Solaar/lib/solaar/upower.py

82 lines
2.4 KiB
Python

# -*- python-mode -*-
# -*- coding: UTF-8 -*-
## Copyright (C) 2012-2013 Daniel Pavel
##
## 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 Street, Fifth Floor, Boston, MA 02110-1301 USA.
from __future__ import absolute_import, division, print_function, unicode_literals
from logging import getLogger, INFO as _INFO
_log = getLogger(__name__)
del getLogger
#
# As suggested here: http://stackoverflow.com/a/13548984
#
_suspend_callback = None
def _suspend():
if _suspend_callback:
if _log.isEnabledFor(_INFO):
_log.info("received suspend event from UPower")
_suspend_callback()
_resume_callback = None
def _resume():
if _resume_callback:
if _log.isEnabledFor(_INFO):
_log.info("received resume event from UPower")
_resume_callback()
def watch(on_resume_callback, on_suspend_callback):
"""Register callback for suspend/resume events.
They are called only if the system DBus is running, and the UPower daemon is available."""
global _resume_callback, _suspend_callback
_suspend_callback = on_suspend_callback
_resume_callback = on_resume_callback
try:
import dbus
_UPOWER_BUS = 'org.freedesktop.UPower'
_UPOWER_INTERFACE = 'org.freedesktop.UPower'
# integration into the main GLib loop
from dbus.mainloop.glib import DBusGMainLoop
DBusGMainLoop(set_as_default=True)
bus = dbus.SystemBus()
assert bus
bus.add_signal_receiver(_suspend, signal_name='Sleeping',
dbus_interface=_UPOWER_INTERFACE, bus_name=_UPOWER_BUS)
bus.add_signal_receiver(_resume, signal_name='Resuming',
dbus_interface=_UPOWER_INTERFACE, bus_name=_UPOWER_BUS)
if _log.isEnabledFor(_INFO):
_log.info("connected to system dbus, watching for suspend/resume events")
except:
# Either:
# - the dbus library is not available
# - the system dbus is not running
_log.warn("failed to register suspend/resume callbacks")
pass