##############################################################################
#
# 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
#
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"""Python implementation of persistent list."""
import sys
from collections import UserList
import persistent
# The slice object you get when you write list[:]
_SLICE_ALL = slice(None, None, None)
[docs]
class PersistentList(UserList, persistent.Persistent):
"""A persistent wrapper for list objects.
Mutating instances of this class will cause them to be marked
as changed and automatically persisted.
.. versionchanged:: 4.5.2
Using the `clear` method, or deleting a slice (e.g., ``del inst[:]`` or
``del inst[x:x]``) now only results in marking the instance as changed
if it actually removed items.
"""
__super_getitem = UserList.__getitem__
__super_setitem = UserList.__setitem__
__super_delitem = UserList.__delitem__
__super_iadd = UserList.__iadd__
__super_imul = UserList.__imul__
__super_append = UserList.append
__super_insert = UserList.insert
__super_pop = UserList.pop
__super_remove = UserList.remove
__super_reverse = UserList.reverse
__super_sort = UserList.sort
__super_extend = UserList.extend
__super_clear = (
UserList.clear
if hasattr(UserList, 'clear')
else lambda inst: inst.__delitem__(_SLICE_ALL)
)
if sys.version_info[:3] < (3, 7, 4): # pragma: no cover
# Prior to 3.7.4, Python 3 failed to properly
# return an instance of the same class.
# See https://bugs.python.org/issue27639
# and https://github.com/zopefoundation/persistent/issues/112.
# We only define the special method on the necessary versions to avoid
# any speed penalty.
def __getitem__(self, item):
result = self.__super_getitem(item)
if isinstance(item, slice):
result = self.__class__(result)
return result
if sys.version_info[:3] < (3, 7, 4): # pragma: no cover
# Likewise for __copy__.
# See
# https://github.com/python/cpython/commit/3645d29a1dc2102fdb0f5f0c0129ff2295bcd768
def __copy__(self):
inst = self.__class__.__new__(self.__class__)
inst.__dict__.update(self.__dict__)
# Create a copy and avoid triggering descriptors
inst.__dict__["data"] = self.__dict__["data"][:]
return inst
def __setitem__(self, i, item):
self.__super_setitem(i, item)
self._p_changed = 1
def __delitem__(self, i):
# If they write del list[:] but we're empty,
# no need to mark us changed. Likewise with
# a slice that's empty, like list[1:1].
len_before = len(self.data)
self.__super_delitem(i)
if len(self.data) != len_before:
self._p_changed = 1
def __iadd__(self, other):
L = self.__super_iadd(other)
self._p_changed = 1
return L
def __imul__(self, n):
L = self.__super_imul(n)
self._p_changed = 1
return L
[docs]
def append(self, item):
self.__super_append(item)
self._p_changed = 1
[docs]
def clear(self):
"""
Remove all items from the list.
.. versionchanged:: 4.5.2
Now marks the list as changed.
"""
needs_changed = bool(self)
self.__super_clear()
if needs_changed:
self._p_changed = 1
[docs]
def insert(self, i, item):
self.__super_insert(i, item)
self._p_changed = 1
[docs]
def pop(self, i=-1):
rtn = self.__super_pop(i)
self._p_changed = 1
return rtn
[docs]
def remove(self, item):
self.__super_remove(item)
self._p_changed = 1
[docs]
def reverse(self):
self.__super_reverse()
self._p_changed = 1
def sort(self, *args, **kwargs):
self.__super_sort(*args, **kwargs)
self._p_changed = 1
[docs]
def extend(self, other):
self.__super_extend(other)
self._p_changed = 1