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##############################################################################
#
# Copyright (c) 2001, 2002 Zope Foundation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE
#
##############################################################################
"""Python implementation of persistent base types
$Id$"""
import persistent
from persistent._compat import IterableUserDict
class default(object):
def __init__(self, func):
self.func = func
def __get__(self, inst, class_):
if inst is None:
return self
return self.func(inst)
class PersistentMapping(IterableUserDict, persistent.Persistent):
"""A persistent wrapper for mapping objects.
This class allows wrapping of mapping objects so that object
changes are registered. As a side effect, mapping objects may be
subclassed.
A subclass of PersistentMapping or any code that adds new
attributes should not create an attribute named _container. This
is reserved for backwards compatibility reasons.
"""
# UserDict provides all of the mapping behavior. The
# PersistentMapping class is responsible marking the persistent
# state as changed when a method actually changes the state. At
# the mapping API evolves, we may need to add more methods here.
__super_delitem = IterableUserDict.__delitem__
__super_setitem = IterableUserDict.__setitem__
__super_clear = IterableUserDict.clear
__super_update = IterableUserDict.update
__super_setdefault = IterableUserDict.setdefault
__super_pop = IterableUserDict.pop
__super_popitem = IterableUserDict.popitem
def __delitem__(self, key):
self.__super_delitem(key)
self._p_changed = 1
def __setitem__(self, key, v):
self.__super_setitem(key, v)
self._p_changed = 1
def clear(self):
self.__super_clear()
self._p_changed = 1
def update(self, b):
self.__super_update(b)
self._p_changed = 1
def setdefault(self, key, failobj=None):
# We could inline all of UserDict's implementation into the
# method here, but I'd rather not depend at all on the
# implementation in UserDict (simple as it is).
if not key in self.data:
self._p_changed = 1
return self.__super_setdefault(key, failobj)
def pop(self, key, *args):
self._p_changed = 1
return self.__super_pop(key, *args)
def popitem(self):
self._p_changed = 1
return self.__super_popitem()
# Old implementations used _container rather than data.
# Use a descriptor to provide data when we have _container instead
@default
def data(self):
# We don't want to cause a write on read, so wer're careful not to
# do anything that would cause us to become marked as changed, however,
# if we're modified, then the saved record will have data, not
# _container.
data = self.__dict__.pop('_container')
self.__dict__['data'] = data
return data
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