Source code for openstack_dashboard.openstack.common.local

# vim: tabstop=4 shiftwidth=4 softtabstop=4

# Copyright 2011 OpenStack Foundation.
# All Rights Reserved.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

"""Greenthread local storage of variables using weak references"""

import weakref

from eventlet import corolocal


[docs]class WeakLocal(corolocal.local): def __getattribute__(self, attr): rval = corolocal.local.__getattribute__(self, attr) if rval: # NOTE(mikal): this bit is confusing. What is stored is a weak # reference, not the value itself. We therefore need to lookup # the weak reference and return the inner value here. rval = rval() return rval def __setattr__(self, attr, value): value = weakref.ref(value) return corolocal.local.__setattr__(self, attr, value) # NOTE(mikal): the name "store" should be deprecated in the future
store = WeakLocal() # A "weak" store uses weak references and allows an object to fall out of scope # when it falls out of scope in the code that uses the thread local storage. A # "strong" store will hold a reference to the object so that it never falls out # of scope. weak_store = WeakLocal() strong_store = corolocal.local