def disconnect(receiver, signal=Any, sender=Any, weak=True): """Disconnect receiver from sender for signal receiver -- the registered receiver to disconnect signal -- the registered signal to disconnect sender -- the registered sender to disconnect weak -- the weakref state to disconnect disconnect reverses the process of connect, the semantics for the individual elements are logically equivalent to a tuple of (receiver, signal, sender, weak) used as a key to be deleted from the internal routing tables. (The actual process is slightly more complex but the semantics are basically the same). Note: Using disconnect is not required to cleanup routing when an object is deleted, the framework will remove routes for deleted objects automatically. It's only necessary to disconnect if you want to stop routing to a live object. returns None, may raise DispatcherTypeError or DispatcherKeyError """ if signal is None: raise errors.DispatcherTypeError( 'Signal cannot be None (receiver=%r sender=%r)'%( receiver,sender) ) if weak: receiver = saferef.safeRef(receiver) senderkey = id(sender) try: signals = connections[senderkey] receivers = signals[signal] except KeyError: raise errors.DispatcherKeyError( """No receivers found for signal %r from sender %r""" %( signal, sender ) ) try: # also removes from receivers _removeOldBackRefs(senderkey, signal, receiver, receivers) except ValueError: raise errors.DispatcherKeyError( """No connection to receiver %s for signal %s from sender %s""" %( receiver, signal, sender ) ) _cleanupConnections(senderkey, signal)
def connect(receiver, signal=Any, sender=Any, weak=True):
"""Connect receiver to sender for signal
receiver -- a callable Python object which is to receive
messages/signals/events. Receivers must be hashable
objects.
if weak is True, then receiver must be weak-referencable
(more precisely saferef.safeRef() must be able to create
a reference to the receiver).
Receivers are fairly flexible in their specification,
as the machinery in the robustApply module takes care
of most of the details regarding figuring out appropriate
subsets of the sent arguments to apply to a given
receiver.
Note:
if receiver is itself a weak reference (a callable),
it will be de-referenced by the system's machinery,
so *generally* weak references are not suitable as
receivers, though some use might be found for the
facility whereby a higher-level library passes in
pre-weakrefed receiver references.
signal -- the signal to which the receiver should respond
if Any, receiver will receive any signal from the
indicated sender (which might also be Any, but is not
necessarily Any).
Otherwise must be a hashable Python object other than
None (DispatcherError raised on None).
sender -- the sender to which the receiver should respond
if Any, receiver will receive the indicated signals
from any sender.
if Anonymous, receiver will only receive indicated
signals from send/sendExact which do not specify a
sender, or specify Anonymous explicitly as the sender.
Otherwise can be any python object.
weak -- whether to use weak references to the receiver
By default, the module will attempt to use weak
references to the receiver objects. If this parameter
is false, then strong references will be used.
returns None, may raise DispatcherTypeError
"""
if signal is None:
raise errors.DispatcherTypeError(
'Signal cannot be None (receiver=%r sender=%r)'%( receiver,sender)
)
if weak:
receiver = saferef.safeRef(receiver, onDelete=_removeReceiver)
senderkey = id(sender)
if connections.has_key(senderkey):
signals = connections[senderkey]
else:
connections[senderkey] = signals = {}
# Keep track of senders for cleanup.
# Is Anonymous something we want to clean up?
if sender not in (None, Anonymous, Any):
def remove(object, senderkey=senderkey):
_removeSender(senderkey=senderkey)
# Skip objects that can not be weakly referenced, which means
# they won't be automatically cleaned up, but that's too bad.
try:
weakSender = weakref.ref(sender, remove)
senders[senderkey] = weakSender
except:
pass
receiverID = id(receiver)
# get current set, remove any current references to
# this receiver in the set, including back-references
if signals.has_key(signal):
receivers = signals[signal]
_removeOldBackRefs(senderkey, signal, receiver, receivers)
else:
receivers = signals[signal] = []
try:
current = sendersBack.get( receiverID )
if current is None:
sendersBack[ receiverID ] = current = []
if senderkey not in current:
current.append(senderkey)
except:
pass
receivers.append(receiver)