Python WeakKeyDictionary.__setitem__方法代码示例

# 需要导入模块: from weakref import WeakKeyDictionary [as 别名]
# 或者: from weakref.WeakKeyDictionary import __setitem__ [as 别名]
class CallbackProperty(object):
    """
    A property that callback functions can be added to.

    When a callback property changes value, each callback function
    is called with information about the state change. Otherwise,
    callback properties behave just like normal instance variables.

    CallbackProperties must be defined at the class level. Use
    the helper function :func:`~echo.add_callback` to attach a callback to
    a specific instance of a class with CallbackProperties

    Parameters
    ----------
    default
        The initial value for the property
    docstring : str
        The docstring for the property
    getter, setter : func
        Custom getter and setter functions (advanced)
    """

    def __init__(self, default=None, docstring=None, getter=None, setter=None):
        """
        :param default: The initial value for the property
        """
        self._default = default
        self._callbacks = WeakKeyDictionary()
        self._2arg_callbacks = WeakKeyDictionary()
        self._disabled = WeakKeyDictionary()
        self._values = WeakKeyDictionary()

        if getter is None:
            getter = self._default_getter

        if setter is None:
            setter = self._default_setter

        self._getter = getter
        self._setter = setter

        if docstring is not None:
            self.__doc__ = docstring

    def _default_getter(self, instance, owner=None):
        return self._values.get(instance, self._default)

    def _default_setter(self, instance, value):
        self._values.__setitem__(instance, value)

    def __get__(self, instance, owner=None):
        if instance is None:
            return self
        return self._getter(instance)

    def __set__(self, instance, value):
        try:
            old = self.__get__(instance)
        except AttributeError:  # pragma: no cover
            old = None
        self._setter(instance, value)
        new = self.__get__(instance)
        if old != new:
            self.notify(instance, old, new)

    def setter(self, func):
        """
        Method to use as a decorator, to mimic @property.setter
        """
        self._setter = func
        return self

    def _get_full_info(self, instance):

        # Some callback subclasses may contain additional info in addition
        # to the main value, and we need to use this full information when
        # comparing old and new 'values', so this method is used in that
        # case. The result should be a tuple where the first item is the
        # actual primary value of the property and the second item is any
        # additional data to use in the comparison.

        # Note that we need to make sure we convert any list here to a tuple
        # to make sure the value is immutable, otherwise comparisons of
        # old != new will not show any difference (since the list can still)
        # be modified in-place

        value = self.__get__(instance)
        if isinstance(value, list):
            value = tuple(value)
        return value, None

    def notify(self, instance, old, new):
        """
        Call all callback functions with the current value

        Each callback will either be called using
        callback(new) or callback(old, new) depending
        on whether ``echo_old`` was set to `True` when calling
        :func:`~echo.add_callback`

#.........这里部分代码省略.........

# 需要导入模块: from weakref import WeakKeyDictionary [as 别名]
# 或者: from weakref.WeakKeyDictionary import __setitem__ [as 别名]
class CallbackProperty(object):

    """A property that callback functions can be added to.

    When a callback property changes value, each callback function
    is called with information about the state change. Otherwise,
    callback properties behave just like normal instance variables.

    CallbackProperties must be defined at the class level. Use
    the helper function :func:`add_callback` to attach a callback to
    a specific instance of a class with CallbackProperties
    """

    def __init__(self, default=None, getter=None, setter=None, docstring=None):
        """
        :param default: The initial value for the property
        """
        self._default = default
        self._callbacks = WeakKeyDictionary()
        self._2arg_callbacks = WeakKeyDictionary()
        self._disabled = WeakKeyDictionary()
        self._values = WeakKeyDictionary()

        if getter is None:
            getter = self._default_getter

        if setter is None:
            setter = self._default_setter

        self._getter = getter
        self._setter = setter

        if docstring is not None:
            self.__doc__ = docstring

    def _default_getter(self, instance, owner=None):
        return self._values.get(instance, self._default)

    def _default_setter(self, instance, value):
        self._values.__setitem__(instance, value)

    def __get__(self, instance, owner=None):
        if instance is None:
            return self
        return self._getter(instance)

    def __set__(self, instance, value):
        try:
            old = self.__get__(instance)
        except AttributeError:
            old = None
        self._setter(instance, value)
        new = self.__get__(instance)
        if old != new:
            self.notify(instance, old, new)

    def setter(self, func):
        """
        Method to use as a decorator, to mimic @property.setter
        """
        self._setter = func
        return self

    def notify(self, instance, old, new):
        """Call all callback functions with the current value

        :param instance: The instance to consider
        :param old: The old value of the property
        :param new: The new value of the property

        Each callback will either be called using
        callback(new) or callback(old, new) depending
        on whether echo_old was True during add_callback
        """
        if self._disabled.get(instance, False):
            return
        for cback in self._callbacks.get(instance, []):
            cback(new)
        for cback in self._2arg_callbacks.get(instance, []):
            cback(old, new)

    def disable(self, instance):
        """Disable callbacks for a specific instance"""
        self._disabled[instance] = True

    def enable(self, instance):
        """Enable previously-disabled callbacks for a specific instance"""
        self._disabled[instance] = False

    def add_callback(self, instance, func, echo_old=False):
        """Add a callback to a specific instance that manages this property

        :param instance: Instance to bind the callback to
        :param func: Callback function
        :param echo_old: If true, the callback function will be invoked
        with both the old and new values of the property, as func(old, new)
        If False (the default), will be invoked as func(new)
        """
        if echo_old:
            self._2arg_callbacks.setdefault(instance, []).append(func)
#.........这里部分代码省略.........

# 需要导入模块: from weakref import WeakKeyDictionary [as 别名]
# 或者: from weakref.WeakKeyDictionary import __setitem__ [as 别名]
 def __setitem__(self, key, value):
     #og_v = self.data.get(ref(key),not value)
     WeakKeyDictionary.__setitem__(self, key, value)
     #if og_v is not value:
     self.doCallbacks('__setitem__', key, value)