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 

25DeprecatedIn37 = CryptographyDeprecationWarning 

26DeprecatedIn40 = CryptographyDeprecationWarning 

27DeprecatedIn41 = CryptographyDeprecationWarning 

28DeprecatedIn42 = CryptographyDeprecationWarning 

29DeprecatedIn43 = CryptographyDeprecationWarning 

30DeprecatedIn45 = CryptographyDeprecationWarning 

31 

32 

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

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

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

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

37if sys.version_info >= (3, 9): 

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

39else: 

40 Buffer = typing.ByteString 

41 

42 

43def _check_bytes(name: str, value: bytes) -> None: 

44 if not isinstance(value, bytes): 

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

46 

47 

48def _check_byteslike(name: str, value: Buffer) -> None: 

49 try: 

50 memoryview(value) 

51 except TypeError: 

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

53 

54 

55def int_to_bytes(integer: int, length: int | None = None) -> bytes: 

56 if length == 0: 

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

58 return integer.to_bytes( 

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

60 ) 

61 

62 

63class InterfaceNotImplemented(Exception): 

64 pass 

65 

66 

67class _DeprecatedValue: 

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

69 self.value = value 

70 self.message = message 

71 self.warning_class = warning_class 

72 

73 

74class _ModuleWithDeprecations(types.ModuleType): 

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

76 super().__init__(module.__name__) 

77 self.__dict__["_module"] = module 

78 

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

80 obj = getattr(self._module, attr) 

81 if isinstance(obj, _DeprecatedValue): 

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

83 obj = obj.value 

84 return obj 

85 

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

87 setattr(self._module, attr, value) 

88 

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

90 obj = getattr(self._module, attr) 

91 if isinstance(obj, _DeprecatedValue): 

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

93 

94 delattr(self._module, attr) 

95 

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

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

98 

99 

100def deprecated( 

101 value: object, 

102 module_name: str, 

103 message: str, 

104 warning_class: type[Warning], 

105 name: str | None = None, 

106) -> _DeprecatedValue: 

107 module = sys.modules[module_name] 

108 if not isinstance(module, _ModuleWithDeprecations): 

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

110 dv = _DeprecatedValue(value, message, warning_class) 

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

112 if name is not None: 

113 setattr(module, name, dv) 

114 return dv 

115 

116 

117def cached_property(func: Callable) -> property: 

118 cached_name = f"_cached_{func}" 

119 sentinel = object() 

120 

121 def inner(instance: object): 

122 cache = getattr(instance, cached_name, sentinel) 

123 if cache is not sentinel: 

124 return cache 

125 result = func(instance) 

126 setattr(instance, cached_name, result) 

127 return result 

128 

129 return property(inner) 

130 

131 

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

133# representation and string representation from Python 3.9. 

134class Enum(enum.Enum): 

135 def __repr__(self) -> str: 

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

137 

138 def __str__(self) -> str: 

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