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# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
import abc
import enum
import sys
import types
import typing
import warnings
# We use a UserWarning subclass, instead of DeprecationWarning, because CPython
# decided deprecation warnings should be invisble by default.
class CryptographyDeprecationWarning(UserWarning):
pass
# Several APIs were deprecated with no specific end-of-life date because of the
# ubiquity of their use. They should not be removed until we agree on when that
# cycle ends.
DeprecatedIn36 = CryptographyDeprecationWarning
DeprecatedIn37 = CryptographyDeprecationWarning
DeprecatedIn39 = CryptographyDeprecationWarning
def _check_bytes(name: str, value: bytes) -> None:
if not isinstance(value, bytes):
raise TypeError("{} must be bytes".format(name))
def _check_byteslike(name: str, value: bytes) -> None:
try:
memoryview(value)
except TypeError:
raise TypeError("{} must be bytes-like".format(name))
def int_to_bytes(integer: int, length: typing.Optional[int] = None) -> bytes:
return integer.to_bytes(
length or (integer.bit_length() + 7) // 8 or 1, "big"
)
class InterfaceNotImplemented(Exception):
pass
# DeprecatedIn39 -- Our only known consumer is aws-encryption-sdk, but we've
# made this a no-op to avoid breaking old versions.
def verify_interface(
iface: abc.ABCMeta, klass: object, *, check_annotations: bool = False
):
# Exists exclusively for `aws-encryption-sdk` which relies on it existing,
# even though it was never a public API.
pass
class _DeprecatedValue:
def __init__(self, value: object, message: str, warning_class):
self.value = value
self.message = message
self.warning_class = warning_class
class _ModuleWithDeprecations(types.ModuleType):
def __init__(self, module: types.ModuleType):
super().__init__(module.__name__)
self.__dict__["_module"] = module
def __getattr__(self, attr: str) -> object:
obj = getattr(self._module, attr)
if isinstance(obj, _DeprecatedValue):
warnings.warn(obj.message, obj.warning_class, stacklevel=2)
obj = obj.value
return obj
def __setattr__(self, attr: str, value: object) -> None:
setattr(self._module, attr, value)
def __delattr__(self, attr: str) -> None:
obj = getattr(self._module, attr)
if isinstance(obj, _DeprecatedValue):
warnings.warn(obj.message, obj.warning_class, stacklevel=2)
delattr(self._module, attr)
def __dir__(self) -> typing.Sequence[str]:
return ["_module"] + dir(self._module)
def deprecated(
value: object,
module_name: str,
message: str,
warning_class: typing.Type[Warning],
name: typing.Optional[str] = None,
) -> _DeprecatedValue:
module = sys.modules[module_name]
if not isinstance(module, _ModuleWithDeprecations):
sys.modules[module_name] = module = _ModuleWithDeprecations(module)
dv = _DeprecatedValue(value, message, warning_class)
# Maintain backwards compatibility with `name is None` for pyOpenSSL.
if name is not None:
setattr(module, name, dv)
return dv
def cached_property(func: typing.Callable) -> property:
cached_name = "_cached_{}".format(func)
sentinel = object()
def inner(instance: object):
cache = getattr(instance, cached_name, sentinel)
if cache is not sentinel:
return cache
result = func(instance)
setattr(instance, cached_name, result)
return result
return property(inner)
# Python 3.10 changed representation of enums. We use well-defined object
# representation and string representation from Python 3.9.
class Enum(enum.Enum):
def __repr__(self) -> str:
return f"<{self.__class__.__name__}.{self._name_}: {self._value_!r}>"
def __str__(self) -> str:
return f"{self.__class__.__name__}.{self._name_}"
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