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Fixed #20943 -- Weakly reference senders when caching their associated receivers

This commit is contained in:
Simon Charette 2013-08-19 23:14:21 -04:00
parent fdbf492946
commit e55ca60903
3 changed files with 30 additions and 5 deletions

View File

@ -13,6 +13,6 @@ pre_delete = Signal(providing_args=["instance", "using"], use_caching=True)
post_delete = Signal(providing_args=["instance", "using"], use_caching=True)
pre_syncdb = Signal(providing_args=["app", "create_models", "verbosity", "interactive", "db"])
post_syncdb = Signal(providing_args=["class", "app", "created_models", "verbosity", "interactive", "db"], use_caching=True)
post_syncdb = Signal(providing_args=["class", "app", "created_models", "verbosity", "interactive", "db"])
m2m_changed = Signal(providing_args=["action", "instance", "reverse", "model", "pk_set", "using"], use_caching=True)

View File

@ -4,8 +4,10 @@ import threading
from django.dispatch import saferef
from django.utils.six.moves import xrange
WEAKREF_TYPES = (weakref.ReferenceType, saferef.BoundMethodWeakref)
def _make_id(target):
if hasattr(target, '__func__'):
return (id(target.__self__), id(target.__func__))
@ -15,6 +17,7 @@ NONE_ID = _make_id(None)
# A marker for caching
NO_RECEIVERS = object()
class Signal(object):
"""
Base class for all signals
@ -42,7 +45,7 @@ class Signal(object):
# distinct sender we cache the receivers that sender has in
# 'sender_receivers_cache'. The cache is cleaned when .connect() or
# .disconnect() is called and populated on send().
self.sender_receivers_cache = {}
self.sender_receivers_cache = weakref.WeakKeyDictionary() if use_caching else {}
def connect(self, receiver, sender=None, weak=True, dispatch_uid=None):
"""
@ -116,7 +119,7 @@ class Signal(object):
break
else:
self.receivers.append((lookup_key, receiver))
self.sender_receivers_cache = {}
self.sender_receivers_cache.clear()
def disconnect(self, receiver=None, sender=None, weak=True, dispatch_uid=None):
"""
@ -151,7 +154,7 @@ class Signal(object):
if r_key == lookup_key:
del self.receivers[index]
break
self.sender_receivers_cache = {}
self.sender_receivers_cache.clear()
def has_listeners(self, sender=None):
return bool(self._live_receivers(sender))
@ -276,7 +279,8 @@ class Signal(object):
for idx, (r_key, _) in enumerate(reversed(self.receivers)):
if r_key == key:
del self.receivers[last_idx - idx]
self.sender_receivers_cache = {}
self.sender_receivers_cache.clear()
def receiver(signal, **kwargs):
"""

View File

@ -2,6 +2,7 @@ import gc
import sys
import time
import unittest
import weakref
from django.dispatch import Signal, receiver
@ -35,6 +36,8 @@ class Callable(object):
a_signal = Signal(providing_args=["val"])
b_signal = Signal(providing_args=["val"])
c_signal = Signal(providing_args=["val"])
d_signal = Signal(providing_args=["val"], use_caching=True)
class DispatcherTests(unittest.TestCase):
"""Test suite for dispatcher (barely started)"""
@ -72,6 +75,24 @@ class DispatcherTests(unittest.TestCase):
self.assertEqual(result, expected)
self._testIsClean(a_signal)
def testCachedGarbagedCollected(self):
"""
Make sure signal caching sender receivers don't prevent garbage
collection of senders.
"""
class sender:
pass
wref = weakref.ref(sender)
d_signal.connect(receiver_1_arg)
d_signal.send(sender, val='garbage')
del sender
garbage_collect()
try:
self.assertIsNone(wref())
finally:
# Disconnect after reference check since it flushes the tested cache.
d_signal.disconnect(receiver_1_arg)
def testMultipleRegistration(self):
a = Callable()
a_signal.connect(a)