Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/cryptography/utils.py: 63%

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 

29DeprecatedIn47 = CryptographyDeprecationWarning 

30 

31 

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

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

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

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

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

37 

38 

39def _check_bytes(name: str, value: bytes) -> None: 

40 if not isinstance(value, bytes): 

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

42 

43 

44def _check_byteslike(name: str, value: Buffer) -> None: 

45 try: 

46 memoryview(value) 

47 except TypeError: 

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

49 

50 

51def int_to_bytes(integer: int, length: int | None = None) -> bytes: 

52 if length == 0: 

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

54 return integer.to_bytes( 

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

56 ) 

57 

58 

59class InterfaceNotImplemented(Exception): 

60 pass 

61 

62 

63class _DeprecatedValue: 

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

65 self.value = value 

66 self.message = message 

67 self.warning_class = warning_class 

68 

69 

70class _ModuleWithDeprecations(types.ModuleType): 

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

72 super().__init__(module.__name__) 

73 self.__dict__["_module"] = module 

74 

75 def __getattr__(self, name: str) -> typing.Any: 

76 obj = getattr(self._module, name) 

77 if isinstance(obj, _DeprecatedValue): 

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

79 obj = obj.value 

80 return obj 

81 

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

83 setattr(self._module, attr, value) 

84 

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

86 obj = getattr(self._module, attr) 

87 if isinstance(obj, _DeprecatedValue): 

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

89 

90 delattr(self._module, attr) 

91 

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

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

94 

95 

96def deprecated( 

97 value: object, 

98 module_name: str, 

99 message: str, 

100 warning_class: type[Warning], 

101 name: str | None = None, 

102) -> _DeprecatedValue: 

103 module = sys.modules[module_name] 

104 if not isinstance(module, _ModuleWithDeprecations): 

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

106 dv = _DeprecatedValue(value, message, warning_class) 

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

108 if name is not None: 

109 setattr(module, name, dv) 

110 return dv 

111 

112 

113def cached_property(func: Callable) -> property: 

114 cached_name = f"_cached_{func}" 

115 sentinel = object() 

116 

117 def inner(instance: object): 

118 cache = getattr(instance, cached_name, sentinel) 

119 if cache is not sentinel: 

120 return cache 

121 result = func(instance) 

122 setattr(instance, cached_name, result) 

123 return result 

124 

125 return property(inner) 

126 

127 

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

129# representation and string representation from Python 3.9. 

130class Enum(enum.Enum): 

131 def __repr__(self) -> str: 

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

133 

134 def __str__(self) -> str: 

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