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