Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/tensorflow/python/autograph/pyct/cache.py: 45%

1# Copyright 2016 The TensorFlow Authors. All Rights Reserved. 

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"""Caching utilities.""" 

16 

17import inspect 

18import weakref 

19 

20 

21# TODO(mdan): Add a garbage collection hook for cleaning up modules. 

22class _TransformedFnCache(object): 

23 """Generic hierarchical cache for transformed functions. 

24 

25 The keys are soft references (i.e. they are discarded when the key is 

26 destroyed) created from the source function by `_get_key`. The subkeys are 

27 strong references and can be any value. Typically they identify different 

28 kinds of transformation. 

29 """ 

30 

31 __slots__ = ('_cache',) 

32 

33 def __init__(self): 

34 self._cache = weakref.WeakKeyDictionary() 

35 

36 def _get_key(self, entity): 

37 raise NotImplementedError('subclasses must override') 

38 

39 def has(self, entity, subkey): 

40 key = self._get_key(entity) 

41 parent = self._cache.get(key, None) 

42 if parent is None: 

43 return False 

44 return subkey in parent 

45 

46 def __getitem__(self, entity): 

47 key = self._get_key(entity) 

48 parent = self._cache.get(key, None) 

49 if parent is None: 

50 # The bucket is initialized to support this usage: 

51 # cache[key][subkey] = value 

52 self._cache[key] = parent = {} 

53 return parent 

54 

55 def __len__(self): 

56 return len(self._cache) 

57 

58 

59class CodeObjectCache(_TransformedFnCache): 

60 """A function cache based on code objects. 

61 

62 Code objects are good proxies for the source code of a function. 

63 

64 This cache efficiently handles functions that share code objects, such as 

65 functions defined in a loop, bound methods, etc. 

66 

67 The cache falls back to the function object, if it doesn't have a code object. 

68 """ 

69 

70 def _get_key(self, entity): 

71 if hasattr(entity, '__code__'): 

72 return entity.__code__ 

73 else: 

74 return entity 

75 

76 

77class UnboundInstanceCache(_TransformedFnCache): 

78 """A function cache based on unbound function objects. 

79 

80 Using the function for the cache key allows efficient handling of object 

81 methods. 

82 

83 Unlike the _CodeObjectCache, this discriminates between different functions 

84 even if they have the same code. This is needed for decorators that may 

85 masquerade as another function. 

86 """ 

87 

88 def _get_key(self, entity): 

89 if inspect.ismethod(entity): 

90 return entity.__func__ 

91 return entity 

92 

93