git.maemo.org Git - theonering/blob - src/gvoice/state_machine.py

   1 #!/usr/bin/env python
   2
   3 """
   4 @todo Look into switching from POLL_TIME = min(F * 2^n, MAX) to POLL_TIME = min(CONST + F * 2^n, MAX)
   5 @todo Look into supporting more states that have a different F and MAX
   6 """
   7
   8 import logging
   9
  10 import gobject
  11
  12 import util.go_utils as gobject_utils
  13 import util.coroutines as coroutines
  14 import gtk_toolbox
  15
  16
  17 _moduleLogger = logging.getLogger("gvoice.state_machine")
  18
  19
  20 def _to_milliseconds(**kwd):
  21         if "milliseconds" in kwd:
  22                 return kwd["milliseconds"]
  23         elif "seconds" in kwd:
  24                 return kwd["seconds"] * 1000
  25         elif "minutes" in kwd:
  26                 return kwd["minutes"] * 1000 * 60
  27         raise KeyError("Unknown arg: %r" % kwd)
  28
  29
  30 class StateMachine(object):
  31
  32         STATE_ACTIVE = 0, "active"
  33         STATE_IDLE = 1, "idle"
  34         STATE_DND = 2, "dnd"
  35
  36         _ACTION_UPDATE = "update"
  37         _ACTION_RESET = "reset"
  38         _ACTION_STOP = "stop"
  39
  40         _INITIAL_ACTIVE_PERIOD = int(_to_milliseconds(seconds=5))
  41         _FINAL_ACTIVE_PERIOD = int(_to_milliseconds(minutes=2))
  42         _IDLE_PERIOD = int(_to_milliseconds(minutes=10))
  43         _INFINITE_PERIOD = -1
  44
  45         _IS_DAEMON = True
  46
  47         def __init__(self, initItems, updateItems):
  48                 self._initItems = initItems
  49                 self._updateItems = updateItems
  50
  51                 self._state = self.STATE_ACTIVE
  52                 self._timeoutId = None
  53                 self._currentPeriod = self._INITIAL_ACTIVE_PERIOD
  54                 self._set_initial_period()
  55
  56                 self._callback = coroutines.func_sink(
  57                         coroutines.expand_positional(
  58                                 self._request_reset_timers
  59                         )
  60                 )
  61
  62         def close(self):
  63                 self._callback = None
  64
  65         @gobject_utils.async
  66         @gtk_toolbox.log_exception(_moduleLogger)
  67         def start(self):
  68                 _moduleLogger.info("Starting State Machine")
  69                 for item in self._initItems:
  70                         try:
  71                                 item.update()
  72                         except Exception:
  73                                 _moduleLogger.exception("Initial update failed for %r" % item)
  74                 self._schedule_update()
  75
  76         def stop(self):
  77                 _moduleLogger.info("Stopping an already stopped state machine")
  78                 self._stop_update()
  79
  80         def set_state(self, newState):
  81                 oldState = self._state
  82                 _moduleLogger.info("Transitioning from %s to %s" % (oldState, newState))
  83
  84                 self._state = newState
  85                 self.reset_timers()
  86
  87         def get_state(self):
  88                 return self._state
  89
  90         def reset_timers(self):
  91                 self._reset_timers()
  92
  93         @property
  94         def request_reset_timers(self):
  95                 return self._callback
  96
  97         @gobject_utils.async
  98         @gtk_toolbox.log_exception(_moduleLogger)
  99         def _request_reset_timers(self, *args):
 100                 self.reset_timers()
 101
 102         def _set_initial_period(self):
 103                 self._currentPeriod = self._INITIAL_ACTIVE_PERIOD / 2 # We will double it later
 104
 105         def _schedule_update(self):
 106                 nextTimeout = self._calculate_step(self._state, self._currentPeriod)
 107                 nextTimeout = int(nextTimeout)
 108                 if nextTimeout != self._INFINITE_PERIOD:
 109                         self._timeoutId = gobject.timeout_add(nextTimeout, self._on_timeout)
 110                 _moduleLogger.info("Next update in %s ms" % (nextTimeout, ))
 111                 self._currentPeriod = nextTimeout
 112
 113         def _stop_update(self):
 114                 if self._timeoutId is None:
 115                         return
 116                 gobject.source_remove(self._timeoutId)
 117                 self._timeoutId = None
 118
 119         def _reset_timers(self):
 120                 self._stop_update()
 121                 self._set_initial_period()
 122                 self._schedule_update()
 123
 124         def _on_timeout(self):
 125                 _moduleLogger.info("Update")
 126                 for item in self._updateItems:
 127                         try:
 128                                 item.update(force=True)
 129                         except Exception:
 130                                 _moduleLogger.exception("Update failed for %r" % item)
 131                 self._schedule_update()
 132                 return False # do not continue
 133
 134         @classmethod
 135         def _calculate_step(cls, state, period):
 136                 if state == cls.STATE_ACTIVE:
 137                         return min(period * 2, cls._FINAL_ACTIVE_PERIOD)
 138                 elif state == cls.STATE_IDLE:
 139                         return cls._IDLE_PERIOD
 140                 elif state == cls.STATE_DND:
 141                         return cls._INFINITE_PERIOD
 142                 else:
 143                         raise RuntimeError("Unknown state: %r" % (state, ))