53 lines
1.6 KiB
Python
53 lines
1.6 KiB
Python
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#!/usr/bin/env python
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__author__ = "Abhinav Sarkar <abhinav@abhinavsarkar.net>"
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__version__ = "0.2"
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__license__ = "GNU Lesser General Public License"
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try:
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from threading import Lock
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except ImportError:
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from dummy_threading import Lock
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class Cacheable(object):
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registry = {}
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_lock = Lock()
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def __new__(cls, *args, **kwds):
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subject = None
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if 'subject' in kwds and not cls.__name__.startswith('Weekly'):
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subject = kwds['subject']
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del kwds['subject']
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if 'bypass_registry' in kwds:
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del kwds['bypass_registry']
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inst = object.__new__(cls)
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inst.init(*args, **kwds)
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return inst
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key = cls._hash_func(*args, **kwds)
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if subject is not None:
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key = (hash(subject), key)
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Cacheable._lock.acquire()
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try:
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inst, already_registered = Cacheable.register(object.__new__(cls), key)
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if not already_registered:
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inst.init(*args, **kwds)
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finally:
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Cacheable._lock.release()
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return inst
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@staticmethod
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def register(ob, key):
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if not ob.__class__ in Cacheable.registry:
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Cacheable.registry[ob.__class__] = {}
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if key in Cacheable.registry[ob.__class__]:
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ob = Cacheable.registry[ob.__class__][key]
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#print "already registered: %s" % repr(ob)
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return (ob, True)
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else:
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#print "not already registered: %s" % ob.__class__
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Cacheable.registry[ob.__class__][key] = ob
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return (ob, False)
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