mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-08-14 13:59:20 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 11

Use weakrefs to hold onto classes #2521.

Browse source 
This also causes the _weakref module to be built into the core.
This commit is contained in:
Benjamin Peterson 2010-08-21 03:03:22 +00:00
parent b1147f5d0a
commit 52c36051bd
4 changed files with 30 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

11
Lib/abc.py
View file

@ -5,6 +5,7 @@
import types
from _weakrefset import WeakSet
# Instance of old-style class
class _C: pass
@ -95,9 +96,9 @@ class ABCMeta(type):
abstracts.add(name)
cls.__abstractmethods__ = frozenset(abstracts)
# Set up inheritance registry
cls._abc_registry = set()
cls._abc_cache = set()
cls._abc_negative_cache = set()
cls._abc_registry = WeakSet()
cls._abc_cache = WeakSet()
cls._abc_negative_cache = WeakSet()
cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter
return cls
@ -128,7 +129,7 @@ class ABCMeta(type):
"""Override for isinstance(instance, cls)."""
# Inline the cache checking when it's simple.
subclass = getattr(instance, '__class__', None)
if subclass in cls._abc_cache:
if subclass is not None and subclass in cls._abc_cache:
return True
subtype = type(instance)
# Old-style instances
@ -152,7 +153,7 @@ class ABCMeta(type):
# Check negative cache; may have to invalidate
if cls._abc_negative_cache_version < ABCMeta._abc_invalidation_counter:
# Invalidate the negative cache
cls._abc_negative_cache = set()
cls._abc_negative_cache = WeakSet()
cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter
elif subclass in cls._abc_negative_cache:
return False