Viewing file:  copy_reg.py (1.92 KB) -rw-r--r--
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"""Helper to provide extensibility for pickle/cPickle.
This is only useful to add pickle support for extension types defined in
C, not for instances of user-defined classes.
"""
from types import ClassType as _ClassType
__all__ = ["pickle","constructor"]
dispatch_table = {}
safe_constructors = {}
def pickle(ob_type, pickle_function, constructor_ob=None):
if type(ob_type) is _ClassType:
raise TypeError("copy_reg is not intended for use with classes")
if not callable(pickle_function):
raise TypeError("reduction functions must be callable")
dispatch_table[ob_type] = pickle_function
if constructor_ob is not None:
constructor(constructor_ob)
def constructor(object):
if not callable(object):
raise TypeError("constructors must be callable")
safe_constructors[object] = 1
# Example: provide pickling support for complex numbers.
def pickle_complex(c):
return complex, (c.real, c.imag)
pickle(type(1j), pickle_complex, complex)
# Support for picking new-style objects
def _reconstructor(cls, base, state):
obj = base.__new__(cls, state)
base.__init__(obj, state)
return obj
_reconstructor.__safe_for_unpickling__ = 1
_HEAPTYPE = 1<<9
def _reduce(self):
for base in self.__class__.__mro__:
if hasattr(base, '__flags__') and not base.__flags__ & _HEAPTYPE:
break
else:
base = object # not really reachable
if base is object:
state = None
else:
if base is self.__class__:
raise TypeError, "can't pickle %s objects" % base.__name__
state = base(self)
args = (self.__class__, base, state)
try:
getstate = self.__getstate__
except AttributeError:
try:
dict = self.__dict__
except AttributeError:
dict = None
else:
dict = getstate()
if dict:
return _reconstructor, args, dict
else:
return _reconstructor, args
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