diff options
Diffstat (limited to 'dateutil/tz/_factories.py')
| -rw-r--r-- | dateutil/tz/_factories.py | 28 |
1 files changed, 26 insertions, 2 deletions
diff --git a/dateutil/tz/_factories.py b/dateutil/tz/_factories.py index de2e0c1..d2560eb 100644 --- a/dateutil/tz/_factories.py +++ b/dateutil/tz/_factories.py @@ -1,4 +1,6 @@ from datetime import timedelta +import weakref +from collections import OrderedDict class _TzSingleton(type): @@ -11,6 +13,7 @@ class _TzSingleton(type): cls.__instance = super(_TzSingleton, cls).__call__() return cls.__instance + class _TzFactory(type): def instance(cls, *args, **kwargs): """Alternate constructor that returns a fresh instance""" @@ -19,7 +22,9 @@ class _TzFactory(type): class _TzOffsetFactory(_TzFactory): def __init__(cls, *args, **kwargs): - cls.__instances = {} + cls.__instances = weakref.WeakValueDictionary() + cls.__strong_cache = OrderedDict() + cls.__strong_cache_size = 8 def __call__(cls, name, offset): if isinstance(offset, timedelta): @@ -31,12 +36,22 @@ class _TzOffsetFactory(_TzFactory): if instance is None: instance = cls.__instances.setdefault(key, cls.instance(name, offset)) + + cls.__strong_cache[key] = cls.__strong_cache.pop(key, instance) + + # Remove an item if the strong cache is overpopulated + # TODO: Maybe this should be under a lock? + if len(cls.__strong_cache) > cls.__strong_cache_size: + cls.__strong_cache.popitem(last=False) + return instance class _TzStrFactory(_TzFactory): def __init__(cls, *args, **kwargs): - cls.__instances = {} + cls.__instances = weakref.WeakValueDictionary() + cls.__strong_cache = OrderedDict() + cls.__strong_cache_size = 8 def __call__(cls, s, posix_offset=False): key = (s, posix_offset) @@ -45,5 +60,14 @@ class _TzStrFactory(_TzFactory): if instance is None: instance = cls.__instances.setdefault(key, cls.instance(s, posix_offset)) + + cls.__strong_cache[key] = cls.__strong_cache.pop(key, instance) + + + # Remove an item if the strong cache is overpopulated + # TODO: Maybe this should be under a lock? + if len(cls.__strong_cache) > cls.__strong_cache_size: + cls.__strong_cache.popitem(last=False) + return instance |