Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/cryptography/utils.py: 62%

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 

12 

13 

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

15# decided deprecation warnings should be invisble by default. 

16class CryptographyDeprecationWarning(UserWarning): 

17 pass 

18 

19 

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

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

22# cycle ends. 

23DeprecatedIn36 = CryptographyDeprecationWarning 

24DeprecatedIn37 = CryptographyDeprecationWarning 

25DeprecatedIn40 = CryptographyDeprecationWarning 

26DeprecatedIn41 = CryptographyDeprecationWarning 

27 

28 

29def _check_bytes(name: str, value: bytes) -> None: 

30 if not isinstance(value, bytes): 

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

32 

33 

34def _check_byteslike(name: str, value: bytes) -> None: 

35 try: 

36 memoryview(value) 

37 except TypeError: 

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

39 

40 

41def int_to_bytes(integer: int, length: typing.Optional[int] = None) -> bytes: 

42 return integer.to_bytes( 

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

44 ) 

45 

46 

47def _extract_buffer_length(obj: typing.Any) -> typing.Tuple[typing.Any, int]: 

48 from cryptography.hazmat.bindings._rust import _openssl 

49 

50 buf = _openssl.ffi.from_buffer(obj) 

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

52 

53 

54class InterfaceNotImplemented(Exception): 

55 pass 

56 

57 

58class _DeprecatedValue: 

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

60 self.value = value 

61 self.message = message 

62 self.warning_class = warning_class 

63 

64 

65class _ModuleWithDeprecations(types.ModuleType): 

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

67 super().__init__(module.__name__) 

68 self.__dict__["_module"] = module 

69 

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

71 obj = getattr(self._module, attr) 

72 if isinstance(obj, _DeprecatedValue): 

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

74 obj = obj.value 

75 return obj 

76 

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

78 setattr(self._module, attr, value) 

79 

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

81 obj = getattr(self._module, attr) 

82 if isinstance(obj, _DeprecatedValue): 

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

84 

85 delattr(self._module, attr) 

86 

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

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

89 

90 

91def deprecated( 

92 value: object, 

93 module_name: str, 

94 message: str, 

95 warning_class: typing.Type[Warning], 

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

97) -> _DeprecatedValue: 

98 module = sys.modules[module_name] 

99 if not isinstance(module, _ModuleWithDeprecations): 

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

101 dv = _DeprecatedValue(value, message, warning_class) 

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

103 if name is not None: 

104 setattr(module, name, dv) 

105 return dv 

106 

107 

108def cached_property(func: typing.Callable) -> property: 

109 cached_name = f"_cached_{func}" 

110 sentinel = object() 

111 

112 def inner(instance: object): 

113 cache = getattr(instance, cached_name, sentinel) 

114 if cache is not sentinel: 

115 return cache 

116 result = func(instance) 

117 setattr(instance, cached_name, result) 

118 return result 

119 

120 return property(inner) 

121 

122 

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

124# representation and string representation from Python 3.9. 

125class Enum(enum.Enum): 

126 def __repr__(self) -> str: 

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

128 

129 def __str__(self) -> str: 

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