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Major refactoring of django.dispatch with an eye towards speed. The net result is that signals are up to 90% faster.

Browse Source 
Though some attempts and backwards-compatibility were made, speed trumped compatibility. Thus, as usual, check BackwardsIncompatibleChanges for the complete list of backwards-incompatible changes.

Thanks to Jeremy Dunck and Keith Busell for the bulk of the work; some ideas from Brian Herring's previous work (refs #4561) were incorporated.

Documentation is, sigh, still forthcoming.

Fixes #6814 and #3951 (with the new dispatch_uid argument to connect).


git-svn-id: http://code.djangoproject.com/svn/django/trunk@8223 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Jacob Kaplan-Moss
2008-08-06 15:32:46 +00:00
parent d06b474251
commit 34a3bd5225
33 changed files with 380 additions and 848 deletions
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11
django/dispatch/__init__.py
View File

@@ -1,6 +1,9 @@
"""Multi-consumer multi-producer dispatching mechanism
"""
__version__ = "1.0.0"
__author__ = "Patrick K. O'Brien"
__license__ = "BSD-style, see license.txt for details"
Originally based on pydispatch (BSD) http://pypi.python.org/pypi/PyDispatcher/2.0.1
See license.txt for original license.
Heavily modified for Django's purposes.
"""
from django.dispatch.dispatcher import Signal

682
django/dispatch/dispatcher.py
View File

@@ -1,495 +1,243 @@
"""Multiple-producer-multiple-consumer signal-dispatching
dispatcher is the core of the PyDispatcher system,
providing the primary API and the core logic for the
system.
Module attributes of note:
Any -- Singleton used to signal either "Any Sender" or
"Any Signal". See documentation of the _Any class.
Anonymous -- Singleton used to signal "Anonymous Sender"
See documentation of the _Anonymous class.
Internal attributes:
WEAKREF_TYPES -- tuple of types/classes which represent
weak references to receivers, and thus must be de-
referenced on retrieval to retrieve the callable
object
connections -- { senderkey (id) : { signal : [receivers...]}}
senders -- { senderkey (id) : weakref(sender) }
used for cleaning up sender references on sender
deletion
sendersBack -- { receiverkey (id) : [senderkey (id)...] }
used for cleaning up receiver references on receiver
deletion, (considerably speeds up the cleanup process
vs. the original code.)
"""
import weakref
from django.dispatch import saferef, robustapply, errors
import warnings
try:
set
except NameError:
from sets import Set as set # Python 2.3 fallback
__author__ = "Patrick K. O'Brien <pobrien@orbtech.com>"
__cvsid__ = "$Id: dispatcher.py,v 1.9 2005/09/17 04:55:57 mcfletch Exp $"
__version__ = "$Revision: 1.9 $"[11:-2]
class _Parameter:
"""Used to represent default parameter values."""
def __repr__(self):
return self.__class__.__name__
class _Any(_Parameter):
"""Singleton used to signal either "Any Sender" or "Any Signal"
The Any object can be used with connect, disconnect,
send, or sendExact to signal that the parameter given
Any should react to all senders/signals, not just
a particular sender/signal.
"""
Any = _Any()
class _Anonymous(_Parameter):
"""Singleton used to signal "Anonymous Sender"
The Anonymous object is used to signal that the sender
of a message is not specified (as distinct from being
"any sender"). Registering callbacks for Anonymous
will only receive messages sent without senders. Sending
with anonymous will only send messages to those receivers
registered for Any or Anonymous.
Note:
The default sender for connect is Any, while the
default sender for send is Anonymous. This has
the effect that if you do not specify any senders
in either function then all messages are routed
as though there was a single sender (Anonymous)
being used everywhere.
"""
Anonymous = _Anonymous()
from django.dispatch import saferef
WEAKREF_TYPES = (weakref.ReferenceType, saferef.BoundMethodWeakref)
connections = {}
senders = {}
sendersBack = {}
def _make_id(target):
if hasattr(target, 'im_func'):
return (id(target.im_self), id(target.im_func))
return id(target)
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).
class Signal(object):
"""Base class for all signals
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
Internal attributes:
receivers -- { receriverkey (id) : weakref(receiver) }
"""
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
def __init__(self, providing_args=None):
"""providing_args -- A list of the arguments this signal can pass along in
a send() call.
"""
self.receivers = []
if providing_args is None:
providing_args = []
self.providing_args = set(providing_args)
def connect(self, receiver, sender=None, weak=True, dispatch_uid=None):
"""Connect receiver to sender for signal
if Any, receiver will receive the indicated signals
from any sender.
receiver -- a function or an instance method which is to
receive signals. 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).
if Anonymous, receiver will only receive indicated
signals from send/sendExact which do not specify a
sender, or specify Anonymous explicitly as the sender.
Receivers must be able to accept keyword arguments.
Otherwise can be any python object.
If receivers have a dispatch_uid attribute, the receiver will
not be added if another receiver already exists with that
dispatch_uid.
sender -- the sender to which the receiver should respond
Must either be of type Signal, or None to receive events
from any sender.
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.
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.
dispatch_uid -- an identifier used to uniquely identify a particular
instance of a receiver. This will usually be a string, though it
may be anything hashable.
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)
signals = connections.setdefault(senderkey, {})
# 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
returns None
"""
from django.conf import settings
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)
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.
if settings.DEBUG:
import inspect
assert inspect.getargspec(receiver)[2] is not None, \
"Signal receivers must accept keyword arguments (**kwargs)."
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 getReceivers(sender=Any, signal=Any):
"""Get list of receivers from global tables
This utility function allows you to retrieve the
raw list of receivers from the connections table
for the given sender and signal pair.
Note:
there is no guarantee that this is the actual list
stored in the connections table, so the value
should be treated as a simple iterable/truth value
rather than, for instance a list to which you
might append new records.
Normally you would use liveReceivers(getReceivers(...))
to retrieve the actual receiver objects as an iterable
object.
"""
existing = connections.get(id(sender))
if existing is not None:
return existing.get(signal, [])
return []
def liveReceivers(receivers):
"""Filter sequence of receivers to get resolved, live receivers
This is a generator which will iterate over
the passed sequence, checking for weak references
and resolving them, then returning all live
receivers.
"""
for receiver in receivers:
if isinstance(receiver, WEAKREF_TYPES):
# Dereference the weak reference.
receiver = receiver()
if receiver is not None:
yield receiver
if dispatch_uid:
lookup_key = (dispatch_uid, _make_id(sender))
else:
yield receiver
lookup_key = (_make_id(receiver), _make_id(sender))
if weak:
receiver = saferef.safeRef(receiver, onDelete=self._remove_receiver)
def getAllReceivers(sender=Any, signal=Any):
"""Get list of all receivers from global tables
This gets all dereferenced receivers which should receive
the given signal from sender, each receiver should
be produced only once by the resulting generator
"""
receivers = {}
# Get receivers that receive *this* signal from *this* sender.
# Add receivers that receive *any* signal from *this* sender.
# Add receivers that receive *this* signal from *any* sender.
# Add receivers that receive *any* signal from *any* sender.
l = []
i = id(sender)
if i in connections:
sender_receivers = connections[i]
if signal in sender_receivers:
l.extend(sender_receivers[signal])
if signal is not Any and Any in sender_receivers:
l.extend(sender_receivers[Any])
if sender is not Any:
i = id(Any)
if i in connections:
sender_receivers = connections[i]
if sender_receivers is not None:
if signal in sender_receivers:
l.extend(sender_receivers[signal])
if signal is not Any and Any in sender_receivers:
l.extend(sender_receivers[Any])
for receiver in l:
try:
if not receiver in receivers:
if isinstance(receiver, WEAKREF_TYPES):
receiver = receiver()
# this should only (rough guess) be possible if somehow, deref'ing
# triggered a wipe.
if receiver is None:
continue
receivers[receiver] = 1
yield receiver
except TypeError:
# dead weakrefs raise TypeError on hash...
pass
def send(signal=Any, sender=Anonymous, *arguments, **named):
"""Send signal from sender to all connected receivers.
signal -- (hashable) signal value, see connect for details
sender -- the sender of the signal
if Any, only receivers registered for Any will receive
the message.
if Anonymous, only receivers registered to receive
messages from Anonymous or Any will receive the message
Otherwise can be any python object (normally one
registered with a connect if you actually want
something to occur).
arguments -- positional arguments which will be passed to
*all* receivers. Note that this may raise TypeErrors
if the receivers do not allow the particular arguments.
Note also that arguments are applied before named
arguments, so they should be used with care.
named -- named arguments which will be filtered according
to the parameters of the receivers to only provide those
acceptable to the receiver.
Return a list of tuple pairs [(receiver, response), ... ]
if any receiver raises an error, the error propagates back
through send, terminating the dispatch loop, so it is quite
possible to not have all receivers called if a raises an
error.
"""
# Call each receiver with whatever arguments it can accept.
# Return a list of tuple pairs [(receiver, response), ... ].
responses = []
for receiver in getAllReceivers(sender, signal):
response = robustapply.robustApply(
receiver,
signal=signal,
sender=sender,
*arguments,
**named
)
responses.append((receiver, response))
return responses
def sendExact(signal=Any, sender=Anonymous, *arguments, **named ):
"""Send signal only to those receivers registered for exact message
sendExact allows for avoiding Any/Anonymous registered
handlers, sending only to those receivers explicitly
registered for a particular signal on a particular
sender.
"""
responses = []
for receiver in liveReceivers(getReceivers(sender, signal)):
response = robustapply.robustApply(
receiver,
signal=signal,
sender=sender,
*arguments,
**named
)
responses.append((receiver, response))
return responses
def _removeReceiver(receiver):
"""Remove receiver from connections."""
if not sendersBack:
# During module cleanup the mapping will be replaced with None
return False
backKey = id(receiver)
for senderkey in sendersBack.get(backKey,()):
try:
signals = connections[senderkey].keys()
except KeyError,err:
pass
for r_key, _ in self.receivers:
if r_key == lookup_key:
break
else:
for signal in signals:
try:
receivers = connections[senderkey][signal]
except KeyError:
pass
else:
try:
receivers.remove(receiver)
except Exception, err:
pass
_cleanupConnections(senderkey, signal)
try:
del sendersBack[ backKey ]
except KeyError:
pass
def _cleanupConnections(senderkey, signal):
"""Delete any empty signals for senderkey. Delete senderkey if empty."""
try:
receivers = connections[senderkey][signal]
except:
pass
else:
if not receivers:
# No more connected receivers. Therefore, remove the signal.
self.receivers.append((lookup_key, receiver))
def disconnect(self, receiver=None, sender=None, weak=True, dispatch_uid=None):
"""Disconnect receiver from sender for signal
receiver -- the registered receiver to disconnect. May be none if
dispatch_uid is specified.
sender -- the registered sender to disconnect
weak -- the weakref state to disconnect
dispatch_uid -- the unique identifier of the receiver to disconnect
disconnect reverses the process of connect.
If weak references are used, disconnect need not be called.
The receiver will be remove from dispatch automatically.
returns None
"""
if dispatch_uid:
lookup_key = (dispatch_uid, _make_id(sender))
else:
lookup_key = (_make_id(receiver), _make_id(sender))
for idx, (r_key, _) in enumerate(self.receivers):
if r_key == lookup_key:
del self.receivers[idx]
def send(self, sender, **named):
"""Send signal from sender to all connected receivers.
sender -- the sender of the signal
Either a specific object or None.
named -- named arguments which will be passed to receivers.
Returns a list of tuple pairs [(receiver, response), ... ].
If any receiver raises an error, the error propagates back
through send, terminating the dispatch loop, so it is quite
possible to not have all receivers called if a raises an
error.
"""
responses = []
if not self.receivers:
return responses
for receiver in self._live_receivers(_make_id(sender)):
response = receiver(signal=self, sender=sender, **named)
responses.append((receiver, response))
return responses
def send_robust(self, sender, **named):
"""Send signal from sender to all connected receivers catching errors
sender -- the sender of the signal
Can be any python object (normally one registered with
a connect if you actually want something to occur).
named -- named arguments which will be passed to receivers.
These arguments must be a subset of the argument names
defined in providing_args.
Return a list of tuple pairs [(receiver, response), ... ],
may raise DispatcherKeyError
if any receiver raises an error (specifically any subclass of Exception),
the error instance is returned as the result for that receiver.
"""
responses = []
if not self.receivers:
return responses
# Call each receiver with whatever arguments it can accept.
# Return a list of tuple pairs [(receiver, response), ... ].
for receiver in self._live_receivers(_make_id(sender)):
try:
signals = connections[senderkey]
except KeyError:
pass
response = receiver(signal=self, sender=sender, **named)
except Exception, err:
responses.append((receiver, err))
else:
del signals[signal]
if not signals:
# No more signal connections. Therefore, remove the sender.
_removeSender(senderkey)
responses.append((receiver, response))
return responses
def _removeSender(senderkey):
"""Remove senderkey from connections."""
_removeBackrefs(senderkey)
def _live_receivers(self, senderkey):
"""Filter sequence of receivers to get resolved, live receivers
connections.pop(senderkey, None)
senders.pop(senderkey, None)
This checks for weak references
and resolves them, then returning only live
receivers.
"""
none_senderkey = _make_id(None)
for (receiverkey, r_senderkey), receiver in self.receivers:
if r_senderkey == none_senderkey or r_senderkey == senderkey:
if isinstance(receiver, WEAKREF_TYPES):
# Dereference the weak reference.
receiver = receiver()
if receiver is not None:
yield receiver
else:
yield receiver
def _removeBackrefs(senderkey):
"""Remove all back-references to this senderkey"""
for receiver_list in connections.pop(senderkey, {}).values():
for receiver in receiver_list:
_killBackref(receiver, senderkey)
def _remove_receiver(self, receiver):
"""Remove dead receivers from connections."""
to_remove = []
for key, connected_receiver in self.receivers:
if connected_receiver == receiver:
to_remove.append(key)
for key in to_remove:
for idx, (r_key, _) in enumerate(self.receivers):
if r_key == key:
del self.receivers[idx]
def _removeOldBackRefs(senderkey, signal, receiver, receivers):
"""Kill old sendersBack references from receiver
This guards against multiple registration of the same
receiver for a given signal and sender leaking memory
as old back reference records build up.
Also removes old receiver instance from receivers
def connect(receiver, signal, sender=None, weak=True):
"""
try:
index = receivers.index(receiver)
# need to scan back references here and remove senderkey
except ValueError:
return False
else:
oldReceiver = receivers[index]
del receivers[index]
found = 0
signals = connections.get(signal)
if signals is not None:
for sig,recs in connections.get(signal,{}).iteritems():
if sig != signal:
for rec in recs:
if rec is oldReceiver:
found = 1
break
if not found:
_killBackref(oldReceiver, senderkey)
return True
return False
def _killBackref(receiver, senderkey):
"""Do the actual removal of back reference from receiver to senderkey"""
receiverkey = id(receiver)
receivers_list = sendersBack.get(receiverkey, ())
while senderkey in receivers_list:
try:
receivers_list.remove(senderkey)
except:
break
if not receivers_list:
try:
del sendersBack[ receiverkey ]
except KeyError:
pass
return True
For backward compatibility only. See Signal.connect()
"""
warnings.warn(
category = DeprecationWarning,
message = "dispatcher.connect() is deprecated; use Signal.connect() instead.",
stacklevel = 2
)
return signal.connect(receiver, sender, weak)
def disconnect(receiver, signal, sender=None, weak=True):
"""
For backward compatibility only. See Signal.disconnect()
"""
warnings.warn(
category = DeprecationWarning,
message = "dispatcher.disconnect() is deprecated; use Signal.disconnect() instead.",
stacklevel = 2
)
signal.disconnect(receiver, sender, weak)
def send(signal, sender=None, **named):
"""
For backward compatibility only. See Signal.send()
"""
warnings.warn(
category = DeprecationWarning,
message = "dispatcher.send() is deprecated; use Signal.send() instead.",
stacklevel = 2
)
return signal.send(sender=sender, **named)
def sendExact(signal, sender, **named ):
"""
This function is deprecated, as it now has the same meaning as send.
"""
warnings.warn(
category = DeprecationWarning,
message = "dispatcher.sendExact() is deprecated; use Signal.send() instead.",
stacklevel = 2
)
return signal.send(sender=sender, **named)

10
django/dispatch/errors.py
View File

@@ -1,10 +0,0 @@
"""Error types for dispatcher mechanism
"""
class DispatcherError(Exception):
"""Base class for all Dispatcher errors"""
class DispatcherKeyError(KeyError, DispatcherError):
"""Error raised when unknown (sender,signal) set specified"""
class DispatcherTypeError(TypeError, DispatcherError):
"""Error raised when inappropriate signal-type specified (None)"""

4
django/dispatch/license.txt
View File

@@ -1,4 +1,6 @@
PyDispatcher License
django.dispatch was originally forked from PyDispatcher.
PyDispatcher License:
Copyright (c) 2001-2003, Patrick K. O'Brien and Contributors
All rights reserved.

57
django/dispatch/robust.py
View File

@@ -1,57 +0,0 @@
"""Module implementing error-catching version of send (sendRobust)"""
from django.dispatch.dispatcher import Any, Anonymous, liveReceivers, getAllReceivers
from django.dispatch.robustapply import robustApply
def sendRobust(
signal=Any,
sender=Anonymous,
*arguments, **named
):
"""Send signal from sender to all connected receivers catching errors
signal -- (hashable) signal value, see connect for details
sender -- the sender of the signal
if Any, only receivers registered for Any will receive
the message.
if Anonymous, only receivers registered to receive
messages from Anonymous or Any will receive the message
Otherwise can be any python object (normally one
registered with a connect if you actually want
something to occur).
arguments -- positional arguments which will be passed to
*all* receivers. Note that this may raise TypeErrors
if the receivers do not allow the particular arguments.
Note also that arguments are applied before named
arguments, so they should be used with care.
named -- named arguments which will be filtered according
to the parameters of the receivers to only provide those
acceptable to the receiver.
Return a list of tuple pairs [(receiver, response), ... ]
if any receiver raises an error (specifically any subclass of Exception),
the error instance is returned as the result for that receiver.
"""
# Call each receiver with whatever arguments it can accept.
# Return a list of tuple pairs [(receiver, response), ... ].
responses = []
for receiver in liveReceivers(getAllReceivers(sender, signal)):
try:
response = robustApply(
receiver,
signal=signal,
sender=sender,
*arguments,
**named
)
except Exception, err:
responses.append((receiver, err))
else:
responses.append((receiver, response))
return responses

47
django/dispatch/robustapply.py
View File

@@ -1,47 +0,0 @@
"""Robust apply mechanism
Provides a function "call", which can sort out
what arguments a given callable object can take,
and subset the given arguments to match only
those which are acceptable.
"""
def function( receiver ):
"""Get function-like callable object for given receiver
returns (function_or_method, codeObject, fromMethod)
If fromMethod is true, then the callable already
has its first argument bound
"""
if hasattr(receiver, '__call__'):
# receiver is a class instance; assume it is callable.
# Reassign receiver to the actual method that will be called.
if hasattr( receiver.__call__, 'im_func') or hasattr( receiver.__call__, 'im_code'):
receiver = receiver.__call__
if hasattr( receiver, 'im_func' ):
# an instance-method...
return receiver, receiver.im_func.func_code, 1
elif not hasattr( receiver, 'func_code'):
raise ValueError('unknown reciever type %s %s'%(receiver, type(receiver)))
return receiver, receiver.func_code, 0
def robustApply(receiver, *arguments, **named):
"""Call receiver with arguments and an appropriate subset of named
"""
receiver, codeObject, startIndex = function( receiver )
acceptable = codeObject.co_varnames[startIndex+len(arguments):codeObject.co_argcount]
for name in codeObject.co_varnames[startIndex:startIndex+len(arguments)]:
if named.has_key( name ):
raise TypeError(
"""Argument %r specified both positionally and as a keyword for calling %r"""% (
name, receiver,
)
)
if not (codeObject.co_flags & 8):
# fc does not have a **kwds type parameter, therefore
# remove unacceptable arguments.
for arg in named.keys():
if arg not in acceptable:
del named[arg]
return receiver(*arguments, **named)

19
django/dispatch/saferef.py
View File

@@ -1,4 +1,10 @@
"""Refactored "safe reference" from dispatcher.py"""
"""
"Safe weakrefs", originally from pyDispatcher.
Provides a way to safely weakref any function, including bound methods (which
aren't handled by the core weakref module).
"""
import weakref, traceback
def safeRef(target, onDelete = None):
@@ -60,7 +66,9 @@ class BoundMethodWeakref(object):
same BoundMethodWeakref instance.
"""
_allInstances = weakref.WeakValueDictionary()
def __new__( cls, target, onDelete=None, *arguments,**named ):
"""Create new instance or return current instance
@@ -83,6 +91,7 @@ class BoundMethodWeakref(object):
cls._allInstances[key] = base
base.__init__( target, onDelete, *arguments,**named)
return base
def __init__(self, target, onDelete=None):
"""Return a weak-reference-like instance for a bound method
@@ -122,6 +131,7 @@ class BoundMethodWeakref(object):
self.weakFunc = weakref.ref(target.im_func, remove)
self.selfName = str(target.im_self)
self.funcName = str(target.im_func.__name__)
def calculateKey( cls, target ):
"""Calculate the reference key for this reference
@@ -130,6 +140,7 @@ class BoundMethodWeakref(object):
"""
return (id(target.im_self),id(target.im_func))
calculateKey = classmethod( calculateKey )
def __str__(self):
"""Give a friendly representation of the object"""
return """%s( %s.%s )"""%(
@@ -137,15 +148,19 @@ class BoundMethodWeakref(object):
self.selfName,
self.funcName,
)
__repr__ = __str__
def __nonzero__( self ):
"""Whether we are still a valid reference"""
return self() is not None
def __cmp__( self, other ):
"""Compare with another reference"""
if not isinstance (other,self.__class__):
return cmp( self.__class__, type(other) )
return cmp( self.key, other.key)
def __call__(self):
"""Return a strong reference to the bound method
@@ -224,7 +239,6 @@ class BoundNonDescriptorMethodWeakref(BoundMethodWeakref):
return getattr(target, function.__name__)
return None
def get_bound_method_weakref(target, onDelete):
"""Instantiates the appropiate BoundMethodWeakRef, depending on the details of
the underlying class method implementation"""
@@ -234,4 +248,3 @@ def get_bound_method_weakref(target, onDelete):
else:
# no luck, use the alternative implementation:
return BoundNonDescriptorMethodWeakref(target=target, onDelete=onDelete)