49 lines
1.4 KiB
Python
49 lines
1.4 KiB
Python
from datetime import timedelta
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class _TzSingleton(type):
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def __init__(cls, *args, **kwargs):
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cls.__instance = None
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super(_TzSingleton, cls).__init__(*args, **kwargs)
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def __call__(cls):
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if cls.__instance is None:
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cls.__instance = super(_TzSingleton, cls).__call__()
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return cls.__instance
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class _TzFactory(type):
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def instance(cls, *args, **kwargs):
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"""Alternate constructor that returns a fresh instance"""
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return type.__call__(cls, *args, **kwargs)
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class _TzOffsetFactory(_TzFactory):
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def __init__(cls, *args, **kwargs):
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cls.__instances = {}
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def __call__(cls, name, offset):
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if isinstance(offset, timedelta):
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key = (name, offset.total_seconds())
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else:
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key = (name, offset)
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instance = cls.__instances.get(key, None)
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if instance is None:
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instance = cls.__instances.setdefault(key,
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cls.instance(name, offset))
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return instance
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class _TzStrFactory(_TzFactory):
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def __init__(cls, *args, **kwargs):
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cls.__instances = {}
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def __call__(cls, s, posix_offset=False):
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key = (s, posix_offset)
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instance = cls.__instances.get(key, None)
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if instance is None:
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instance = cls.__instances.setdefault(key,
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cls.instance(s, posix_offset))
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return instance
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