Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/cryptography/utils.py: 66%

1# This file is dual licensed under the terms of the Apache License, Version 

2# 2.0, and the BSD License. See the LICENSE file in the root of this repository 

3# for complete details. 

4 

5from __future__ import annotations 

6 

7import enum 

8import sys 

9import types 

10import typing 

11import warnings 

12from collections.abc import Callable, Sequence 

13 

14 

15# We use a UserWarning subclass, instead of DeprecationWarning, because CPython 

16# decided deprecation warnings should be invisible by default. 

17class CryptographyDeprecationWarning(UserWarning): 

18 pass 

19 

20 

21# Several APIs were deprecated with no specific end-of-life date because of the 

22# ubiquity of their use. They should not be removed until we agree on when that 

23# cycle ends. 

24DeprecatedIn36 = CryptographyDeprecationWarning 

25DeprecatedIn40 = CryptographyDeprecationWarning 

26DeprecatedIn41 = CryptographyDeprecationWarning 

27DeprecatedIn42 = CryptographyDeprecationWarning 

28DeprecatedIn43 = CryptographyDeprecationWarning 

29 

30 

31# If you're wondering why we don't use `Buffer`, it's because `Buffer` would 

32# be more accurately named: Bufferable. It means something which has an 

33# `__buffer__`. Which means you can't actually treat the result as a buffer 

34# (and do things like take a `len()`). 

35if sys.version_info >= (3, 9): 

36 Buffer = typing.Union[bytes, bytearray, memoryview] 

37else: 

38 Buffer = typing.ByteString 

39 

40 

41def _check_bytes(name: str, value: bytes) -> None: 

42 if not isinstance(value, bytes): 

43 raise TypeError(f"{name} must be bytes") 

44 

45 

46def _check_byteslike(name: str, value: Buffer) -> None: 

47 try: 

48 memoryview(value) 

49 except TypeError: 

50 raise TypeError(f"{name} must be bytes-like") 

51 

52 

53def int_to_bytes(integer: int, length: int | None = None) -> bytes: 

54 if length == 0: 

55 raise ValueError("length argument can't be 0") 

56 return integer.to_bytes( 

57 length or (integer.bit_length() + 7) // 8 or 1, "big" 

58 ) 

59 

60 

61class InterfaceNotImplemented(Exception): 

62 pass 

63 

64 

65class _DeprecatedValue: 

66 def __init__(self, value: object, message: str, warning_class): 

67 self.value = value 

68 self.message = message 

69 self.warning_class = warning_class 

70 

71 

72class _ModuleWithDeprecations(types.ModuleType): 

73 def __init__(self, module: types.ModuleType): 

74 super().__init__(module.__name__) 

75 self.__dict__["_module"] = module 

76 

77 def __getattr__(self, attr: str) -> object: 

78 obj = getattr(self._module, attr) 

79 if isinstance(obj, _DeprecatedValue): 

80 warnings.warn(obj.message, obj.warning_class, stacklevel=2) 

81 obj = obj.value 

82 return obj 

83 

84 def __setattr__(self, attr: str, value: object) -> None: 

85 setattr(self._module, attr, value) 

86 

87 def __delattr__(self, attr: str) -> None: 

88 obj = getattr(self._module, attr) 

89 if isinstance(obj, _DeprecatedValue): 

90 warnings.warn(obj.message, obj.warning_class, stacklevel=2) 

91 

92 delattr(self._module, attr) 

93 

94 def __dir__(self) -> Sequence[str]: 

95 return ["_module", *dir(self._module)] 

96 

97 

98def deprecated( 

99 value: object, 

100 module_name: str, 

101 message: str, 

102 warning_class: type[Warning], 

103 name: str | None = None, 

104) -> _DeprecatedValue: 

105 module = sys.modules[module_name] 

106 if not isinstance(module, _ModuleWithDeprecations): 

107 sys.modules[module_name] = module = _ModuleWithDeprecations(module) 

108 dv = _DeprecatedValue(value, message, warning_class) 

109 # Maintain backwards compatibility with `name is None` for pyOpenSSL. 

110 if name is not None: 

111 setattr(module, name, dv) 

112 return dv 

113 

114 

115def cached_property(func: Callable) -> property: 

116 cached_name = f"_cached_{func}" 

117 sentinel = object() 

118 

119 def inner(instance: object): 

120 cache = getattr(instance, cached_name, sentinel) 

121 if cache is not sentinel: 

122 return cache 

123 result = func(instance) 

124 setattr(instance, cached_name, result) 

125 return result 

126 

127 return property(inner) 

128 

129 

130# Python 3.10 changed representation of enums. We use well-defined object 

131# representation and string representation from Python 3.9. 

132class Enum(enum.Enum): 

133 def __repr__(self) -> str: 

134 return f"<{self.__class__.__name__}.{self._name_}: {self._value_!r}>" 

135 

136 def __str__(self) -> str: 

137 return f"{self.__class__.__name__}.{self._name_}"