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path: root/tutorius/TProbe.py
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# Copyright (C) 2009, Tutorius.org
#
# 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 1 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

import logging
LOGGER = logging.getLogger("sugar.tutorius.TProbe")
import os

import gobject

import dbus
import dbus.service
import cPickle as pickle


from . import addon
from .services import ObjectStore
from .properties import TPropContainer

from .dbustools import remote_call, save_args, ignore, logError
import copy

"""
  --------------------
  |  ProbeManager    |
  --------------------
           |
           V
  --------------------                ----------
  |    ProbeProxy    |<---- DBus ---->| TProbe |
  --------------------                ----------

"""
#TODO Add stub error handling for remote calls in the classes so that it will
# be clearer how errors can be handled in the future.


class TProbe(dbus.service.Object):
    """ Tutorius Probe
        Defines an entry point for Tutorius into activities that allows
        performing actions and registering events onto an activity via 
        a DBUS Interface.
    """

    def __init__(self, activity, service_proxy=None):
        """
        Create and register a TProbe for an activity.

        @param activity activity reference, must be a gtk container
        @param service_proxy A Service proxy object to do the registering 
        """
        # Moving the ObjectStore assignment here, in the meantime
        # the reference to the activity shouldn't be share as a
        # global variable but passed by the Probe to the objects 
        # that requires it
        self._activity = activity
        
        if service_proxy == None:
            from .service import ServiceProxy 

        self._service_proxy = service_proxy or ServiceProxy()

        ObjectStore().activity = activity

        self._activity_name = activity.get_bundle_id()
        self._unique_id = activity.get_id()

        LOGGER.debug("TProbe :: Creating TProbe for %s (%d)", self._activity_name, os.getpid())
        LOGGER.debug("TProbe :: Current gobject context: %s", str(gobject.main_context_default()))
        LOGGER.debug("TProbe :: Current gobject depth: %s", str(gobject.main_depth()))
        self._session_bus = dbus.SessionBus()

        # Giving a new name because _name is already used by dbus
        self._name2 = dbus.service.BusName(self._activity_name, self._session_bus)
        dbus.service.Object.__init__(self, self._session_bus, "/tutorius/Probe/"+str(self._unique_id))

        # Add the dictionary we will use to store which actions and events
        # are known
        self._installedActions = {}
        self._subscribedEvents = {}

        LOGGER.debug("TProbe :: registering '%s' with unique_id '%s'", self._activity_name, activity.get_id())
        self._service_proxy.register_probe(self._activity_name, self._unique_id)

    def start(self):
        """
        Optional method to call if the probe is not inserted into an
        existing activity. Starts a gobject mainloop
        """
        mainloop = gobject.MainLoop()
        mainloop.run()

    def stop(self):
        """
        Clean up the probe when finished.  Should be called just
        before a process ends
        """
        from .service import ServiceProxy
        LOGGER.debug("TProbe :: unregistering '%s' with unique_id '%s'", self._activity_name, self._unique_id)
        ServiceProxy().unregister_probe(self._unique_id)

    @dbus.service.method("org.tutorius.ProbeInterface",
                         in_signature='s', out_signature='')
    def registered(self, service):
        print ("Registered with: " + str(service))

    @dbus.service.method("org.tutorius.ProbeInterface",
                         in_signature='', out_signature='s')
    def ping(self):
        """ 
        Allows testing the connection to a Probe 
        @return string "alive"
        """
        return "alive"

    # ------------------ Action handling --------------------------------------
    @dbus.service.method("org.tutorius.ProbeInterface",
                         in_signature='s', out_signature='s')
    def install(self, pickled_action):
        """ 
        Install an action on the Activity
        @param pickled_action string pickled action
        @return string address of installed action
        """
        loaded_action = pickle.loads(str(pickled_action))
        action = addon.create(loaded_action.__class__.__name__)

        address = self._generate_action_reference(action)

        self._installedActions[address] = action

        if action._props:
            action._props.update(loaded_action._props)

        action.do(activity=self._activity)
        
        return address

    @dbus.service.method("org.tutorius.ProbeInterface",
                         in_signature='ss', out_signature='')
    def update(self, address, action_props):
        """
        Update an already registered action
        @param address string address returned by install()
        @param action_props pickled action properties
        @return None
        """
        action = self._installedActions[address]

        if action._props:
            props = pickle.loads(str(action_props))
            action._props.update(props)
            action.undo()
            action.do()

    @dbus.service.method("org.tutorius.ProbeInterface",
                         in_signature='s', out_signature='')
    def uninstall(self, address):
        """
        Uninstall an action
        @param address string address returned by install()
        @return None
        """
        if self._installedActions.has_key(address):
            action = self._installedActions[address]
            action.undo()
            self._installedActions.pop(address)
    

    # ------------------ Event handling ---------------------------------------
    @dbus.service.method("org.tutorius.ProbeInterface",
                         in_signature='s', out_signature='s')
    def subscribe(self, pickled_event):
        """ 
        Subscribe to an Event
        @param pickled_event string pickled EventFilter
        @return string unique name of registered event
        """
        #TODO Perform event unmapping once Tutorials use abstract events 
        #   instead of concrete EventFilters that are tied to their 
        #   implementation.
        eventfilter = pickle.loads(str(pickled_event))

        # The callback uses the event defined previously and each
        # successive call to subscribe will register a different
        # callback that references a different event
        def callback(*args):
            self.notify(eventfilter)

        eventfilter.install_handlers(callback, activity=self._activity)

        name = self._generate_event_reference(eventfilter)
        self._subscribedEvents[name] = eventfilter
        
        return name

    @dbus.service.method("org.tutorius.ProbeInterface",
                         in_signature='s', out_signature='')
    def unsubscribe(self, address):
        """
        Remove subscription to an event
        @param address string adress returned by subscribe()
        @return None
        """

        if self._subscribedEvents.has_key(address):
            eventfilter = self._subscribedEvents[address]
            eventfilter.remove_handlers()
            self._subscribedEvents.pop(address)

    @dbus.service.signal("org.tutorius.ProbeInterface")
    def eventOccured(self, event):
        # We need no processing now, the signal will be sent
        # when the method exit
        pass

    # The actual method we will call on the probe to send events
    def notify(self, event):
        LOGGER.debug("TProbe :: notify event %s", str(event))
        #Check that this event is even allowed
        if event in self._subscribedEvents.values():
            self.eventOccured(pickle.dumps(event))
        else:
            raise RuntimeWarning("Attempted to raise an unregistered event")

    # Return a unique name for this action 
    def _generate_action_reference(self, action):
        # TODO elavoie 2009-07-25 Should return a universal address
        name = action.__class__.__name__
        suffix = 1

        while self._installedActions.has_key(name+str(suffix)):
            suffix += 1

        return name + str(suffix)


    # Return a unique name for this event
    def _generate_event_reference(self, event):
        # TODO elavoie 2009-07-25 Should return a universal address
        name = event.__class__.__name__
        #Keep the counter to avoid looping all the time
        suffix = getattr(self, '_event_ref_suffix', 0 ) + 1

        while self._subscribedEvents.has_key(name+str(suffix)):
            suffix += 1
        
        #setattr(self, '_event_ref_suffix', suffix)

        return name + str(suffix)

class ProbeProxy:
    """
    ProbeProxy is a Proxy class for connecting to a remote TProbe.

    It provides an object interface to the TProbe, which requires pickled
    strings, across a DBus communication.
    """
    def __init__(self, activityName, unique_id):
        """
        Constructor
        @param activityName generic activity name. Must be a valid dbus bus name.
        @param unique_id unique id specific to an instance of an activity
        """
        LOGGER.debug("ProbeProxy :: Creating ProbeProxy for %s (%d)", activityName, os.getpid())
        LOGGER.debug("ProbeProxy :: Current gobject context: %s", str(gobject.main_context_default()))
        LOGGER.debug("ProbeProxy :: Current gobject depth: %s", str(gobject.main_depth()))
        bus = dbus.SessionBus()
        self._object = bus.get_object(activityName, "/tutorius/Probe/"+str(unique_id))
        self._probe = dbus.Interface(self._object, "org.tutorius.ProbeInterface")
        
        self._actions = {}
        # We keep those two data structures to be able to have multiple callbacks
        # for the same event and be able to remove them independently
        # _subscribedEvents holds a list of callback addresses's for each event
        # _registeredCallbacks holds the functions to call for each address
        self._subscribedEvents = {}
        self._registeredCallbacks = {}


        self._object.connect_to_signal("eventOccured", self._handle_signal, dbus_interface="org.tutorius.ProbeInterface")
    
    def _handle_signal(self, pickled_event):
        event = pickle.loads(str(pickled_event))
        LOGGER.debug("ProbeProxy :: Received Event : %s %s", str(event), str(event._props.items()))

        LOGGER.debug("ProbeProxy :: Currently %d events registered", len(self._registeredCallbacks))
        if self._registeredCallbacks.has_key(event):
            for callback in self._registeredCallbacks[event].values():
                callback(event)
        else:
            for event in self._registeredCallbacks.keys():
                LOGGER.debug("==== %s", str(event._props.items()))
            LOGGER.debug("ProbeProxy :: Event does not appear to be registered")

    def isAlive(self):
        try:
            return self._probe.ping() == "alive"
        except:
            return False

    def __update_action(self, action, callback, address):
        LOGGER.debug("ProbeProxy :: Updating action %s with address %s", str(action), str(address))
        self._actions[action] = str(address)
        callback(address)

    def __clear_action(self, action):
        self._actions.pop(action, None)

    def install(self, action, action_installed_cb, error_cb):
        """
        Install an action on the TProbe's activity
        @param action Action to install
        @param action_installed_cb The callback function to call once the action is installed
        @param error_cb The callback function to call when an error happens
        @return None
        """
        self._probe.install(pickle.dumps(action), 
                        reply_handler=save_args(self.__update_action, action, action_installed_cb),
                        error_handler=save_args(error_cb, action))

    def update(self, action_address, newaction):
        """
        Update an already installed action's properties and run it again
        @param action_address The address of the action to update. This is 
                            provided by the install callback method.
        @param newaction Action to update it with
        @param block Force a synchroneous dbus call if True
        @return None
        """
        #TODO review how to make this work well
        if not action_address in self._actions.values():
            raise RuntimeWarning("Action not installed")
        #TODO Check error handling
        return remote_call(self._probe.update, (action_address, pickle.dumps(newaction._props)), block=False)

    def uninstall(self, action_address):
        """
        Uninstall an installed action
        @param action_address The address of the action to uninstall. This address was given
                                on action installation
        @param block Force a synchroneous dbus call if True
        """
        for (this_action, this_address) in self._actions.items():
            if this_address == action_address: 
                remote_call(self._probe.uninstall,(action_address,))
                del self._actions[this_action]
                break

    def __update_event(self, event_name, event, callback, event_subscribed_cb, address):
        LOGGER.debug("ProbeProxy :: Registered event %s with address %s", str(hash(event)), str(address))
        # Since multiple callbacks could be associated to the same
        # event signature, we will store multiple callbacks
        # in a dictionary indexed by the unique address
        # given for this subscribtion and access this
        # dictionary from another one indexed by event
        address = str(address)

        # We use the event object as a key
        if not self._registeredCallbacks.has_key(event):
            self._registeredCallbacks[event] = {}

        # TODO elavoie 2009-07-25 decide on a proper exception
        # taxonomy
        if self._registeredCallbacks[event].has_key(address):
            # Oops, how come we have two similar addresses?
            # send the bad news!
            raise Exception("Probe subscribe exception, the following address already exists: " + str(address))

        self._registeredCallbacks[event][address] = callback

        # We will keep another dictionary to remember the
        # event that was associated to this unique address
        # Let's copy to make sure that even if the event
        # passed in is modified later it won't screw up
        # our dictionary (python pass arguments by reference)
        self._subscribedEvents[address] = copy.copy(event)

        event_subscribed_cb(address)
        return address

    def __clear_event(self, address):
        LOGGER.debug("ProbeProxy :: Unregistering adress %s", str(address))
        # Cleanup everything
        if self._subscribedEvents.has_key(address):
            event = self._subscribedEvents[address]
            
            if self._registeredCallbacks.has_key(event)\
            and self._registeredCallbacks[event].has_key(address):
                self._registeredCallbacks[event].pop(address)

            if self._registeredCallbacks[event] == {}:
                self._registeredCallbacks.pop(event)

            self._subscribedEvents.pop(address)
        else:
            LOGGER.debug("ProbeProxy :: unsubsribe address %s inconsistency : not registered", address)

    def subscribe(self, event_name, event, notification_cb, event_subscribed_cb, error_cb):
        """
        Register an event listener
        @param event Event to listen for
        @param notification_cb callable that will be called when the event occurs
        @param event_installed_cb callable that will be called once the event is subscribed to
        @param error_cb callable that will be called if the subscription fails
        @return address identifier used for unsubscribing
        """
        LOGGER.debug("ProbeProxy :: Registering event %s", str(hash(event)))
        #if not block:
        #    raise RuntimeError("This function does not allow non-blocking mode yet")

        # TODO elavoie 2009-07-25 When we will allow for patterns both
        # for event types and sources, we will need to revise the lookup
        # mecanism for which callback function to call
        self._probe.subscribe(pickle.dumps(event),
            reply_handler=save_args(self.__update_event, event_name, event, notification_cb, event_subscribed_cb),
            error_handler=save_args(error_cb, event))

    def unsubscribe(self, address, block=True):
        """
        Unregister an event listener
        @param address identifier given by subscribe()
        @param block Force a synchroneous dbus call if True
        @return None
        """
        LOGGER.debug("ProbeProxy :: Unregister adress %s issued", str(address))
        if address in self._subscribedEvents.keys():
            remote_call(self._probe.unsubscribe, (address,),
                return_cb=save_args(self.__clear_event, address),
                block=block)
        else:
            LOGGER.debug("ProbeProxy :: unsubscribe address %s failed : not registered", address)

    def detach(self, block=False):
        """
        Detach the ProbeProxy from it's TProbe. All installed actions and 
        subscribed events should be removed.
        """
        for action_addr in self._actions.keys():
            self.uninstall(action_addr)

        for address in self._subscribedEvents.keys():
            self.unsubscribe(address)


class ProbeManager(object):
    """
    The ProbeManager provides multiplexing across multiple activity ProbeProxies

    For now, it only handles one at a time, though.
    Actually it doesn't do much at all. But it keeps your encapsulation happy
    """
    _LOGGER = logging.getLogger("sugar.tutorius.ProbeManager")

    def __init__(self, proxy_class=ProbeProxy):
        """Constructor
        @param proxy_class Class to use for creating Proxies to activities.
            The class should support the same interface as ProbeProxy. Exists
            to make this class unit-testable by replacing the Proxy with a mock
        """
        dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)

        self._ProxyClass = proxy_class
        self._probes = {}
        self._current_activity = None

        ProbeManager._LOGGER.debug("__init__()")

    def setCurrentActivity(self, activity_id):
        if not activity_id in self._probes:
            raise RuntimeError("Activity not attached")
        self._current_activity = activity_id

    def getCurrentActivity(self):
        return self._current_activity

    currentActivity = property(fget=getCurrentActivity, fset=setCurrentActivity)

    def install(self, action, action_installed_cb, error_cb):
        """
        Install an action on the current activity
        @param action Action to install
        @param action_installed_cb The callback to call once the action is installed
        @param error_cb The callback that will be called if there is an error during installation
        @param block Force a synchroneous dbus call if True
        @return None
        """
        if self.currentActivity:
            return self._first_proxy(self.currentActivity).install(action, action_installed_cb, error_cb)
        else:
            raise RuntimeWarning("No activity attached")

    def update(self, action_address, newaction):
        """
        Update an already installed action's properties and run it again
        @param action_address Action to update
        @param newaction Action to update it with
        @param block Force a synchroneous dbus call if True
        @return None
        """
        if self.currentActivity:
            return self._first_proxy(self.currentActivity).update(action_address, newaction)
        else:
            raise RuntimeWarning("No activity attached")

    def uninstall(self, action_address):
        """
        Uninstall an installed action
        @param action Action to uninstall
        @param block Force a synchroneous dbus call if True
        """
        if self.currentActivity:
            return self._first_proxy(self.currentActivity).uninstall(action_address)
        else:
            raise RuntimeWarning("No activity attached")

    def subscribe(self, event_name, event, notification_cb, event_subscribed_cb, error_cb):
        """
        Register an event listener
        @param event Event to listen for
        @param notification_cb callable that will be called when the event occurs
        @param subscribe_cb callable that will be called once the action has been
                            installed
        @param error_cb callable that will be called if an error happens during
                        installation
        @return address identifier used for unsubscribing
        """
        if self.currentActivity:
            return self._first_proxy(self.currentActivity).subscribe(event_name, event, notification_cb,\
                                                            event_subscribed_cb, error_cb)
        else:
            raise RuntimeWarning("No activity attached")

    def unsubscribe(self, address):
        """
        Unregister an event listener
        @param address identifier given by subscribe()
        @return None
        """
        if self.currentActivity:
            return self._first_proxy(self.currentActivity).unsubscribe(address)
        else:
            raise RuntimeWarning("No activity attached")

    def register_probe(self, process_name, unique_id):
        """ Adds a probe to the known probes, to be used by a tutorial. 

            A generic name for a process (like an Activity) is passed
            so that the execution of a tutorial will use that generic
            name. However, a unique id is also passed to differentiate
            between many instances of the same process.
            
            @param process_name The generic name of a process
            @param unique_id The unique identification associated to this 
                             process
        """
        ProbeManager._LOGGER.debug("register_probe(%s,%s)", process_name, unique_id)
        if process_name not in self._probes: 
            self._probes[process_name] = [(unique_id,self._ProxyClass(process_name, unique_id))]
        else:
            self._probes[process_name].append((unique_id,self._ProxyClass(process_name, unique_id)))
        

    def unregister_probe(self, unique_id):
        """ Remove a probe from the known probes.
            
            @param unique_id The unique identification associated to this 
                             process
        """
        ProbeManager._LOGGER.debug("unregister_probe(%s)", unique_id)
        for process_name, proxies in self._probes.items():
            for id, proxy in proxies:
                if unique_id == id:
                    proxy.detach()
                    proxies.remove((id,proxy))
                if len(proxies) == 0:
                    self._probes.pop(process_name)

    def get_registered_probes_list(self, process_name=None):
        if process_name == None:
            probe_list = []
            for probes in self._probes.itervalues():
                probe_list.extend(probes)
            return probe_list
        else:
            if process_name in self._probes:
                return self._probes[process_name]
            else:
                return []
                    
            

    def _first_proxy(self, process_name):
        """
        Returns the oldest probe connected under the process_name
        @param process_name The generic process name under which the probe
                            is connected
        """
        if process_name in self._probes:
            return self._probes[process_name][0][1]
        else:
            raise RuntimeWarning("No activity attached under '%s'", process_name)