mirror of
https://github.com/PiBrewing/craftbeerpi4.git
synced 2024-12-30 17:31:44 +01:00
81 lines
2.5 KiB
Python
81 lines
2.5 KiB
Python
|
from datetime import timedelta
|
||
|
|
import weakref
|
||
|
|
from collections import OrderedDict
|
||
|
|
|
||
|
|
from six.moves import _thread
|
||
|
|
|
||
|
|
|
||
|
|
class _TzSingleton(type):
|
||
|
|
def __init__(cls, *args, **kwargs):
|
||
|
|
cls.__instance = None
|
||
|
|
super(_TzSingleton, cls).__init__(*args, **kwargs)
|
||
|
|
|
||
|
|
def __call__(cls):
|
||
|
|
if cls.__instance is None:
|
||
|
|
cls.__instance = super(_TzSingleton, cls).__call__()
|
||
|
|
return cls.__instance
|
||
|
|
|
||
|
|
|
||
|
|
class _TzFactory(type):
|
||
|
|
def instance(cls, *args, **kwargs):
|
||
|
|
"""Alternate constructor that returns a fresh instance"""
|
||
|
|
return type.__call__(cls, *args, **kwargs)
|
||
|
|
|
||
|
|
|
||
|
|
class _TzOffsetFactory(_TzFactory):
|
||
|
|
def __init__(cls, *args, **kwargs):
|
||
|
|
cls.__instances = weakref.WeakValueDictionary()
|
||
|
|
cls.__strong_cache = OrderedDict()
|
||
|
|
cls.__strong_cache_size = 8
|
||
|
|
|
||
|
|
cls._cache_lock = _thread.allocate_lock()
|
||
|
|
|
||
|
|
def __call__(cls, name, offset):
|
||
|
|
if isinstance(offset, timedelta):
|
||
|
|
key = (name, offset.total_seconds())
|
||
|
|
else:
|
||
|
|
key = (name, offset)
|
||
|
|
|
||
|
|
instance = cls.__instances.get(key, None)
|
||
|
|
if instance is None:
|
||
|
|
instance = cls.__instances.setdefault(key,
|
||
|
|
cls.instance(name, offset))
|
||
|
|
|
||
|
|
# This lock may not be necessary in Python 3. See GH issue #901
|
||
|
|
with cls._cache_lock:
|
||
|
|
cls.__strong_cache[key] = cls.__strong_cache.pop(key, instance)
|
||
|
|
|
||
|
|
# Remove an item if the strong cache is overpopulated
|
||
|
|
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 = weakref.WeakValueDictionary()
|
||
|
|
cls.__strong_cache = OrderedDict()
|
||
|
|
cls.__strong_cache_size = 8
|
||
|
|
|
||
|
|
cls.__cache_lock = _thread.allocate_lock()
|
||
|
|
|
||
|
|
def __call__(cls, s, posix_offset=False):
|
||
|
|
key = (s, posix_offset)
|
||
|
|
instance = cls.__instances.get(key, None)
|
||
|
|
|
||
|
|
if instance is None:
|
||
|
|
instance = cls.__instances.setdefault(key,
|
||
|
|
cls.instance(s, posix_offset))
|
||
|
|
|
||
|
|
# This lock may not be necessary in Python 3. See GH issue #901
|
||
|
|
with cls.__cache_lock:
|
||
|
|
cls.__strong_cache[key] = cls.__strong_cache.pop(key, instance)
|
||
|
|
|
||
|
|
# Remove an item if the strong cache is overpopulated
|
||
|
|
if len(cls.__strong_cache) > cls.__strong_cache_size:
|
||
|
|
cls.__strong_cache.popitem(last=False)
|
||
|
|
|
||
|
|
return instance
|
||
|
|
|