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lvm2/daemons/lvmdbusd/automatedproperties.py

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2016-02-18 02:53:35 +03:00
# Copyright (C) 2015-2016 Red Hat, Inc. All rights reserved.
#
# This copyrighted material is made available to anyone wishing to use,
# modify, copy, or redistribute it subject to the terms and conditions
# of the GNU General Public License v.2.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import dbus
import dbus.service
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from . import cfg
from .utils import get_properties, add_properties, get_object_property_diff, \
log_debug
from .state import State
# noinspection PyPep8Naming,PyUnresolvedReferences
class AutomatedProperties(dbus.service.Object):
"""
This class implements the needed interfaces for:
org.freedesktop.DBus.Properties
Other classes inherit from it to get the same behavior
"""
def __init__(self, object_path, search_method=None):
dbus.service.Object.__init__(self, cfg.bus, object_path)
self._ap_interface = []
self._ap_o_path = object_path
self._ap_search_method = search_method
self.state = None
def dbus_object_path(self):
return self._ap_o_path
def emit_data(self):
props = {}
for i in self.interface():
props[i] = AutomatedProperties._get_all_prop(self, i)
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return self._ap_o_path, props
def set_interface(self, interface):
"""
With inheritance we can't easily tell what interfaces a class provides
so we will have each class that implements an interface tell the
base AutomatedProperties what it is they do provide. This is kind of
clunky and perhaps we can figure out a better way to do this later.
:param interface: An interface the object supports
:return:
"""
if interface not in self._ap_interface:
self._ap_interface.append(interface)
# noinspection PyUnusedLocal
def interface(self, all_interfaces=False):
if all_interfaces:
cpy = list(self._ap_interface)
cpy.extend(
["org.freedesktop.DBus.Introspectable",
"org.freedesktop.DBus.Properties"])
return cpy
return self._ap_interface
@staticmethod
def _get_prop(obj, interface_name, property_name):
value = getattr(obj, property_name)
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# Note: If we get an exception in this handler we won't know about it,
# only the side effect of no returned value!
log_debug('Get (%s), type (%s), value(%s)' %
(property_name, str(type(value)), str(value)))
return value
# Properties
# noinspection PyUnusedLocal
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@dbus.service.method(dbus_interface=dbus.PROPERTIES_IFACE,
in_signature='ss', out_signature='v',
async_callbacks=('cb', 'cbe'))
def Get(self, interface_name, property_name, cb, cbe):
# Note: If we get an exception in this handler we won't know about it,
# only the side effect of no returned value!
r = cfg.create_request_entry(
-1, AutomatedProperties._get_prop,
(self, interface_name, property_name),
cb, cbe, False)
cfg.worker_q.put(r)
@staticmethod
def _get_all_prop(obj, interface_name):
if interface_name in obj.interface(True):
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# Using introspection, lets build this dynamically
properties = get_properties(obj)
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if interface_name in properties:
return properties[interface_name][1]
return {}
raise dbus.exceptions.DBusException(
obj._ap_interface,
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'The object %s does not implement the %s interface'
% (self.__class__, interface_name))
@dbus.service.method(dbus_interface=dbus.PROPERTIES_IFACE,
in_signature='s', out_signature='a{sv}',
async_callbacks=('cb', 'cbe'))
def GetAll(self, interface_name, cb, cbe):
r = cfg.create_request_entry(
-1, AutomatedProperties._get_all_prop,
(self, interface_name),
cb, cbe, False)
cfg.worker_q.put(r)
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@dbus.service.method(dbus_interface=dbus.PROPERTIES_IFACE,
in_signature='ssv')
def Set(self, interface_name, property_name, new_value):
setattr(self, property_name, new_value)
self.PropertiesChanged(interface_name,
{property_name: new_value}, [])
# As dbus-python does not support introspection for properties we will
# get the autogenerated xml and then add our wanted properties to it.
@dbus.service.method(dbus_interface=dbus.INTROSPECTABLE_IFACE,
out_signature='s')
def Introspect(self):
r = dbus.service.Object.Introspect(self, self._ap_o_path, cfg.bus)
# Look at the properties in the class
props = get_properties(self)
for int_f, v in props.items():
r = add_properties(r, int_f, v[0])
return r
@dbus.service.signal(dbus_interface=dbus.PROPERTIES_IFACE,
signature='sa{sv}as')
def PropertiesChanged(self, interface_name, changed_properties,
invalidated_properties):
log_debug(('SIGNAL: PropertiesChanged(%s, %s, %s, %s)' %
(str(self._ap_o_path), str(interface_name),
str(changed_properties), str(invalidated_properties))))
def refresh(self, search_key=None, object_state=None):
"""
Take the values (properties) of an object and update them with what
lvm currently has. You can either fetch the new ones or supply the
new state to be updated with
:param search_key: The value to use to search for
:param object_state: Use this as the new object state
"""
num_changed = 0
# If we can't do a lookup, bail now, this happens if we blindly walk
# through all dbus objects as some don't have a search method, like
# 'Manager' object.
if not self._ap_search_method:
return
search = self.lvm_id
if search_key:
search = search_key
# Either we have the new object state or we need to go fetch it
if object_state:
new_state = object_state
else:
new_state = self._ap_search_method([search])[0]
assert isinstance(new_state, State)
assert new_state
# When we refresh an object the object identifiers might have changed
# because LVM allows the user to change them (name & uuid), thus if
# they have changed we need to update the object manager so that
# look-ups will happen correctly
old_id = self.state.identifiers()
new_id = new_state.identifiers()
if old_id[0] != new_id[0] or old_id[1] != new_id[1]:
cfg.om.lookup_update(self, new_id[0], new_id[1])
# Grab the properties values, then replace the state of the object
# and retrieve the new values.
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o_prop = get_properties(self)
self.state = new_state
n_prop = get_properties(self)
changed = get_object_property_diff(o_prop, n_prop)
if changed:
for int_f, v in changed.items():
self.PropertiesChanged(int_f, v, [])
num_changed += 1
return num_changed