Current File : //lib/python3/dist-packages/dns/immutable.py
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
import collections.abc
from typing import Any, Callable
from dns._immutable_ctx import immutable
@immutable
class Dict(collections.abc.Mapping): # lgtm[py/missing-equals]
def __init__(
self,
dictionary: Any,
no_copy: bool = False,
map_factory: Callable[[], collections.abc.MutableMapping] = dict,
):
"""Make an immutable dictionary from the specified dictionary.
If *no_copy* is `True`, then *dictionary* will be wrapped instead
of copied. Only set this if you are sure there will be no external
references to the dictionary.
"""
if no_copy and isinstance(dictionary, collections.abc.MutableMapping):
self._odict = dictionary
else:
self._odict = map_factory()
self._odict.update(dictionary)
self._hash = None
def __getitem__(self, key):
return self._odict.__getitem__(key)
def __hash__(self): # pylint: disable=invalid-hash-returned
if self._hash is None:
h = 0
for key in sorted(self._odict.keys()):
h ^= hash(key)
object.__setattr__(self, "_hash", h)
# this does return an int, but pylint doesn't figure that out
return self._hash
def __len__(self):
return len(self._odict)
def __iter__(self):
return iter(self._odict)
def constify(o: Any) -> Any:
"""
Convert mutable types to immutable types.
"""
if isinstance(o, bytearray):
return bytes(o)
if isinstance(o, tuple):
try:
hash(o)
return o
except Exception:
return tuple(constify(elt) for elt in o)
if isinstance(o, list):
return tuple(constify(elt) for elt in o)
if isinstance(o, dict):
cdict = dict()
for k, v in o.items():
cdict[k] = constify(v)
return Dict(cdict, True)
return o
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