fpickle_setup.py

"""
The purpose of this file is to allow instancemethods to be pickable.
This is needed in setup.py only and not installed anywhere, thus is not
a library file. It solves the issue from #11874.
"""

import types, copy_reg, copy


# The following four methods are taken from twisted.persisted.styles
# into sage.misc.fpickle, and then here. It was needed due to
# chicken vs egg issue, as we cannot use sage.misc.fpickle in
# setup.py of sage-***.spkg
def pickleMethod(method):
    'support function for copy_reg to pickle method refs'
    return unpickleMethod, (method.im_func.__name__,
                             method.im_self,
                             method.im_class)

def unpickleMethod(im_name,
                    im_self,
                    im_class):
    'support function for copy_reg to unpickle method refs'
    try:
        unbound = getattr(im_class,im_name)
        if im_self is None:
            return unbound
        bound=types.MethodType(unbound.im_func,
                                 im_self)
        return bound
    except AttributeError:
        # assert im_self is not None,"No recourse: no instance to guess from."
        # Attempt a common fix before bailing -- if classes have
        # changed around since we pickled this method, we may still be
        # able to get it by looking on the instance's current class.
        unbound = getattr(im_self.__class__,im_name)
        if im_self is None:
            return unbound
        bound=types.MethodType(unbound.im_func,
                                 im_self)
        return bound

copy_reg.pickle(types.MethodType,
                pickleMethod,
                unpickleMethod)

oldModules = {}

def pickleModule(module):
    'support function for copy_reg to pickle module refs'
    return unpickleModule, (module.__name__,)

def unpickleModule(name):
    'support function for copy_reg to unpickle module refs'
    if oldModules.has_key(name):
        name = oldModules[name]
    return __import__(name,{},{},'x')

copy_reg.pickle(types.ModuleType,
                pickleModule,
                unpickleModule)