Python weakref 模块，ReferenceType() 实例源码

def list_pubs():
#    import pdb; pdb.set_trace()
    import weakref
    msg = []
    for receiver in signals.post_save.receivers:
        (receiver_class_name,_), receiver = receiver
        # django.contrib.contenttypes.generic.GenericForeignKey.instance_pre_init is not weakref
        if isinstance(receiver, weakref.ReferenceType):
            receiver = receiver()
        receiver = getattr(receiver, '__wraps__', receiver)
        receiver_name = getattr(receiver, '__name__', str(receiver))
        text = "%s.%s" % (receiver_class_name, receiver_name)
        if receiver_name == 'publish_rdf' :
            msg.append(text)

    return str(msg)

def emit(self, *args, **kwargs):
        '''
        Emit the event with the given positional and keyword arguments.

        Returns a dict mapping event listeners to their results, or an exception
        instance if calling the listener raised one.
        '''
        results = {}
        # kwargs['__event__'] = self
        for listener in self._listeners.values():
            if isinstance(listener, (weakref.ReferenceType, BoundMethodWeakref)):
                listener = listener()
                if listener is None:
                    # This shouldn't happen, but we need to guard for it.
                    continue
            try:
                results[listener] = listener(*args, **kwargs)
            except Exception as e:
                if self._abort_on_error:
                    raise
                results[listener] = e
                print("error in listener: %s".format(listener))
                import traceback
                traceback.print_exc()
        return results

def _clear_dead_receivers(self):
        if self._dead_receivers:
            self._dead_receivers = False
            new_receivers = []
            for rec in self.receivers:
                if isinstance(rec[1], weakref.ReferenceType) and rec[1]() is None:
                    continue
                new_receivers.append(rec)
            self.receivers = new_receivers

def _clear_dead_receivers(self):
        # Note: caller is assumed to hold self.lock.
        if self._dead_receivers:
            self._dead_receivers = False
            new_receivers = []
            for r in self.receivers:
                if isinstance(r[1], weakref.ReferenceType) and r[1]() is None:
                    continue
                new_receivers.append(r)
            self.receivers = new_receivers

def _live_receivers(self, sender):
        """
        Filter sequence of receivers to get resolved, live receivers.

        This checks for weak references and resolves them, then returning only
        live receivers.
        """
        receivers = None
        if self.use_caching and not self._dead_receivers:
            receivers = self.sender_receivers_cache.get(sender)
            # We could end up here with NO_RECEIVERS even if we do check this case in
            # .send() prior to calling _live_receivers() due to concurrent .send() call.
            if receivers is NO_RECEIVERS:
                return []
        if receivers is None:
            with self.lock:
                self._clear_dead_receivers()
                senderkey = _make_id(sender)
                receivers = []
                for (receiverkey, r_senderkey), receiver in self.receivers:
                    if r_senderkey == NONE_ID or r_senderkey == senderkey:
                        receivers.append(receiver)
                if self.use_caching:
                    if not receivers:
                        self.sender_receivers_cache[sender] = NO_RECEIVERS
                    else:
                        # Note, we must cache the weakref versions.
                        self.sender_receivers_cache[sender] = receivers
        non_weak_receivers = []
        for receiver in receivers:
            if isinstance(receiver, weakref.ReferenceType):
                # Dereference the weak reference.
                receiver = receiver()
                if receiver is not None:
                    non_weak_receivers.append(receiver)
            else:
                non_weak_receivers.append(receiver)
        return non_weak_receivers

def __init__(self, sw):
        '''Constructor, May be extended, do not override.
            sw -- soapWriter instance
        '''
        self.sw = None
        if not isinstance(sw, weakref.ReferenceType) and sw is not None:
            self.sw = weakref.ref(sw)
        else:
            self.sw = sw

def __init__(self, sw):
        '''Constructor, May be extended, do not override.
            sw -- soapWriter instance
        '''
        self.sw = None
        if type(sw) != weakref.ReferenceType and sw is not None:
            self.sw = weakref.ref(sw)
        else:
            self.sw = sw

def __init__(self, sw):
        '''Constructor, May be extended, do not override.
            sw -- soapWriter instance
        '''
        self.sw = None
        if type(sw) != weakref.ReferenceType and sw is not None:
            self.sw = weakref.ref(sw)
        else:
            self.sw = sw

def removeListener(self, listener, exclude='dummy'):
        """
        Remove a listener object or callback.
        :listener: can be object, weakref, sequence or '*'
        """

        if listener == '*':
            self.warning('Removing all listeners')
            listener = [k for k in self.listeners.keys() if not k().name==exclude]

        elif isString(listener):
            listener = [k for k in self.listeners.keys() if k().name==listener]

        if isSequence(listener):
            while listener:
              self.removeListener(listener.pop())
            return

        elif not isinstance(listener,weakref.ReferenceType):
            listener = weakref.ref(listener,self._listenerDied)

        try:
            self.listeners.pop(listener)
        except Exception, e:
            return False
        if not self.listeners:
            self.unsubscribeEvents()
        return True

def _clear_dead_receivers(self):
        # Note: caller is assumed to hold self.lock.
        if self._dead_receivers:
            self._dead_receivers = False
            new_receivers = []
            for r in self.receivers:
                if isinstance(r[1], weakref.ReferenceType) and r[1]() is None:
                    continue
                new_receivers.append(r)
            self.receivers = new_receivers

def _live_receivers(self, sender):
        """
        Filter sequence of receivers to get resolved, live receivers.

        This checks for weak references and resolves them, then returning only
        live receivers.
        """
        receivers = None
        if self.use_caching and not self._dead_receivers:
            receivers = self.sender_receivers_cache.get(sender)
            # We could end up here with NO_RECEIVERS even if we do check this case in
            # .send() prior to calling _live_receivers() due to concurrent .send() call.
            if receivers is NO_RECEIVERS:
                return []
        if receivers is None:
            with self.lock:
                self._clear_dead_receivers()
                senderkey = _make_id(sender)
                receivers = []
                for (receiverkey, r_senderkey), receiver in self.receivers:
                    if r_senderkey == NONE_ID or r_senderkey == senderkey:
                        receivers.append(receiver)
                if self.use_caching:
                    if not receivers:
                        self.sender_receivers_cache[sender] = NO_RECEIVERS
                    else:
                        # Note, we must cache the weakref versions.
                        self.sender_receivers_cache[sender] = receivers
        non_weak_receivers = []
        for receiver in receivers:
            if isinstance(receiver, weakref.ReferenceType):
                # Dereference the weak reference.
                receiver = receiver()
                if receiver is not None:
                    non_weak_receivers.append(receiver)
            else:
                non_weak_receivers.append(receiver)
        return non_weak_receivers

def __init__(self, sw):
        '''Constructor, May be extended, do not override.
            sw -- soapWriter instance
        '''
        self.sw = None
        if type(sw) != weakref.ReferenceType and sw is not None:
            self.sw = weakref.ref(sw)
        else:
            self.sw = sw

def _clear_dead_receivers(self):
        # Note: caller is assumed to hold self.lock.
        if self._dead_receivers:
            self._dead_receivers = False
            new_receivers = []
            for r in self.receivers:
                if isinstance(r[1], weakref.ReferenceType) and r[1]() is None:
                    continue
                new_receivers.append(r)
            self.receivers = new_receivers

def _live_receivers(self, sender):
        """
        Filter sequence of receivers to get resolved, live receivers.

        This checks for weak references and resolves them, then returning only
        live receivers.
        """
        receivers = None
        if self.use_caching and not self._dead_receivers:
            receivers = self.sender_receivers_cache.get(sender)
            # We could end up here with NO_RECEIVERS even if we do check this case in
            # .send() prior to calling _live_receivers() due to concurrent .send() call.
            if receivers is NO_RECEIVERS:
                return []
        if receivers is None:
            with self.lock:
                self._clear_dead_receivers()
                senderkey = _make_id(sender)
                receivers = []
                for (receiverkey, r_senderkey), receiver in self.receivers:
                    if r_senderkey == NONE_ID or r_senderkey == senderkey:
                        receivers.append(receiver)
                if self.use_caching:
                    if not receivers:
                        self.sender_receivers_cache[sender] = NO_RECEIVERS
                    else:
                        # Note, we must cache the weakref versions.
                        self.sender_receivers_cache[sender] = receivers
        non_weak_receivers = []
        for receiver in receivers:
            if isinstance(receiver, weakref.ReferenceType):
                # Dereference the weak reference.
                receiver = receiver()
                if receiver is not None:
                    non_weak_receivers.append(receiver)
            else:
                non_weak_receivers.append(receiver)
        return non_weak_receivers

def _clear_dead_receivers(self):
        # Note: caller is assumed to hold self.lock.
        if self._dead_receivers:
            self._dead_receivers = False
            new_receivers = []
            for r in self.receivers:
                if isinstance(r[1], weakref.ReferenceType) and r[1]() is None:
                    continue
                new_receivers.append(r)
            self.receivers = new_receivers

def _live_receivers(self, sender):
        """
        Filter sequence of receivers to get resolved, live receivers.

        This checks for weak references and resolves them, then returning only
        live receivers.
        """
        receivers = None
        if self.use_caching and not self._dead_receivers:
            receivers = self.sender_receivers_cache.get(sender)
            # We could end up here with NO_RECEIVERS even if we do check this case in
            # .send() prior to calling _live_receivers() due to concurrent .send() call.
            if receivers is NO_RECEIVERS:
                return []
        if receivers is None:
            with self.lock:
                self._clear_dead_receivers()
                senderkey = _make_id(sender)
                receivers = []
                for (receiverkey, r_senderkey), receiver in self.receivers:
                    if r_senderkey == NONE_ID or r_senderkey == senderkey:
                        receivers.append(receiver)
                if self.use_caching:
                    if not receivers:
                        self.sender_receivers_cache[sender] = NO_RECEIVERS
                    else:
                        # Note, we must cache the weakref versions.
                        self.sender_receivers_cache[sender] = receivers
        non_weak_receivers = []
        for receiver in receivers:
            if isinstance(receiver, weakref.ReferenceType):
                # Dereference the weak reference.
                receiver = receiver()
                if receiver is not None:
                    non_weak_receivers.append(receiver)
            else:
                non_weak_receivers.append(receiver)
        return non_weak_receivers

def __init__(self, sw):
        '''Constructor, May be extended, do not override.
            sw -- soapWriter instance
        '''
        self.sw = None
        if type(sw) != weakref.ReferenceType and sw is not None:
            self.sw = weakref.ref(sw)
        else:
            self.sw = sw

def __init__(self, sw):
        '''Constructor, May be extended, do not override.
            sw -- soapWriter instance
        '''
        self.sw = None
        if type(sw) != weakref.ReferenceType and sw is not None:
            self.sw = weakref.ref(sw)
        else:
            self.sw = sw

def _clear_dead_receivers(self):
        # Note: caller is assumed to hold self.lock.
        if self._dead_receivers:
            self._dead_receivers = False
            new_receivers = []
            for r in self.receivers:
                if isinstance(r[1], weakref.ReferenceType) and r[1]() is None:
                    continue
                new_receivers.append(r)
            self.receivers = new_receivers

def _live_receivers(self, sender):
        """
        Filter sequence of receivers to get resolved, live receivers.

        This checks for weak references and resolves them, then returning only
        live receivers.
        """
        receivers = None
        if self.use_caching and not self._dead_receivers:
            receivers = self.sender_receivers_cache.get(sender)
            # We could end up here with NO_RECEIVERS even if we do check this case in
            # .send() prior to calling _live_receivers() due to concurrent .send() call.
            if receivers is NO_RECEIVERS:
                return []
        if receivers is None:
            with self.lock:
                self._clear_dead_receivers()
                senderkey = _make_id(sender)
                receivers = []
                for (receiverkey, r_senderkey), receiver in self.receivers:
                    if r_senderkey == NONE_ID or r_senderkey == senderkey:
                        receivers.append(receiver)
                if self.use_caching:
                    if not receivers:
                        self.sender_receivers_cache[sender] = NO_RECEIVERS
                    else:
                        # Note, we must cache the weakref versions.
                        self.sender_receivers_cache[sender] = receivers
        non_weak_receivers = []
        for receiver in receivers:
            if isinstance(receiver, weakref.ReferenceType):
                # Dereference the weak reference.
                receiver = receiver()
                if receiver is not None:
                    non_weak_receivers.append(receiver)
            else:
                non_weak_receivers.append(receiver)
        return non_weak_receivers

def __init__(self, sw):
        '''Constructor, May be extended, do not override.
            sw -- soapWriter instance
        '''
        self.sw = None
        if type(sw) != weakref.ReferenceType and sw is not None:
            self.sw = weakref.ref(sw)
        else:
            self.sw = sw

def reconnect_signals(self):
        """
            Reconnect the signals
        """
        for signal, receivers in self.signal_map.items():
            for sender_id, receiver in receivers:
                lookup_key, receiver_method = receiver
                if isinstance(receiver_method, weakref.ReferenceType):
                    receiver_method = receiver_method()

                signal.connect(
                    receiver_method,
                    sender=self.senders[sender_id],
                    dispatch_uid=lookup_key[0])

def test_alive(self):
        o = Object(1)
        r = weakref.WeakMethod(o.some_method)
        self.assertIsInstance(r, weakref.ReferenceType)
        self.assertIsInstance(r(), type(o.some_method))
        self.assertIs(r().__self__, o)
        self.assertIs(r().__func__, o.some_method.__func__)
        self.assertEqual(r()(), 4)

def _clear_dead_receivers(self):
        # Note: caller is assumed to hold self.lock.
        if self._dead_receivers:
            self._dead_receivers = False
            new_receivers = []
            for r in self.receivers:
                if isinstance(r[1], weakref.ReferenceType) and r[1]() is None:
                    continue
                new_receivers.append(r)
            self.receivers = new_receivers

def _live_receivers(self, sender):
        """
        Filter sequence of receivers to get resolved, live receivers.

        This checks for weak references and resolves them, then returning only
        live receivers.
        """
        receivers = None
        if self.use_caching and not self._dead_receivers:
            receivers = self.sender_receivers_cache.get(sender)
            # We could end up here with NO_RECEIVERS even if we do check this case in
            # .send() prior to calling _live_receivers() due to concurrent .send() call.
            if receivers is NO_RECEIVERS:
                return []
        if receivers is None:
            with self.lock:
                self._clear_dead_receivers()
                senderkey = _make_id(sender)
                receivers = []
                for (receiverkey, r_senderkey), receiver in self.receivers:
                    if r_senderkey == NONE_ID or r_senderkey == senderkey:
                        receivers.append(receiver)
                if self.use_caching:
                    if not receivers:
                        self.sender_receivers_cache[sender] = NO_RECEIVERS
                    else:
                        # Note, we must cache the weakref versions.
                        self.sender_receivers_cache[sender] = receivers
        non_weak_receivers = []
        for receiver in receivers:
            if isinstance(receiver, weakref.ReferenceType):
                # Dereference the weak reference.
                receiver = receiver()
                if receiver is not None:
                    non_weak_receivers.append(receiver)
            else:
                non_weak_receivers.append(receiver)
        return non_weak_receivers

def _clear_dead_receivers(self):
        # Note: caller is assumed to hold self.lock.
        if self._dead_receivers:
            self._dead_receivers = False
            new_receivers = []
            for r in self.receivers:
                if isinstance(r[1], weakref.ReferenceType) and r[1]() is None:
                    continue
                new_receivers.append(r)
            self.receivers = new_receivers

def _live_receivers(self, sender):
        """
        Filter sequence of receivers to get resolved, live receivers.

        This checks for weak references and resolves them, then returning only
        live receivers.
        """
        receivers = None
        if self.use_caching and not self._dead_receivers:
            receivers = self.sender_receivers_cache.get(sender)
            # We could end up here with NO_RECEIVERS even if we do check this case in
            # .send() prior to calling _live_receivers() due to concurrent .send() call.
            if receivers is NO_RECEIVERS:
                return []
        if receivers is None:
            with self.lock:
                self._clear_dead_receivers()
                senderkey = _make_id(sender)
                receivers = []
                for (receiverkey, r_senderkey), receiver in self.receivers:
                    if r_senderkey == NONE_ID or r_senderkey == senderkey:
                        receivers.append(receiver)
                if self.use_caching:
                    if not receivers:
                        self.sender_receivers_cache[sender] = NO_RECEIVERS
                    else:
                        # Note, we must cache the weakref versions.
                        self.sender_receivers_cache[sender] = receivers
        non_weak_receivers = []
        for receiver in receivers:
            if isinstance(receiver, weakref.ReferenceType):
                # Dereference the weak reference.
                receiver = receiver()
                if receiver is not None:
                    non_weak_receivers.append(receiver)
            else:
                non_weak_receivers.append(receiver)
        return non_weak_receivers

def _call_callback(self, callback, user_arg, user_args, emit_args):
        if user_args:
            args_to_pass = []
            for arg in user_args:
                if isinstance(arg, weakref.ReferenceType):
                    arg = arg()
                    if arg is None:
                        # If the weakref is None, the referenced object
                        # was cleaned up. We just skip the entire
                        # callback in this case. The weakref cleanup
                        # handler will have removed the callback when
                        # this happens, so no need to actually remove
                        # the callback here.
                        return False
                args_to_pass.append(arg)

            args_to_pass.extend(emit_args)
        else:
            # Optimization: Don't create a new list when there are
            # no user_args
            args_to_pass = emit_args

        # The deprecated user_arg argument was added to the end
        # instead of the beginning.
        if user_arg is not None:
            args_to_pass = itertools.chain(args_to_pass, (user_arg,))

        return bool(callback(*args_to_pass))

def test_alive(self):
        o = Object(1)
        r = weakref.WeakMethod(o.some_method)
        self.assertIsInstance(r, weakref.ReferenceType)
        self.assertIsInstance(r(), type(o.some_method))
        self.assertIs(r().__self__, o)
        self.assertIs(r().__func__, o.some_method.__func__)
        self.assertEqual(r()(), 4)

def _clear_dead_receivers(self):
        # Note: caller is assumed to hold self.lock.
        if self._dead_receivers:
            self._dead_receivers = False
            new_receivers = []
            for r in self.receivers:
                if isinstance(r[1], weakref.ReferenceType) and r[1]() is None:
                    continue
                new_receivers.append(r)
            self.receivers = new_receivers

def _live_receivers(self, sender):
        """
        Filter sequence of receivers to get resolved, live receivers.

        This checks for weak references and resolves them, then returning only
        live receivers.
        """
        receivers = None
        if self.use_caching and not self._dead_receivers:
            receivers = self.sender_receivers_cache.get(sender)
            # We could end up here with NO_RECEIVERS even if we do check this case in
            # .send() prior to calling _live_receivers() due to concurrent .send() call.
            if receivers is NO_RECEIVERS:
                return []
        if receivers is None:
            with self.lock:
                self._clear_dead_receivers()
                senderkey = _make_id(sender)
                receivers = []
                for (receiverkey, r_senderkey), receiver in self.receivers:
                    if r_senderkey == NONE_ID or r_senderkey == senderkey:
                        receivers.append(receiver)
                if self.use_caching:
                    if not receivers:
                        self.sender_receivers_cache[sender] = NO_RECEIVERS
                    else:
                        # Note, we must cache the weakref versions.
                        self.sender_receivers_cache[sender] = receivers
        non_weak_receivers = []
        for receiver in receivers:
            if isinstance(receiver, weakref.ReferenceType):
                # Dereference the weak reference.
                receiver = receiver()
                if receiver is not None:
                    non_weak_receivers.append(receiver)
            else:
                non_weak_receivers.append(receiver)
        return non_weak_receivers

def _clear_dead_receivers(self):
        # Note: caller is assumed to hold self.lock.
        if self._dead_receivers:
            self._dead_receivers = False
            new_receivers = []
            for r in self.receivers:
                if isinstance(r[1], weakref.ReferenceType) and r[1]() is None:
                    continue
                new_receivers.append(r)
            self.receivers = new_receivers

def _live_receivers(self, sender):
        """
        Filter sequence of receivers to get resolved, live receivers.

        This checks for weak references and resolves them, then returning only
        live receivers.
        """
        receivers = None
        if self.use_caching and not self._dead_receivers:
            receivers = self.sender_receivers_cache.get(sender)
            # We could end up here with NO_RECEIVERS even if we do check this case in
            # .send() prior to calling _live_receivers() due to concurrent .send() call.
            if receivers is NO_RECEIVERS:
                return []
        if receivers is None:
            with self.lock:
                self._clear_dead_receivers()
                senderkey = _make_id(sender)
                receivers = []
                for (receiverkey, r_senderkey), receiver in self.receivers:
                    if r_senderkey == NONE_ID or r_senderkey == senderkey:
                        receivers.append(receiver)
                if self.use_caching:
                    if not receivers:
                        self.sender_receivers_cache[sender] = NO_RECEIVERS
                    else:
                        # Note, we must cache the weakref versions.
                        self.sender_receivers_cache[sender] = receivers
        non_weak_receivers = []
        for receiver in receivers:
            if isinstance(receiver, weakref.ReferenceType):
                # Dereference the weak reference.
                receiver = receiver()
                if receiver is not None:
                    non_weak_receivers.append(receiver)
            else:
                non_weak_receivers.append(receiver)
        return non_weak_receivers

def parent(self):
        """The object's parent"""
        if isinstance(self._parent, weakref.ReferenceType):
            return self._parent()
        else:
            return self._parent

def _clear_dead_receivers(self):
        # Note: caller is assumed to hold self.lock.
        if self._dead_receivers:
            self._dead_receivers = False
            new_receivers = []
            for r in self.receivers:
                if isinstance(r[1], weakref.ReferenceType) and r[1]() is None:
                    continue
                new_receivers.append(r)
            self.receivers = new_receivers

def _live_receivers(self, sender):
        """
        Filter sequence of receivers to get resolved, live receivers.

        This checks for weak references and resolves them, then returning only
        live receivers.
        """
        receivers = None
        if self.use_caching and not self._dead_receivers:
            receivers = self.sender_receivers_cache.get(sender)
            # We could end up here with NO_RECEIVERS even if we do check this case in
            # .send() prior to calling _live_receivers() due to concurrent .send() call.
            if receivers is NO_RECEIVERS:
                return []
        if receivers is None:
            with self.lock:
                self._clear_dead_receivers()
                senderkey = _make_id(sender)
                receivers = []
                for (receiverkey, r_senderkey), receiver in self.receivers:
                    if r_senderkey == NONE_ID or r_senderkey == senderkey:
                        receivers.append(receiver)
                if self.use_caching:
                    if not receivers:
                        self.sender_receivers_cache[sender] = NO_RECEIVERS
                    else:
                        # Note, we must cache the weakref versions.
                        self.sender_receivers_cache[sender] = receivers
        non_weak_receivers = []
        for receiver in receivers:
            if isinstance(receiver, weakref.ReferenceType):
                # Dereference the weak reference.
                receiver = receiver()
                if receiver is not None:
                    non_weak_receivers.append(receiver)
            else:
                non_weak_receivers.append(receiver)
        return non_weak_receivers

def _clear_dead_receivers(self):
        # Note: caller is assumed to hold self.lock.
        if self._dead_receivers:
            self._dead_receivers = False
            new_receivers = []
            for r in self.receivers:
                if isinstance(r[1], weakref.ReferenceType) and r[1]() is None:
                    continue
                new_receivers.append(r)
            self.receivers = new_receivers

def _live_receivers(self, sender):
        """
        Filter sequence of receivers to get resolved, live receivers.

        This checks for weak references and resolves them, then returning only
        live receivers.
        """
        receivers = None
        if self.use_caching and not self._dead_receivers:
            receivers = self.sender_receivers_cache.get(sender)
            # We could end up here with NO_RECEIVERS even if we do check this case in
            # .send() prior to calling _live_receivers() due to concurrent .send() call.
            if receivers is NO_RECEIVERS:
                return []
        if receivers is None:
            with self.lock:
                self._clear_dead_receivers()
                senderkey = _make_id(sender)
                receivers = []
                for (receiverkey, r_senderkey), receiver in self.receivers:
                    if r_senderkey == NONE_ID or r_senderkey == senderkey:
                        receivers.append(receiver)
                if self.use_caching:
                    if not receivers:
                        self.sender_receivers_cache[sender] = NO_RECEIVERS
                    else:
                        # Note, we must cache the weakref versions.
                        self.sender_receivers_cache[sender] = receivers
        non_weak_receivers = []
        for receiver in receivers:
            if isinstance(receiver, weakref.ReferenceType):
                # Dereference the weak reference.
                receiver = receiver()
                if receiver is not None:
                    non_weak_receivers.append(receiver)
            else:
                non_weak_receivers.append(receiver)
        return non_weak_receivers

def send(self, source, raw=False, catch_exceptions=False, gather=True):
        """
        Send signal with source.
        If any receiver raises an error, the error propagates back through send,
        terminating the dispatch loop. So it's possible that all receivers
        won't be called if an error is raised.

        :param source: The data to be send to the processor which produces data that will be send to the receivers.
        :param raw: Optional bool parameter to just send the source to the receivers without any processing.
        :param catch_exceptions: Catch and return the exceptions.
        :param gather: Execute multiple receivers at the same time (parallel). On by default!

        :return: Return a list of tuple pairs [(receiver, response), ... ].
        """
        if raw is False:
            try:
                kwargs = await self.process_target(signal=self, source=source)
            except SignalGlueStop:
                # Stop calling the receivers when our glue says we should!
                return []
        else:
            kwargs = dict(**source, signal=self)

        if not self.receivers:
            return []

        # Prepare the responses from the calls.
        responses = []
        gather_list = []
        for key, receiver in self._live_receivers():
            # Dereference the weak reference.
            slf = self.self_refs.get(key, None)
            if slf and isinstance(slf, weakref.ReferenceType):
                slf = slf()
            args = [slf] if slf else []

            # Execute the receiver.
            coro = self.execute_receiver(receiver, args, kwargs, ignore_exceptions=catch_exceptions)
            if gather:
                gather_list.append(coro)
            else:
                responses.append(await coro)

        # If gather, wait on the asyncio.gather operation and return the responses from there.
        if gather:
            return await asyncio.gather(*gather_list)

        # Done, respond with all the results
        return responses

def _live_receivers(self):
        """
        Filter sequence of receivers to get resolved, live receivers.
        This checks for weak references and resolves them, then returning only
        live receivers.
        """
        # We don't use the sender. Set it to none.
        sender = None

        receivers = None
        if self.use_caching and not self._dead_receivers:
            receivers = self.sender_receivers_cache.get(sender)
            # We could end up here with NO_RECEIVERS even if we do check this case in
            # .send() prior to calling _live_receivers() due to concurrent .send() call.
            if receivers is NO_RECEIVERS:
                return []

        if receivers is None:
            with self.lock:
                self._clear_dead_receivers()
                receivers = []
                for receiverkey, receiver in self.receivers:
                    receivers.append((receiverkey, receiver))
                if self.use_caching:
                    if not receivers:
                        self.sender_receivers_cache[sender] = NO_RECEIVERS
                    else:
                        # Note, we must cache the weakref versions.
                        self.sender_receivers_cache[sender] = receivers
        non_weak_receivers = []

        for receiver in receivers:
            key = receiver[0]
            receiver = receiver[1]

            if isinstance(receiver, weakref.ReferenceType):
                # Dereference the weak reference.
                receiver = receiver()
                if receiver is not None:
                    non_weak_receivers.append((key, receiver))
            else:
                non_weak_receivers.append((key, receiver))
        return non_weak_receivers

def objgrep(start, goal, eq=isLike, path='', paths=None, seen=None, showUnknowns=0, maxDepth=None):
    '''An insanely CPU-intensive process for finding stuff.
    '''
    if paths is None:
        paths = []
    if seen is None:
        seen = {}
    if eq(start, goal):
        paths.append(path)
    if seen.has_key(id(start)):
        if seen[id(start)] is start:
            return
    if maxDepth is not None:
        if maxDepth == 0:
            return
        maxDepth -= 1
    seen[id(start)] = start
    if isinstance(start, types.DictionaryType):
        r = []
        for k, v in start.items():
            objgrep(k, goal, eq, path+'{'+repr(v)+'}', paths, seen, showUnknowns, maxDepth)
            objgrep(v, goal, eq, path+'['+repr(k)+']', paths, seen, showUnknowns, maxDepth)
    elif isinstance(start, types.ListType) or isinstance(start, types.TupleType):
        for idx in xrange(len(start)):
            objgrep(start[idx], goal, eq, path+'['+str(idx)+']', paths, seen, showUnknowns, maxDepth)
    elif isinstance(start, types.MethodType):
        objgrep(start.im_self, goal, eq, path+'.im_self', paths, seen, showUnknowns, maxDepth)
        objgrep(start.im_func, goal, eq, path+'.im_func', paths, seen, showUnknowns, maxDepth)
        objgrep(start.im_class, goal, eq, path+'.im_class', paths, seen, showUnknowns, maxDepth)
    elif hasattr(start, '__dict__'):
        for k, v in start.__dict__.items():
            objgrep(v, goal, eq, path+'.'+k, paths, seen, showUnknowns, maxDepth)
        if isinstance(start, types.InstanceType):
            objgrep(start.__class__, goal, eq, path+'.__class__', paths, seen, showUnknowns, maxDepth)
    elif isinstance(start, weakref.ReferenceType):
        objgrep(start(), goal, eq, path+'()', paths, seen, showUnknowns, maxDepth)
    elif (isinstance(start, types.StringTypes+
                    (types.IntType, types.FunctionType,
                     types.BuiltinMethodType, RegexType, types.FloatType,
                     types.NoneType, types.FileType)) or
          type(start).__name__ in ('wrapper_descriptor', 'method_descriptor',
                                   'member_descriptor', 'getset_descriptor')):
        pass
    elif showUnknowns:
        print 'unknown type', type(start), start
    return paths

def enqueue_coro(self, coro, priority=1):

        def future_wrapper(coro, future):
            @functools.wraps(coro)
            async def inner():
                try:
                    res = await coro
                except Exception as e:
                    future.set_exception(e)
                else:
                    future.set_result(res)
                finally:
                    self._process_next.set()
            return inner

        def task_cb(future):
            if isinstance(self._external_cb, weakref.ReferenceType):
                external_cb = self._external_cb()
            else:
                external_cb = self._external_cb

            try:
                res = future.result()

                if self.results_queue.full():
                    self.results_queue.get_nowait()
                asyncio.ensure_future(self.results_queue.put(res), loop=self.loop)

                if external_cb:
                    external_cb(res, None)
            except Exception as e:
                if external_cb:
                    external_cb(None, exc=e)
                else:
                    raise e

        f = asyncio.Future()
        f.add_done_callback(task_cb)

        coro_locals = {key: repr(val) for key, val in coro.cr_frame.f_locals.items()}
        self.tasks_queue.put_nowait(self.Task(future_wrapper(coro, f), priority,
                                              coro_locals, clock()))

def objgrep(start, goal, eq=isLike, path='', paths=None, seen=None, showUnknowns=0, maxDepth=None):
    '''An insanely CPU-intensive process for finding stuff.
    '''
    if paths is None:
        paths = []
    if seen is None:
        seen = {}
    if eq(start, goal):
        paths.append(path)
    if seen.has_key(id(start)):
        if seen[id(start)] is start:
            return
    if maxDepth is not None:
        if maxDepth == 0:
            return
        maxDepth -= 1
    seen[id(start)] = start
    if isinstance(start, types.DictionaryType):
        r = []
        for k, v in start.items():
            objgrep(k, goal, eq, path+'{'+repr(v)+'}', paths, seen, showUnknowns, maxDepth)
            objgrep(v, goal, eq, path+'['+repr(k)+']', paths, seen, showUnknowns, maxDepth)
    elif isinstance(start, types.ListType) or isinstance(start, types.TupleType):
        for idx in xrange(len(start)):
            objgrep(start[idx], goal, eq, path+'['+str(idx)+']', paths, seen, showUnknowns, maxDepth)
    elif isinstance(start, types.MethodType):
        objgrep(start.im_self, goal, eq, path+'.im_self', paths, seen, showUnknowns, maxDepth)
        objgrep(start.im_func, goal, eq, path+'.im_func', paths, seen, showUnknowns, maxDepth)
        objgrep(start.im_class, goal, eq, path+'.im_class', paths, seen, showUnknowns, maxDepth)
    elif hasattr(start, '__dict__'):
        for k, v in start.__dict__.items():
            objgrep(v, goal, eq, path+'.'+k, paths, seen, showUnknowns, maxDepth)
        if isinstance(start, types.InstanceType):
            objgrep(start.__class__, goal, eq, path+'.__class__', paths, seen, showUnknowns, maxDepth)
    elif isinstance(start, weakref.ReferenceType):
        objgrep(start(), goal, eq, path+'()', paths, seen, showUnknowns, maxDepth)
    elif (isinstance(start, types.StringTypes+
                    (types.IntType, types.FunctionType,
                     types.BuiltinMethodType, RegexType, types.FloatType,
                     types.NoneType, types.FileType)) or
          type(start).__name__ in ('wrapper_descriptor', 'method_descriptor',
                                   'member_descriptor', 'getset_descriptor')):
        pass
    elif showUnknowns:
        print 'unknown type', type(start), start
    return paths

def objgrep(start, goal, eq=isLike, path='', paths=None, seen=None,
                showUnknowns=0, maxDepth=None):
        """
        An insanely CPU-intensive process for finding stuff.
        """
        if paths is None:
            paths = []
        if seen is None:
            seen = {}
        if eq(start, goal):
            paths.append(path)
        if id(start) in seen:
            if seen[id(start)] is start:
                return
        if maxDepth is not None:
            if maxDepth == 0:
                return
            maxDepth -= 1
        seen[id(start)] = start
        # Make an alias for those arguments which are passed recursively to
        # objgrep for container objects.
        args = (paths, seen, showUnknowns, maxDepth)
        if isinstance(start, dict):
            for k, v in start.items():
                objgrep(k, goal, eq, path+'{'+repr(v)+'}', *args)
                objgrep(v, goal, eq, path+'['+repr(k)+']', *args)
        elif isinstance(start, (list, tuple, deque)):
            for idx, _elem in enumerate(start):
                objgrep(start[idx], goal, eq, path+'['+str(idx)+']', *args)
        elif isinstance(start, types.MethodType):
            objgrep(start.__self__, goal, eq, path+'.__self__', *args)
            objgrep(start.__func__, goal, eq, path+'.__func__', *args)
            objgrep(start.__self__.__class__, goal, eq,
                    path+'.__self__.__class__', *args)
        elif hasattr(start, '__dict__'):
            for k, v in start.__dict__.items():
                objgrep(v, goal, eq, path+'.'+k, *args)
            if isinstance(start, compat.InstanceType):
                objgrep(start.__class__, goal, eq, path+'.__class__', *args)
        elif isinstance(start, weakref.ReferenceType):
            objgrep(start(), goal, eq, path+'()', *args)
        elif (isinstance(start, (compat.StringType,
                        int, types.FunctionType,
                         types.BuiltinMethodType, RegexType, float,
                         type(None), compat.FileType)) or
              type(start).__name__ in ('wrapper_descriptor',
                                       'method_descriptor', 'member_descriptor',
                                       'getset_descriptor')):
            pass
        elif showUnknowns:
            print('unknown type', type(start), start)
        return paths