creates an unattached tutorial. """ object.__init__(self) self.name = name self.activity_init_state_filename = filename self.state_machine = fsm self.state_machine.set_tutorial(self) self.state = None self.handlers = [] self.activity = None #Rest of initialisation happens when attached def attach(self, activity): """ Attach to a running activity @param activity the activity to attach to """ #For now, absolutely detach if a previous one! if self.activity: self.detach() self.activity = activity ObjectStore().activity = activity ObjectStore().tutorial = self self._prepare_activity() self.state_machine.set_state("INIT") def detach(self): """ Detach from the current activity """ # Uninstall the whole FSM self.state_machine.teardown() #FIXME There should be some amount of resetting done here... self.activity = None def set_state(self, name): """ Switch to a new state """ logger.debug("==== NEW STATE: %s ====" % name) self.state_machine.set_state(name) # Currently unused -- equivalent function is in each state def _eventfilter_state_done(self, eventfilter): """ Callback handler for eventfilter to notify when we must go to the next state. """ #XXX Tests should be run here normally #Swith to the next state pointed by the eventfilter self.set_state(eventfilter.get_next_state()) def _prepare_activity(self): """ Prepare the activity for the tutorial by loading the saved state and emitting gtk signals """ #Load the saved activity if any if self.activity_init_state_filename is not None: #For now the file will be saved in the data folder #of the activity root directory filename = os.getenv("SUGAR_ACTIVITY_ROOT") + "/data/" +\ self.activity_init_state_filename if os.path.exists(filename): self.activity.read_file(filename) class State(object): """ This is a step in a tutorial. The state represents a collection of actions to undertake when entering the state, and a series of event filters with associated actions that point to a possible next state. """ def __init__(self, name, action_list=None, event_filter_list=None, tutorial=None): """ Initializes the content of the state, like loading the actions that are required and building the correct tests. @param action_list The list of actions to execute when entering this state @param event_filter_list A list of tuples of the form (event_filter, next_state_name), that explains the outgoing links for this state @param tutorial The higher level container of the state """ object.__init__(self) self.name = name self._actions = action_list or [] # Unused for now #self.tests = [] self._event_filters = event_filter_list or [] self.tutorial = tutorial def set_tutorial(self, tutorial): """ Associates this state with a tutorial. A tutorial must be set prior to executing anything in the state. The reason for this is that the states need to have access to the activity (via the tutorial) in order to properly register their callbacks on the activities' widgets. @param tutorial The tutorial that this state runs under. """ if self.tutorial == None : self.tutorial = tutorial else: raise RuntimeWarning(\ "The state %s was already associated with a tutorial." % self.name) def setup(self): """ Install the state itself, by first registering the event filters and then triggering the actions. """ for eventfilter in self._event_filters: eventfilter.install_handlers(self._event_filter_state_done_cb, activity=self.tutorial.activity) for action in self._actions: action.do() def teardown(self): """ Uninstall all the event filters that were active in this state. Also undo every action that was installed for this state. This means removing dialogs that were displayed, removing highlights, etc... """ # Remove the handlers for the all of the state's event filters for event_filter in self._event_filters: event_filter.remove_handlers() # Undo all the actions related to this state for action in self._actions: action.undo() def _event_filter_state_done_cb(self, event_filter): """ Callback for event filters. This function needs to inform the tutorial that the state is over and tell it what is the next state. @param event_filter The event filter that was called """ # Run the tests here, if need be # Warn the higher level that we wish to change state self.tutorial.set_state(event_filter.get_next_state()) # Model manipulation # These functions are used to simplify the creation of states def add_action(self, new_action): """ Adds an action to the state (only if it wasn't added before) @param new_action The new action to execute when in this state @return True if added, False otherwise """ if new_action not in self._actions: self._actions.append(new_action) return True return False # remove_action - We did not define names for the action, hence they're # pretty hard to remove on a precise basis def get_action_list(self): """ @return A list of actions that the state will execute """ return self._actions def clear_actions(self): """ Removes all the action associated with this state. A cleared state will not do anything when entered or exited. """ self._actions = [] def add_event_filter(self, event_filter): """ Adds an event filter that will cause a transition from this state. The same event filter may not be added twice. @param event_filter The new event filter that will trigger a transition @return True if added, False otherwise """ if event_filter not in self._event_filters: self._event_filters.append(event_filter) return True return False def get_event_filter_list(self): """ @return The list of event filters associated with this state. """ return self._event_filters def clear_event_filters(self): """ Removes all the event filters associated with this state. A state that was just cleared will become a sink and will be the end of the tutorial. """ self._event_filters = [] class FiniteStateMachine(State): """ This is a collection of states, with a start state and an end callback. It is used to simplify the development of the various tutorials by encapsulating a collection of states that represent a given learning process. For now, we will consider that there can only be states inserted in the FSM, and that there are no nested FSM inside. """ def __init__(self, name, tutorial=None, state_dict=None, start_state_name="INIT", action_list=None): """ The constructor for a FSM. Pass in the start state and the setup actions that need to be taken when the FSM itself start (which may be different from what is done in the first state of the machine). @param name A short descriptive name for this FSM @param tutorial The tutorial that will execute this FSM. If None is attached on creation, then one must absolutely be attached before executing the FSM with set_tutorial(). @param state_dict A dictionary containing the state names as keys and the state themselves as entries. @param start_state_name The name of the starting state, if different from "INIT" @param action_list The actions to undertake when initializing the FSM """ State.__init__(self, name) self.name = name self.tutorial = tutorial # Dictionnary of states contained in the FSM self._states = state_dict or {} self.start_state_name = start_state_name # If we have a filled input dictionary if len(self._states) > 0: self.current_state = self._states[self.start_state_name] else: self.current_state = None # Register the actions for the FSM - They will be processed at the # FSM level, meaning that when the FSM will start, it will first # execute those actions. When the FSM closes, it will tear down the # inner actions of the state, then close its own actions self.actions = action_list or [] # Flag to mention that the FSM was initialized self._fsm_setup_done = False # Flag that must be raised when the FSM is to be teared down self._fsm_teardown_done = False # Flag used to declare that the FSM has reached an end state self._fsm_has_finished = False def set_tutorial(self, tutorial): """ This associates the FSM to the given tutorial. It MUST be associated either in the constructor or with this function prior to executing the FSM. @param tutorial The tutorial that will execute this FSM. """ # If there was no tutorial associated if self.tutorial == None: # Associate it with this FSM and all the underlying states self.tutorial = tutorial for state in self._states.itervalues(): state.set_tutorial(tutorial) else: raise RuntimeWarning(\ "The FSM %s is already associated with a tutorial."%self.name) def setup(self): """ This function initializes the FSM the first time it is called. Then, every time it is called, it initializes the current state. """ # Are we associated with a tutorial? if self.tutorial == None: raise UnboundLocalError("No tutorial was associated with FSM %s" % self.name) # If we never initialized the FSM itself, then we need to run all the # actions associated with the FSM. if self._fsm_setup_done == False: # Remember the initial state - we might want to reset # or rewind the FSM at a later moment self.start_state = self._states[self.start_state_name] self.current_state = self.start_state # Flag the FSM level setup as done self._fsm_setup_done = True # Execute all the FSM level actions for action in self.actions: action.do() # Then, we need to run the setup of the current state self.current_state.setup() def set_state(self, new_state_name): """ This functions changes the current state of the finite state machine. @param new_state The identifier of the state we need to go to """ # TODO : Since we assume no nested FSMs, we don't set state on the # inner States / FSMs ## # Pass in the name to the internal state - it might be a FSM and ## # this name will apply to it ## self.current_state.set_state(new_state_name) # Make sure the given state is owned by the FSM if not self._states.has_key(new_state_name): # If we did not recognize the name, then we do not possess any # state by that name - we must ignore this state change request as # it will be done elsewhere in the hierarchy (or it's just bogus). return new_state = self._states[new_state_name] # Undo the actions of the old state self.teardown() # Insert the new state self.current_state = new_state # Call the initial actions in the new state self.setup() def get_current_state_name(self): """ Returns the name of the current state. @return A string representing the name of the current state """ return self.current_state.name def teardown(self): """ Revert any changes done by setup() """ # Teardown the current state if self.current_state is not None: self.current_state.teardown() # If we just finished the whole FSM, we need to also call the teardown # on the FSM level actions if self._fsm_has_finished == True: # Flag the FSM teardown as not needed anymore self._fsm_teardown_done = True # Undo all the FSM level actions here for action in self.actions: action.undo() # TODO : It might be nice to have a start() and stop() method for the # FSM. # Data manipulation section # These functions are dedicated to the building and editing of a graph. def add_state(self, new_state): """ Inserts a new state in the FSM. @param new_state The State object that will now be part of the FSM @raise KeyError In the case where a state with this name already exists """ if self._states.has_key(new_state.name): raise KeyError("There is already a state by this name in the FSM") self._states[new_state.name] = new_state # Not such a great name for the state accessor... We already have a # set_state name, so get_state would conflict with the notion of current # state - I would recommend having a set_current_state instead. def get_state_by_name(self, state_name): """ Fetches a state from the FSM, based on its name. If there is no such state, the method will throw a KeyError. @param state_name The name of the desired state @return The State object having the given name """ return self._states[state_name] def remove_state(self, state_name): """ Removes a state from the FSM. Raises a KeyError when the state is not existent. Warning : removing a state will also remove all the event filters that point to this given name, to preserve the FSM's integrity. If you only want to edit a state, you would be better off fetching this state with get_state_by_name(). @param state_name A string being the name of the state to remove @raise KeyError When the state_name does not a represent a real state stored in the dictionary """ state_to_remove = self._states[state_name] # Remove the state from the states' dictionnary for st in self._states.itervalues(): # Iterate through the list of event filters and remove those # that point to the state that will be removed #TODO : Move this code inside the State itself - we're breaking # encap :P for event_filter in st._event_filters: if event_filter.get_next_state() == state_name: st._event_filters.remove(event_filter) # Remove the state from the dictionary del self._states[state_name] # Exploration methods - used to know more about a given state def get_following_states(self, state_name): """ Returns a tuple of the names of the states that point to the given state. If there is no such state, the function raises a KeyError. @param state_name The name of the state to analyse @raise KeyError When there is no state by this name in the FSM """ state = self._states[state_name] next_states = set() for event_filter in state._event_filters: next_states.add(event_filter.get_next_state()) return tuple(next_states) def get_previous_states(self, state_name): """ Returns a tuple of the names of the state that can transition to the given state. If there is no such state, the function raises a KeyError. @param state_name The name of the state that the returned states might transition to. """ # This might seem a bit funny, but we don't verify if the given # state is present or not in the dictionary. # This is due to the fact that when building a graph, we might have a # prototypal state that has not been inserted yet. We could not know # which states are pointing to it until we insert it in the graph. states = [] # Walk through the list of states for st in self._states.itervalues(): for event_filter in st._event_filters: if event_filter.get_next_state() == state_name: states.append(event_filter.get_next_state()) continue return tuple(states) # Convenience methods to see the content of a FSM def __str__(self): out_string = "" for st in self._states.itervalues(): out_string += st.name + ", " return out_string