Source code for pypet.slots

"""Module containing the superclass having slots"""

__author__ = 'Robert Meyer'

[docs]def get_all_slots(cls): """Iterates through a class' (`cls`) mro to get all slots as a set.""" slots_iterator = (getattr(c, '__slots__', ()) for c in cls.__mro__) # `__slots__` might only be a single string, # so we need to put the strings into a tuple. slots_converted = ((slots,) if isinstance(slots, str) else slots for slots in slots_iterator) all_slots = set() all_slots.update(*slots_converted) return all_slots
[docs]class MetaSlotMachine(type): """Meta-class that adds the attribute `__all_slots__` to a class. `__all_slots__` is a set that contains all unique slots of a class, including the ones that are inherited from parents. """
[docs] def __init__(cls, name, bases, dictionary): super(MetaSlotMachine, cls).__init__(name, bases, dictionary) cls.__all_slots__ = get_all_slots(cls)
[docs]class HasSlots(object, metaclass=MetaSlotMachine): """Top-class that allows mixing of classes with and without slots. Takes care that instances can still be pickled with the lowest protocol. Moreover, provides a generic `__dir__` method that lists all slots. """ __slots__ = ('__weakref__',) def __getstate__(self): if hasattr(self, '__dict__'): # We don't require that all sub-classes also define slots, # so they may provide a dictionary statedict = self.__dict__.copy() else: statedict = {} # Get all slots of potential parent classes for slot in self.__all_slots__: try: value = getattr(self, slot) statedict[slot] = value except AttributeError: pass # Pop slots that cannot or should not be pickled statedict.pop('__dict__', None) statedict.pop('__weakref__', None) return statedict
[docs] def __setstate__(self, state): """Recalls state for items with slots""" for key in state: setattr(self, key, state[key])
[docs] def __dir__(self): """Includes all slots in the `dir` method""" result = set() result.update(dir(self.__class__), self.__all_slots__) if hasattr(self, '__dict__'): result.update(self.__dict__.keys()) return list(result)