82 lines
2.4 KiB
Python
82 lines
2.4 KiB
Python
## Copyright (C) 2012-2013 Daniel Pavel
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##
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## This program is free software; you can redistribute it and/or modify
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## it under the terms of the GNU General Public License as published by
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## the Free Software Foundation; either version 2 of the License, or
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## (at your option) any later version.
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##
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## This program is distributed in the hope that it will be useful,
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## but WITHOUT ANY WARRANTY; without even the implied warranty of
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## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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## GNU General Public License for more details.
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##
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## You should have received a copy of the GNU General Public License along
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## with this program; if not, write to the Free Software Foundation, Inc.,
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## 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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import logging
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logger = logging.getLogger(__name__)
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#
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# As suggested here: http://stackoverflow.com/a/13548984
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#
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_suspend_callback = None
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def _suspend():
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if _suspend_callback:
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if logger.isEnabledFor(logging.INFO):
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logger.info("received suspend event")
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_suspend_callback()
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_resume_callback = None
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def _resume():
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if _resume_callback:
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if logger.isEnabledFor(logging.INFO):
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logger.info("received resume event")
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_resume_callback()
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def _suspend_or_resume(suspend):
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_suspend() if suspend else _resume()
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def watch(on_resume_callback=None, on_suspend_callback=None):
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"""Register callback for suspend/resume events.
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They are called only if the system DBus is running, and the Login daemon is available."""
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global _resume_callback, _suspend_callback
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_suspend_callback = on_suspend_callback
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_resume_callback = on_resume_callback
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try:
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import dbus
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_LOGIND_BUS = "org.freedesktop.login1"
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_LOGIND_INTERFACE = "org.freedesktop.login1.Manager"
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# integration into the main GLib loop
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from dbus.mainloop.glib import DBusGMainLoop
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DBusGMainLoop(set_as_default=True)
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bus = dbus.SystemBus()
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assert bus
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bus.add_signal_receiver(_suspend_or_resume, "PrepareForSleep", dbus_interface=_LOGIND_INTERFACE, bus_name=_LOGIND_BUS)
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if logger.isEnabledFor(logging.INFO):
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logger.info("connected to system dbus, watching for suspend/resume events")
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except Exception:
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# Either:
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# - the dbus library is not available
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# - the system dbus is not running
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logger.warning("failed to register suspend/resume callbacks")
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pass
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