From 57bd60b465bddf801d0deb094f5ea671ab89068a Mon Sep 17 00:00:00 2001 From: Jeffrey Yasskin Date: Wed, 13 Feb 2008 17:58:04 +0000 Subject: Working on issue #1762: Brought ./python.exe -m timeit -s 'from fractions import Fraction; f = Fraction(3, 2)' 'isinstance(3, Fraction); isinstance(f, Fraction)' from 12.3 usec/loop to 3.44 usec/loop and ./python.exe -m timeit -s 'from fractions import Fraction' 'Fraction(3, 2)' from 48.8 usec to 23.6 usec by avoiding genexps and sets in __instancecheck__ and inlining the common case from __subclasscheck__. --- Lib/abc.py | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'Lib/abc.py') diff --git a/Lib/abc.py b/Lib/abc.py index 1ce38a81c8..9d15012c30 100644 --- a/Lib/abc.py +++ b/Lib/abc.py @@ -163,8 +163,20 @@ class ABCMeta(type): def __instancecheck__(cls, instance): """Override for isinstance(instance, cls).""" - return any(cls.__subclasscheck__(c) - for c in set([instance.__class__, type(instance)])) + # Inline the cache checking for new-style classes. + subclass = instance.__class__ + if subclass in cls._abc_cache: + return True + subtype = type(instance) + if subtype is subclass: + if (cls._abc_negative_cache_version == + ABCMeta._abc_invalidation_counter and + subclass in cls._abc_negative_cache): + return False + # Fall back to the subclass check. + return cls.__subclasscheck__(subclass) + return (cls.__subclasscheck__(subclass) or + cls.__subclasscheck__(subtype)) def __subclasscheck__(cls, subclass): """Override for issubclass(subclass, cls).""" -- cgit v1.2.1