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##############################################################################
#
# Copyright (c) 2004 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.
#
##############################################################################
"""Persistent component managers.
"""
from persistent import Persistent
from persistent.list import PersistentList
from persistent.mapping import PersistentMapping
from zope.interface.adapter import VerifyingAdapterRegistry
from zope.interface.registry import Components
class PersistentAdapterRegistry(VerifyingAdapterRegistry, Persistent):
"""
An adapter registry that is also a persistent object.
.. versionchanged:: 5.0.0
Internal data structures are now composed of
:class:`persistent.mapping.PersistentMapping` and
:class:`persistent.list.PersistentList`. This helps scale to
larger registries.
Previously they were :class:`dict`, :class:`list` and
:class:`tuple`, meaning that as soon as this object was
unpickled, the entire registry tree had to be unpickled, and
when a change was made (an object registered or unregisterd),
the entire registry had to be pickled. Now, only the parts
that are in use are loaded, and only the parts that are
modified are stored.
The above applies without reservation to newly created
instances. For existing persistent instances, however, the
data will continue to be in dicts and tuples, with some few
exceptions for newly added or changed data.
To fix this, call :meth:`rebuild` and commit the transaction.
This will rewrite the internal data structures to use the new
types.
"""
# The persistent types we use, replacing the basic types inherited
# from ``BaseAdapterRegistry``.
_sequenceType = PersistentList
_leafSequenceType = PersistentList
_mappingType = PersistentMapping
_providedType = PersistentMapping
# The methods needed to manipulate the leaves of the subscriber
# tree. When we're manipulating unmigrated data, it's safe to
# migrate it, but not otherwise (we don't want to write in an
# otherwise read-only transaction).
def _addValueToLeaf(self, existing_leaf_sequence, new_item):
if not existing_leaf_sequence:
existing_leaf_sequence = self._leafSequenceType()
elif isinstance(existing_leaf_sequence, tuple):
# Converting from old state.
existing_leaf_sequence = self._leafSequenceType(
existing_leaf_sequence)
existing_leaf_sequence.append(new_item)
return existing_leaf_sequence
def _removeValueFromLeaf(self, existing_leaf_sequence, to_remove):
if isinstance(existing_leaf_sequence, tuple):
# Converting from old state
existing_leaf_sequence = self._leafSequenceType(
existing_leaf_sequence)
without_removed = VerifyingAdapterRegistry._removeValueFromLeaf(
self,
existing_leaf_sequence,
to_remove)
existing_leaf_sequence[:] = without_removed
return existing_leaf_sequence
def changed(self, originally_changed):
if originally_changed is self:
# XXX: This is almost certainly redundant, even if we
# have old data consisting of plain dict/list/tuple. That's
# because the super class will now increment the ``_generation``
# attribute to keep caches in sync. For this same reason,
# it's not worth trying to "optimize" for the case that we're a
# new or rebuilt object containing only Persistent sub-objects:
# the changed() mechanism will still result in mutating this
# object via ``_generation``.
self._p_changed = True
super().changed(originally_changed)
def __getstate__(self):
state = super().__getstate__().copy()
for name in self._delegated:
state.pop(name, 0)
state.pop('ro', None)
return state
def __setstate__(self, state):
bases = state.pop('__bases__', ())
super().__setstate__(state)
self._createLookup()
self.__bases__ = bases
self._v_lookup.changed(self)
class PersistentComponents(Components):
"""
A component implementation that uses `PersistentAdapterRegistry`.
Note that this object itself is *not* `Persistent`.
"""
def _init_registries(self):
self.adapters = PersistentAdapterRegistry()
self.utilities = PersistentAdapterRegistry()
def _init_registrations(self):
self._utility_registrations = PersistentMapping()
self._adapter_registrations = PersistentMapping()
self._subscription_registrations = PersistentList()
self._handler_registrations = PersistentList()
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