import os
import cPickle as pickle
__all__ = ['autopickle', 'BINMODE']
# whether the pickled files are binary
BINMODE = False
def autopickle(__init__):
"""Decorator for instantiating pickled instances transparently."""
def new__init__(self, *args, **kwds):
picklename = self.getPickleFilename(*args, **kwds)
if os.path.exists(picklename):
newSelf = pickle.load(open(picklename))
assert type(newSelf) is type(self)
# copy newSelf to self
if hasattr(newSelf, '__getstate__'):
state = newSelf.__getstate__()
else:
state = newSelf.__dict__
if hasattr(self, '__setstate__'):
self.__setstate__(state)
else:
self.__dict__.update(state)
else:
__init__(self, *args, **kwds)
picklefile = open(picklename, BINMODE and 'wb' or 'w')
try: pickle.dump(self, picklefile, BINMODE)
finally: picklefile.close()
return new__init__
if __name__ == '__main__':
class Foo(object):
@autopickle
def __init__(self, id):
import time; time.sleep(2)
self.id = id
def getPickleFilename(self, id):
return "%s.dat" % id
print Foo(1)
