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comparison planemo/lib/python3.7/site-packages/dateutil/tz/_factories.py @ 0:d30785e31577 draft

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"planemo upload commit 6eee67778febed82ddd413c3ca40b3183a3898f1"
author guerler
date Fri, 31 Jul 2020 00:18:57 -0400
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-1:000000000000 0:d30785e31577
1 from datetime import timedelta
2 import weakref
3 from collections import OrderedDict
4
5 from six.moves import _thread
6
7
8 class _TzSingleton(type):
9 def __init__(cls, *args, **kwargs):
10 cls.__instance = None
11 super(_TzSingleton, cls).__init__(*args, **kwargs)
12
13 def __call__(cls):
14 if cls.__instance is None:
15 cls.__instance = super(_TzSingleton, cls).__call__()
16 return cls.__instance
17
18
19 class _TzFactory(type):
20 def instance(cls, *args, **kwargs):
21 """Alternate constructor that returns a fresh instance"""
22 return type.__call__(cls, *args, **kwargs)
23
24
25 class _TzOffsetFactory(_TzFactory):
26 def __init__(cls, *args, **kwargs):
27 cls.__instances = weakref.WeakValueDictionary()
28 cls.__strong_cache = OrderedDict()
29 cls.__strong_cache_size = 8
30
31 cls._cache_lock = _thread.allocate_lock()
32
33 def __call__(cls, name, offset):
34 if isinstance(offset, timedelta):
35 key = (name, offset.total_seconds())
36 else:
37 key = (name, offset)
38
39 instance = cls.__instances.get(key, None)
40 if instance is None:
41 instance = cls.__instances.setdefault(key,
42 cls.instance(name, offset))
43
44 # This lock may not be necessary in Python 3. See GH issue #901
45 with cls._cache_lock:
46 cls.__strong_cache[key] = cls.__strong_cache.pop(key, instance)
47
48 # Remove an item if the strong cache is overpopulated
49 if len(cls.__strong_cache) > cls.__strong_cache_size:
50 cls.__strong_cache.popitem(last=False)
51
52 return instance
53
54
55 class _TzStrFactory(_TzFactory):
56 def __init__(cls, *args, **kwargs):
57 cls.__instances = weakref.WeakValueDictionary()
58 cls.__strong_cache = OrderedDict()
59 cls.__strong_cache_size = 8
60
61 cls.__cache_lock = _thread.allocate_lock()
62
63 def __call__(cls, s, posix_offset=False):
64 key = (s, posix_offset)
65 instance = cls.__instances.get(key, None)
66
67 if instance is None:
68 instance = cls.__instances.setdefault(key,
69 cls.instance(s, posix_offset))
70
71 # This lock may not be necessary in Python 3. See GH issue #901
72 with cls.__cache_lock:
73 cls.__strong_cache[key] = cls.__strong_cache.pop(key, instance)
74
75 # Remove an item if the strong cache is overpopulated
76 if len(cls.__strong_cache) > cls.__strong_cache_size:
77 cls.__strong_cache.popitem(last=False)
78
79 return instance
80