src/panucci/services.py

   1 #!/usr/bin/env python
   2 #
   3 # This file is part of Panucci.
   4 # Copyright (c) 2008-2009 The Panucci Audiobook and Podcast Player Project
   5 #
   6 # Panucci is free software: you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation, either version 3 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # Panucci is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with Panucci.  If not, see <http://www.gnu.org/licenses/>.
  18 #
  19 #  from services.py -- Core Services for gPodder
  20 #  Thomas Perl <thp@perli.net>   2007-08-24
  21 #
  22 #  2009-02-13 - nikosapi: made ObservableService more Panucci-esque
  23 #
  24
  25 from logging import getLogger
  26
  27 # the following are only needed for __headphone_watcher
  28 import util
  29 import gobject
  30
  31 class ObservableService(object):
  32     def __init__(self, signal_names=[], log=None):
  33         self.__log = getLogger('ObservableService') if log is None else log
  34
  35         self.observers = {}
  36         for signal in signal_names:
  37             self.observers[signal] = []
  38
  39         if not signal_names:
  40             self.__log.warning('No signal names defined...')
  41
  42     def register(self, signal_name, observer):
  43         if signal_name in self.observers:
  44             if not observer in self.observers[signal_name]:
  45                 self.observers[signal_name].append(observer)
  46                 self.__log.debug( 'Registered "%s" as an observer for "%s"',
  47                     observer.__name__, signal_name )
  48             else:
  49                 self.__log.warning(
  50                     'Observer "%s" is already added to signal "%s"',
  51                     observer.__name__, signal_name )
  52         else:
  53             self.__log.warning(
  54                 'Signal "%s" is not available for registration', signal_name )
  55
  56     def unregister(self, signal_name, observer):
  57         if signal_name in self.observers:
  58             if observer in self.observers[signal_name]:
  59                 self.observers[signal_name].remove(observer)
  60                 self.__log.debug( 'Unregistered "%s" as an observer for "%s"',
  61                     observer.__name__, signal_name )
  62             else:
  63                 self.__log.warning(
  64                     'Observer "%s" could not be removed from signal "%s"',
  65                     observer.__name__, signal_name )
  66         else:
  67             self.__log.warning(
  68                 'Signal "%s" is not available for un-registration.',
  69                 signal_name )
  70
  71     def notify(self, signal_name, *args, **kwargs):
  72         caller = kwargs.get('caller')
  73         caller = 'UnknownCaller' if caller is None else caller.__name__
  74         rtn_value = False
  75
  76         if signal_name in self.observers:
  77             self.__log.debug(
  78                 'Sending signal "%s" for caller "%s"', signal_name, caller )
  79
  80             rtn_value = True
  81             for observer in self.observers[signal_name]:
  82                 rtn_value &= bool(observer( *args ))
  83         else:
  84             self.__log.warning(
  85                 'Signal "%s" (from caller "%s") is not available '
  86                 'for notification', signal_name, caller )
  87
  88         return rtn_value
  89
  90
  91 HEADPHONE_SYS = "/sys/devices/platform/gpio-switch/headphone/state"
  92
  93 class __headphone_watcher(ObservableService):
  94     """ A small service with one singnal that reports whether or not the
  95         headphones are connected. Returns True if the headphones are connected,
  96         False if they're not and None if it's not possible to determine the
  97         headphone status. """
  98
  99     signals = [ 'headphone-status-changed', ]
 100
 101     def __init__(self, sys_file):
 102         self.__log = getLogger('panucci.serivces.__headphone_watcher')
 103         ObservableService.__init__(self, self.signals, self.__log)
 104
 105         self.__is_connected = None
 106
 107         if util.platform == util.MAEMO:
 108             try:
 109                 self.__sys_file = open( sys_file, 'r' )
 110                 self.__is_connected = self.__get_state_from_fd(self.__sys_file)
 111                 gobject.io_add_watch( self.__sys_file, gobject.IO_PRI,
 112                                       self.__on_status_changed )
 113             except IOError:
 114                 self.__log.exception("Can't open headphone status file.")
 115
 116     @property
 117     def is_connected(self):
 118         return self.__is_connected
 119
 120     def __get_state_from_fd(self, fd):
 121         fd.seek(0)
 122         state = fd.read().strip()
 123         return state == 'connected'
 124
 125     def __on_status_changed(self, src, cond):
 126         self.__is_connected = self.__get_state_from_fd( src )
 127         self.__log.debug(
 128             'Headphone state changed (is_connected=%s).', self.__is_connected )
 129         self.notify( 'headphone-status-changed', self.__is_connected,
 130                      caller=self.__on_status_changed )
 131         return True
 132
 133 headphone_service = __headphone_watcher(HEADPHONE_SYS)
 134