def connect(self, receiver, sender=ANY, weak=True):
"""Connect *receiver* to signal events sent by *sender*.
:param receiver: A callable. Will be invoked by :meth:`send` with
`sender=` as a single positional argument and any \*\*kwargs that
were provided to a call to :meth:`send`.
:param sender: Any object or :obj:`ANY`, defaults to ``ANY``.
Restricts notifications delivered to *receiver* to only those
:meth:`send` emissions sent by *sender*. If ``ANY``, the receiver
will always be notified. A *receiver* may be connected to
multiple *sender* values on the same Signal through multiple calls
to :meth:`connect`.
:param weak: If true, the Signal will hold a weakref to *receiver*
and automatically disconnect when *receiver* goes out of scope or
is garbage collected. Defaults to True.
"""
receiver_id = hashable_identity(receiver)
if weak:
receiver_ref = reference(receiver, self._cleanup_receiver)
receiver_ref.receiver_id = receiver_id
else:
receiver_ref = receiver
if sender is ANY:
sender_id = ANY_ID
else:
sender_id = hashable_identity(sender)
self.receivers.setdefault(receiver_id, receiver_ref)
self._by_sender[sender_id].add(receiver_id)
self._by_receiver[receiver_id].add(sender_id)
del receiver_ref
if sender is not ANY and sender_id not in self._weak_senders:
# wire together a cleanup for weakref-able senders
try:
sender_ref = reference(sender, self._cleanup_sender)
sender_ref.sender_id = sender_id
except TypeError:
pass
else:
self._weak_senders.setdefault(sender_id, sender_ref)
del sender_ref
# broadcast this connection. if receivers raise, disconnect.
if receiver_connected.receivers and self is not receiver_connected:
try:
receiver_connected.send(self,
receiver_arg=receiver,
sender_arg=sender,
weak_arg=weak)
except:
self.disconnect(receiver, sender)
raise
return receiver
def connect(self, receiver, sender=ANY, weak=True):
"""Connect *receiver* to signal events sent by *sender*.
:param receiver: A callable. Will be invoked by :meth:`send` with
`sender=` as a single positional argument and any \*\*kwargs that
were provided to a call to :meth:`send`.
:param sender: Any object or :obj:`ANY`, defaults to ``ANY``.
Restricts notifications delivered to *receiver* to only those
:meth:`send` emissions sent by *sender*. If ``ANY``, the receiver
will always be notified. A *receiver* may be connected to
multiple *sender* values on the same Signal through multiple calls
to :meth:`connect`.
:param weak: If true, the Signal will hold a weakref to *receiver*
and automatically disconnect when *receiver* goes out of scope or
is garbage collected. Defaults to True.
"""
receiver_id = hashable_identity(receiver)
if weak:
receiver_ref = reference(receiver, self._cleanup_receiver)
receiver_ref.receiver_id = receiver_id
else:
receiver_ref = receiver
if sender is ANY:
sender_id = ANY_ID
else:
sender_id = hashable_identity(sender)
self.receivers.setdefault(receiver_id, receiver_ref)
self._by_sender[sender_id].add(receiver_id)
self._by_receiver[receiver_id].add(sender_id)
del receiver_ref
if sender is not ANY and sender_id not in self._weak_senders:
# wire together a cleanup for weakref-able senders
try:
sender_ref = reference(sender, self._cleanup_sender)
sender_ref.sender_id = sender_id
except TypeError:
pass
else:
self._weak_senders.setdefault(sender_id, sender_ref)
del sender_ref
# broadcast this connection. if receivers raise, disconnect.
if receiver_connected.receivers and self is not receiver_connected:
try:
receiver_connected.send(self,
receiver_arg=receiver,
sender_arg=sender,
weak_arg=weak)
except:
self.disconnect(receiver, sender)
raise
return receiver
def connect(self, receiver, weak=True): """\ Connect a signal receiver to me. `proc` will be called with two positional arguments: the destination object and the signal that's transmitted. Whatever keywords args the sender set in its .send() call are passed as-is. """ if not hasattr(self,'_receivers'): self._receivers = dict() receiver_id = hashable_identity(receiver) if weak: receiver_ref = reference(receiver, self._cleanup_receiver) receiver_ref.receiver_id = receiver_id else: receiver_ref = receiver self._receivers.setdefault(receiver_id, receiver_ref)
def connect(self, receiver, sender=ANY, weak=True):
"""Connect *receiver* to signal events send by *sender*.
:param receiver: A callable. Will be invoked by :meth:`send`. Will
be invoked with `sender=` as a named argument and any \*\*kwargs
that were provided to a call to :meth:`send`.
:param sender: Any object or :attr:`Signal.ANY`. Restricts
notifications to *receiver* to only those :meth:`send` emissions
sent by *sender*. If ``ANY``, the receiver will always be
notified. A *receiver* may be connected to multiple *sender* on
the same Signal. Defaults to ``ANY``.
:param weak: If true, the Signal will hold a weakref to *receiver*
and automatically disconnect when *receiver* goes out of scope or
is garbage collected. Defaults to True.
"""
receiver_id = hashable_identity(receiver)
if weak:
receiver_ref = reference(receiver, self._cleanup_receiver)
receiver_ref.receiver_id = receiver_id
else:
receiver_ref = receiver
if sender is ANY:
sender_id = ANY_ID
else:
sender_id = hashable_identity(sender)
# 主要需要登记 receiver_id, sender_id， receiver_ref
# receiver_ref 对应两种情况 1. 当要求存入弱引用时(选项weak 为 true，需要对传入的引用做一次弱引用的封装)
# 2. 选项为false时，直接赋值为原值就好了
# receiver的引用保存在 receivers dict 中，通过receiver_id进行查询
self.receivers.setdefault(receiver_id, receiver_ref)
# _by_sender 字典用来保存对应于每个sender的receiver 订阅者
# _by_receiver 字典相反，用来保存对于每个 receiver 订阅者的 sender
self._by_sender[sender_id].add(receiver_id)
self._by_receiver[receiver_id].add(sender_id)
# todo 这个del 很奇怪，每次函数结束receiver_ref是会被自动删除的才对，为什么要自行del
del receiver_ref
if sender is not ANY and sender_id not in self._weak_senders:
# wire together a cleanup for weakref-able senders
try:
sender_ref = reference(sender, self._cleanup_sender)
sender_ref.sender_id = sender_id
except TypeError:
pass
# 第一次碰到 try-except中的else。这个else对应于 没有exception抛出的情况 要执行的内容
else:
self._weak_senders.setdefault(sender_id, sender_ref)
del sender_ref
# broadcast this connection. if receivers raise, disconnect.
# todo receiver_connected 的作用？
# 每次对任意一个Signal（当然receriver_connected Signal除外）,
# 都会触发receiver_connected信号，我们可以对receiver_connected 信号进行订阅，做一些有用的事情，比如记录每次信号触发的信息
if receiver_connected.receivers and self is not receiver_connected:
# 判断 self is not receiver_connected 十分重要，不然会引起死循环
try:
receiver_connected.send(
self, # sender 是Signal自己
receiver_arg=
receiver, # 下面的args 是记录的信号收发的信息，三要素：收信人，寄信人，是否要求弱引用
sender_arg=sender,
weak_arg=weak)
except:
self.disconnect(receiver, sender)
raise
return receiver
