Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/cryptography/utils.py: 64%

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 

5 

6import enum 

7import sys 

8import types 

9import typing 

10import warnings 

11 

12 

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

14# decided deprecation warnings should be invisble by default. 

15class CryptographyDeprecationWarning(UserWarning): 

16 pass 

17 

18 

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

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

21# cycle ends. 

22DeprecatedIn36 = CryptographyDeprecationWarning 

23DeprecatedIn37 = CryptographyDeprecationWarning 

24DeprecatedIn39 = CryptographyDeprecationWarning 

25DeprecatedIn40 = CryptographyDeprecationWarning 

26 

27 

28def _check_bytes(name: str, value: bytes) -> None: 

29 if not isinstance(value, bytes): 

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

31 

32 

33def _check_byteslike(name: str, value: bytes) -> None: 

34 try: 

35 memoryview(value) 

36 except TypeError: 

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

38 

39 

40def int_to_bytes(integer: int, length: typing.Optional[int] = None) -> bytes: 

41 return integer.to_bytes( 

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

43 ) 

44 

45 

46def _extract_buffer_length(obj: typing.Any) -> typing.Tuple[int, int]: 

47 from cryptography.hazmat.bindings._rust import _openssl 

48 

49 buf = _openssl.ffi.from_buffer(obj) 

50 return int(_openssl.ffi.cast("uintptr_t", buf)), len(buf) 

51 

52 

53class InterfaceNotImplemented(Exception): 

54 pass 

55 

56 

57class _DeprecatedValue: 

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

59 self.value = value 

60 self.message = message 

61 self.warning_class = warning_class 

62 

63 

64class _ModuleWithDeprecations(types.ModuleType): 

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

66 super().__init__(module.__name__) 

67 self.__dict__["_module"] = module 

68 

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

70 obj = getattr(self._module, attr) 

71 if isinstance(obj, _DeprecatedValue): 

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

73 obj = obj.value 

74 return obj 

75 

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

77 setattr(self._module, attr, value) 

78 

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

80 obj = getattr(self._module, attr) 

81 if isinstance(obj, _DeprecatedValue): 

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

83 

84 delattr(self._module, attr) 

85 

86 def __dir__(self) -> typing.Sequence[str]: 

87 return ["_module"] + dir(self._module) 

88 

89 

90def deprecated( 

91 value: object, 

92 module_name: str, 

93 message: str, 

94 warning_class: typing.Type[Warning], 

95 name: typing.Optional[str] = None, 

96) -> _DeprecatedValue: 

97 module = sys.modules[module_name] 

98 if not isinstance(module, _ModuleWithDeprecations): 

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

100 dv = _DeprecatedValue(value, message, warning_class) 

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

102 if name is not None: 

103 setattr(module, name, dv) 

104 return dv 

105 

106 

107def cached_property(func: typing.Callable) -> property: 

108 cached_name = f"_cached_{func}" 

109 sentinel = object() 

110 

111 def inner(instance: object): 

112 cache = getattr(instance, cached_name, sentinel) 

113 if cache is not sentinel: 

114 return cache 

115 result = func(instance) 

116 setattr(instance, cached_name, result) 

117 return result 

118 

119 return property(inner) 

120 

121 

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

123# representation and string representation from Python 3.9. 

124class Enum(enum.Enum): 

125 def __repr__(self) -> str: 

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

127 

128 def __str__(self) -> str: 

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