#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# base.py
"""
Base Classes
"""
#
# Copyright (c) 2020 Dominic Davis-Foster <dominic@davis-foster.co.uk>
# Copyright (c) 2015 Warren Smith
# Copyright (c) Marco Sulla
# Copyright (c) 2012 Santiago Lezica
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
# MA 02110-1301, USA.
#
# stdlib
from abc import abstractmethod
from typing import Any, Mapping, MutableMapping, Optional, Type, TypeVar
# 3rd party
from domdf_python_tools.doctools import is_documented_by # type: ignore # TODO
KT = TypeVar('KT')
VT = TypeVar('VT')
class DictWrapper(Mapping[KT, VT]):
"""
Absrtract Mixin class for classes that wrap a dict object or similar
"""
_dict: dict
def __getitem__(self, key: Any) -> Any:
return self._dict[key]
def __contains__(self, key: Any) -> Any:
return key in self._dict
def __iter__(self): # -> Iterable[Any]:
return iter(self._dict)
def __len__(self) -> int:
return len(self._dict)
def __repr__(self) -> str:
return f'<{self.__class__.__name__} {self._dict!r}>'
@abstractmethod
def copy(self, *args, **kwargs):
pass
def __copy__(self, *args, **kwargs):
return self.copy()
[docs]class FrozenBase(DictWrapper[KT, VT]):
"""
Abstract Base Class for Frozen dictionaries
Used by frozendict and FrozenOrderedDict.
Custom subclasses must implement at a minimum ``__init__``,
``copy``, ``fromkeys``.
"""
dict_cls: Optional[Type] = None
[docs] @abstractmethod
def __init__(self, *args, **kwargs):
self._dict = self.dict_cls(*args, **kwargs)
self._hash = None
[docs] @classmethod
@is_documented_by(dict.fromkeys)
def fromkeys(cls, *args, **kwargs):
return cls(dict.fromkeys(*args, **kwargs))
class MutableBase(DictWrapper[KT, VT], MutableMapping[KT, VT]):
"""
Abstract Base Class for mutable dictionaries
Used by NonelessDict and NonelessOrderedDict.
Custom subclasses must implement at a minimum ``__init__``,
``copy``, ``fromkeys``.
"""
dict_cls = None # type: ignore
@abstractmethod
def __init__(self, *args, **kwargs):
self._dict = self.dict_cls(*args, **kwargs)
self._hash = None
def __setitem__(self, key, value):
if value:
self._dict[key] = value
def __delitem__(self, key):
del self._dict[key]
@classmethod
@is_documented_by(dict.fromkeys)
def fromkeys(cls, *args, **kwargs):
return cls(dict.fromkeys(*args, **kwargs))