Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/model_signing/_hashing/memory.py: 82%

1# Copyright 2024 The Sigstore Authors 

2# 

3# Licensed under the Apache License, Version 2.0 (the "License"); 

4# you may not use this file except in compliance with the License. 

5# You may obtain a copy of the License at 

6# 

7# http://www.apache.org/licenses/LICENSE-2.0 

8# 

9# Unless required by applicable law or agreed to in writing, software 

10# distributed under the License is distributed on an "AS IS" BASIS, 

11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 

12# See the License for the specific language governing permissions and 

13# limitations under the License. 

14 

15"""Digests for memory objects. 

16 

17These can only compute hashes of objects residing in memory, after they get 

18converted to bytes. 

19 

20Example usage: 

21```python 

22>>> hasher = SHA256() 

23>>> hasher.update(b"abcd") 

24>>> digest = hasher.compute() 

25>>> digest.digest_hex 

26'88d4266fd4e6338d13b845fcf289579d209c897823b9217da3e161936f031589' 

27``` 

28 

29Or, passing the data directly in the constructor: 

30```python 

31>>> hasher = SHA256(b"abcd") 

32>>> digest = hasher.compute() 

33>>> digest.digest_hex 

34'88d4266fd4e6338d13b845fcf289579d209c897823b9217da3e161936f031589' 

35``` 

36""" 

37 

38import hashlib 

39 

40from typing_extensions import override 

41 

42from model_signing._hashing import hashing 

43 

44 

45class SHA256(hashing.StreamingHashEngine): 

46 """A wrapper around `hashlib.sha256`.""" 

47 

48 def __init__(self, initial_data: bytes = b""): 

49 """Initializes an instance of a SHA256 hash engine. 

50 

51 Args: 

52 initial_data: Optional initial data to hash. 

53 """ 

54 self._hasher = hashlib.sha256(initial_data) 

55 

56 @override 

57 def update(self, data: bytes) -> None: 

58 self._hasher.update(data) 

59 

60 @override 

61 def reset(self, data: bytes = b"") -> None: 

62 self._hasher = hashlib.sha256(data) 

63 

64 @override 

65 def compute(self) -> hashing.Digest: 

66 return hashing.Digest(self.digest_name, self._hasher.digest()) 

67 

68 @property 

69 @override 

70 def digest_name(self) -> str: 

71 return "sha256" 

72 

73 @property 

74 @override 

75 def digest_size(self) -> int: 

76 return self._hasher.digest_size 

77 

78 

79class BLAKE2(hashing.StreamingHashEngine): 

80 """A wrapper around `hashlib.blake2b`.""" 

81 

82 def __init__(self, initial_data: bytes = b""): 

83 """Initializes an instance of a BLAKE2 hash engine. 

84 

85 Args: 

86 initial_data: Optional initial data to hash. 

87 """ 

88 self._hasher = hashlib.blake2b(initial_data) 

89 

90 @override 

91 def update(self, data: bytes) -> None: 

92 self._hasher.update(data) 

93 

94 @override 

95 def reset(self, data: bytes = b"") -> None: 

96 self._hasher = hashlib.blake2b(data) 

97 

98 @override 

99 def compute(self) -> hashing.Digest: 

100 return hashing.Digest(self.digest_name, self._hasher.digest()) 

101 

102 @property 

103 @override 

104 def digest_name(self) -> str: 

105 return "blake2b" 

106 

107 @property 

108 @override 

109 def digest_size(self) -> int: 

110 return self._hasher.digest_size