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 = "active"
  33         STATE_IDLE = "idle"
  34         STATE_DND = "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         @gobject_utils.async
  63         @gtk_toolbox.log_exception(_moduleLogger)
  64         def start(self):
  65                 _moduleLogger.info("Starting State Machine")
  66                 for item in self._initItems:
  67                         try:
  68                                 item.update()
  69                         except Exception:
  70                                 _moduleLogger.exception("Initial update failed for %r" % item)
  71                 self._schedule_update()
  72
  73         def stop(self):
  74                 _moduleLogger.info("Stopping an already stopped state machine")
  75                 self._stop_update()
  76
  77         def set_state(self, state):
  78                 self._state = state
  79                 self.reset_timers()
  80
  81         def get_state(self):
  82                 return self._state
  83
  84         def reset_timers(self):
  85                 self._reset_timers()
  86
  87         @property
  88         def request_reset_timers(self):
  89                 return self._callback
  90
  91         @gobject_utils.async
  92         @gtk_toolbox.log_exception(_moduleLogger)
  93         def _request_reset_timers(self, *args):
  94                 self.reset_timers()
  95
  96         def _set_initial_period(self):
  97                 self._currentPeriod = self._INITIAL_ACTIVE_PERIOD / 2 # We will double it later
  98
  99         def _schedule_update(self):
 100                 nextTimeout = self._calculate_step(self._state, self._currentPeriod)
 101                 nextTimeout = int(nextTimeout)
 102                 if nextTimeout != self._INFINITE_PERIOD:
 103                         self._timeoutId = gobject.timeout_add(nextTimeout, self._on_timeout)
 104                 self._currentPeriod = nextTimeout
 105
 106         def _stop_update(self):
 107                 if self._timeoutId is None:
 108                         return
 109                 gobject.source_remove(self._timeoutId)
 110                 self._timeoutId = None
 111
 112         def _reset_timers(self):
 113                 self._stop_update()
 114                 self._set_initial_period()
 115                 self._schedule_update()
 116
 117         def _on_timeout(self):
 118                 _moduleLogger.info("Update")
 119                 for item in self._updateItems:
 120                         try:
 121                                 item.update(force=True)
 122                         except Exception:
 123                                 _moduleLogger.exception("Update failed for %r" % item)
 124                 self._schedule_update()
 125                 return False # do not continue
 126
 127         @classmethod
 128         def _calculate_step(cls, state, period):
 129                 if state == cls.STATE_ACTIVE:
 130                         return min(period * 2, cls._FINAL_ACTIVE_PERIOD)
 131                 elif state == cls.STATE_IDLE:
 132                         return cls._IDLE_PERIOD
 133                 elif state == cls.STATE_DND:
 134                         return cls._INFINITE_PERIOD
 135                 else:
 136                         raise RuntimeError("Unknown state: %r" % (state, ))