Discussion:
[Python-3000-checkins] r66042 - in python/branches/py3k: Include/abstract.h Lib/test/test_abc.py Lib/test/test_exceptions.py Lib/test/test_typechecks.py Misc/NEWS Objects/abstract.c Objects/typeobject.c Python/errors.c
antoine.pitrou
2008-08-26 22:40:49 UTC
Permalink
Author: antoine.pitrou
Date: Wed Aug 27 00:40:48 2008
New Revision: 66042

Log:
Issue #2534: speed up isinstance() and issubclass() by 50-70%, so as to
match Python 2.5 speed despite the __instancecheck__ / __subclasscheck__
mechanism. In the process, fix a bug where isinstance() and issubclass(),
when given a tuple of classes as second argument, were looking up
__instancecheck__ / __subclasscheck__ on the tuple rather than on each
type object.

Reviewed by Benjamin Peterson and Raymond Hettinger.




Modified:
python/branches/py3k/Include/abstract.h
python/branches/py3k/Lib/test/test_abc.py
python/branches/py3k/Lib/test/test_exceptions.py
python/branches/py3k/Lib/test/test_typechecks.py
python/branches/py3k/Misc/NEWS
python/branches/py3k/Objects/abstract.c
python/branches/py3k/Objects/typeobject.c
python/branches/py3k/Python/errors.c

Modified: python/branches/py3k/Include/abstract.h
==============================================================================
--- python/branches/py3k/Include/abstract.h (original)
+++ python/branches/py3k/Include/abstract.h Wed Aug 27 00:40:48 2008
@@ -1273,6 +1273,11 @@
/* issubclass(object, typeorclass) */


+PyAPI_FUNC(int) _PyObject_RealIsInstance(PyObject *inst, PyObject *cls);
+
+PyAPI_FUNC(int) _PyObject_RealIsSubclass(PyObject *derived, PyObject *cls);
+
+
#ifdef __cplusplus
}
#endif

Modified: python/branches/py3k/Lib/test/test_abc.py
==============================================================================
--- python/branches/py3k/Lib/test/test_abc.py (original)
+++ python/branches/py3k/Lib/test/test_abc.py Wed Aug 27 00:40:48 2008
@@ -75,15 +75,21 @@
pass
b = B()
self.assertEqual(issubclass(B, A), False)
+ self.assertEqual(issubclass(B, (A,)), False)
self.assertEqual(isinstance(b, A), False)
+ self.assertEqual(isinstance(b, (A,)), False)
A.register(B)
self.assertEqual(issubclass(B, A), True)
+ self.assertEqual(issubclass(B, (A,)), True)
self.assertEqual(isinstance(b, A), True)
+ self.assertEqual(isinstance(b, (A,)), True)
class C(B):
pass
c = C()
self.assertEqual(issubclass(C, A), True)
+ self.assertEqual(issubclass(C, (A,)), True)
self.assertEqual(isinstance(c, A), True)
+ self.assertEqual(isinstance(c, (A,)), True)

def test_isinstance_invalidation(self):
class A(metaclass=abc.ABCMeta):
@@ -92,22 +98,29 @@
pass
b = B()
self.assertEqual(isinstance(b, A), False)
+ self.assertEqual(isinstance(b, (A,)), False)
A.register(B)
self.assertEqual(isinstance(b, A), True)
+ self.assertEqual(isinstance(b, (A,)), True)

def test_registration_builtins(self):
class A(metaclass=abc.ABCMeta):
pass
A.register(int)
self.assertEqual(isinstance(42, A), True)
+ self.assertEqual(isinstance(42, (A,)), True)
self.assertEqual(issubclass(int, A), True)
+ self.assertEqual(issubclass(int, (A,)), True)
class B(A):
pass
B.register(str)
class C(str): pass
self.assertEqual(isinstance("", A), True)
+ self.assertEqual(isinstance("", (A,)), True)
self.assertEqual(issubclass(str, A), True)
+ self.assertEqual(issubclass(str, (A,)), True)
self.assertEqual(issubclass(C, A), True)
+ self.assertEqual(issubclass(C, (A,)), True)

def test_registration_edge_cases(self):
class A(metaclass=abc.ABCMeta):
@@ -130,29 +143,40 @@
class A(metaclass=abc.ABCMeta):
pass
self.failUnless(issubclass(A, A))
+ self.failUnless(issubclass(A, (A,)))
class B(metaclass=abc.ABCMeta):
pass
self.failIf(issubclass(A, B))
+ self.failIf(issubclass(A, (B,)))
self.failIf(issubclass(B, A))
+ self.failIf(issubclass(B, (A,)))
class C(metaclass=abc.ABCMeta):
pass
A.register(B)
class B1(B):
pass
self.failUnless(issubclass(B1, A))
+ self.failUnless(issubclass(B1, (A,)))
class C1(C):
pass
B1.register(C1)
self.failIf(issubclass(C, B))
+ self.failIf(issubclass(C, (B,)))
self.failIf(issubclass(C, B1))
+ self.failIf(issubclass(C, (B1,)))
self.failUnless(issubclass(C1, A))
+ self.failUnless(issubclass(C1, (A,)))
self.failUnless(issubclass(C1, B))
+ self.failUnless(issubclass(C1, (B,)))
self.failUnless(issubclass(C1, B1))
+ self.failUnless(issubclass(C1, (B1,)))
C1.register(int)
class MyInt(int):
pass
self.failUnless(issubclass(MyInt, A))
+ self.failUnless(issubclass(MyInt, (A,)))
self.failUnless(isinstance(42, A))
+ self.failUnless(isinstance(42, (A,)))

def test_all_new_methods_are_called(self):
class A(metaclass=abc.ABCMeta):

Modified: python/branches/py3k/Lib/test/test_exceptions.py
==============================================================================
--- python/branches/py3k/Lib/test/test_exceptions.py (original)
+++ python/branches/py3k/Lib/test/test_exceptions.py Wed Aug 27 00:40:48 2008
@@ -582,12 +582,18 @@
except KeyError:
pass
except:
- self.fail("Should have raised TypeError")
+ self.fail("Should have raised KeyError")
else:
- self.fail("Should have raised TypeError")
- self.assertEqual(stderr.getvalue(),
- "Exception ValueError: ValueError() "
- "in <class 'KeyError'> ignored\n")
+ self.fail("Should have raised KeyError")
+
+ def g():
+ try:
+ return g()
+ except RuntimeError:
+ return sys.exc_info()
+ e, v, tb = g()
+ self.assert_(isinstance(v, RuntimeError), type(v))
+ self.assert_("maximum recursion depth exceeded" in str(v), str(v))


def test_MemoryError(self):

Modified: python/branches/py3k/Lib/test/test_typechecks.py
==============================================================================
--- python/branches/py3k/Lib/test/test_typechecks.py (original)
+++ python/branches/py3k/Lib/test/test_typechecks.py Wed Aug 27 00:40:48 2008
@@ -33,26 +33,39 @@

def testIsSubclassBuiltin(self):
self.assertEqual(issubclass(int, Integer), True)
+ self.assertEqual(issubclass(int, (Integer,)), True)
self.assertEqual(issubclass(float, Integer), False)
+ self.assertEqual(issubclass(float, (Integer,)), False)

def testIsInstanceBuiltin(self):
self.assertEqual(isinstance(42, Integer), True)
+ self.assertEqual(isinstance(42, (Integer,)), True)
self.assertEqual(isinstance(3.14, Integer), False)
+ self.assertEqual(isinstance(3.14, (Integer,)), False)

def testIsInstanceActual(self):
self.assertEqual(isinstance(Integer(), Integer), True)
+ self.assertEqual(isinstance(Integer(), (Integer,)), True)

def testIsSubclassActual(self):
self.assertEqual(issubclass(Integer, Integer), True)
+ self.assertEqual(issubclass(Integer, (Integer,)), True)

def testSubclassBehavior(self):
self.assertEqual(issubclass(SubInt, Integer), True)
+ self.assertEqual(issubclass(SubInt, (Integer,)), True)
self.assertEqual(issubclass(SubInt, SubInt), True)
+ self.assertEqual(issubclass(SubInt, (SubInt,)), True)
self.assertEqual(issubclass(Integer, SubInt), False)
+ self.assertEqual(issubclass(Integer, (SubInt,)), False)
self.assertEqual(issubclass(int, SubInt), False)
+ self.assertEqual(issubclass(int, (SubInt,)), False)
self.assertEqual(isinstance(SubInt(), Integer), True)
+ self.assertEqual(isinstance(SubInt(), (Integer,)), True)
self.assertEqual(isinstance(SubInt(), SubInt), True)
+ self.assertEqual(isinstance(SubInt(), (SubInt,)), True)
self.assertEqual(isinstance(42, SubInt), False)
+ self.assertEqual(isinstance(42, (SubInt,)), False)


def test_main():

Modified: python/branches/py3k/Misc/NEWS
==============================================================================
--- python/branches/py3k/Misc/NEWS (original)
+++ python/branches/py3k/Misc/NEWS Wed Aug 27 00:40:48 2008
@@ -12,6 +12,13 @@
Core and Builtins
-----------------

+- Issue #2534: speed up isinstance() and issubclass() by 50-70%, so as to
+ match Python 2.5 speed despite the __instancecheck__ / __subclasscheck__
+ mechanism. In the process, fix a bug where isinstance() and issubclass(),
+ when given a tuple of classes as second argument, were looking up
+ __instancecheck__ / __subclasscheck__ on the tuple rather than on each
+ type object.
+
- Issue #3663: Py_None was decref'd when printing SyntaxErrors.

- Issue #3657: Fix uninitialized memory read when pickling longs.

Modified: python/branches/py3k/Objects/abstract.c
==============================================================================
--- python/branches/py3k/Objects/abstract.c (original)
+++ python/branches/py3k/Objects/abstract.c Wed Aug 27 00:40:48 2008
@@ -2474,39 +2474,38 @@
static int
abstract_issubclass(PyObject *derived, PyObject *cls)
{
- PyObject *bases;
+ PyObject *bases = NULL;
Py_ssize_t i, n;
int r = 0;

-
- if (derived == cls)
- return 1;
-
- if (PyTuple_Check(cls)) {
- /* Not a general sequence -- that opens up the road to
- recursion and stack overflow. */
- n = PyTuple_GET_SIZE(cls);
+ while (1) {
+ if (derived == cls)
+ return 1;
+ bases = abstract_get_bases(derived);
+ if (bases == NULL) {
+ if (PyErr_Occurred())
+ return -1;
+ return 0;
+ }
+ n = PyTuple_GET_SIZE(bases);
+ if (n == 0) {
+ Py_DECREF(bases);
+ return 0;
+ }
+ /* Avoid recursivity in the single inheritance case */
+ if (n == 1) {
+ derived = PyTuple_GET_ITEM(bases, 0);
+ Py_DECREF(bases);
+ continue;
+ }
for (i = 0; i < n; i++) {
- if (derived == PyTuple_GET_ITEM(cls, i))
- return 1;
+ r = abstract_issubclass(PyTuple_GET_ITEM(bases, i), cls);
+ if (r != 0)
+ break;
}
+ Py_DECREF(bases);
+ return r;
}
- bases = abstract_get_bases(derived);
- if (bases == NULL) {
- if (PyErr_Occurred())
- return -1;
- return 0;
- }
- n = PyTuple_GET_SIZE(bases);
- for (i = 0; i < n; i++) {
- r = abstract_issubclass(PyTuple_GET_ITEM(bases, i), cls);
- if (r != 0)
- break;
- }
-
- Py_DECREF(bases);
-
- return r;
}

static int
@@ -2524,7 +2523,7 @@
}

static int
-recursive_isinstance(PyObject *inst, PyObject *cls, int recursion_depth)
+recursive_isinstance(PyObject *inst, PyObject *cls)
{
PyObject *icls;
static PyObject *__class__ = NULL;
@@ -2553,25 +2552,6 @@
}
}
}
- else if (PyTuple_Check(cls)) {
- Py_ssize_t i, n;
-
- if (!recursion_depth) {
- PyErr_SetString(PyExc_RuntimeError,
- "nest level of tuple too deep");
- return -1;
- }
-
- n = PyTuple_GET_SIZE(cls);
- for (i = 0; i < n; i++) {
- retval = recursive_isinstance(
- inst,
- PyTuple_GET_ITEM(cls, i),
- recursion_depth-1);
- if (retval != 0)
- break;
- }
- }
else {
if (!check_class(cls,
"isinstance() arg 2 must be a class, type,"
@@ -2601,6 +2581,24 @@
if (Py_TYPE(inst) == (PyTypeObject *)cls)
return 1;

+ if (PyTuple_Check(cls)) {
+ Py_ssize_t i;
+ Py_ssize_t n;
+ int r = 0;
+
+ if (Py_EnterRecursiveCall(" in __instancecheck__"))
+ return -1;
+ n = PyTuple_GET_SIZE(cls);
+ for (i = 0; i < n; ++i) {
+ PyObject *item = PyTuple_GET_ITEM(cls, i);
+ r = PyObject_IsInstance(inst, item);
+ if (r != 0)
+ /* either found it, or got an error */
+ break;
+ }
+ Py_LeaveRecursiveCall();
+ return r;
+ }
if (name == NULL) {
name = PyUnicode_InternFromString("__instancecheck__");
if (name == NULL)
@@ -2625,51 +2623,25 @@
}
return ok;
}
- return recursive_isinstance(inst, cls, Py_GetRecursionLimit());
+ return recursive_isinstance(inst, cls);
}

static int
-recursive_issubclass(PyObject *derived, PyObject *cls, int recursion_depth)
+recursive_issubclass(PyObject *derived, PyObject *cls)
{
- int retval;
+ if (PyType_Check(cls) && PyType_Check(derived)) {
+ /* Fast path (non-recursive) */
+ return PyType_IsSubtype((PyTypeObject *)derived, (PyTypeObject *)cls);
+ }
+ if (!check_class(derived,
+ "issubclass() arg 1 must be a class"))
+ return -1;
+ if (!check_class(cls,
+ "issubclass() arg 2 must be a class"
+ " or tuple of classes"))
+ return -1;

- {
- if (!check_class(derived,
- "issubclass() arg 1 must be a class"))
- return -1;
-
- if (PyTuple_Check(cls)) {
- Py_ssize_t i;
- Py_ssize_t n = PyTuple_GET_SIZE(cls);
-
- if (!recursion_depth) {
- PyErr_SetString(PyExc_RuntimeError,
- "nest level of tuple too deep");
- return -1;
- }
- for (i = 0; i < n; ++i) {
- retval = recursive_issubclass(
- derived,
- PyTuple_GET_ITEM(cls, i),
- recursion_depth-1);
- if (retval != 0) {
- /* either found it, or got an error */
- return retval;
- }
- }
- return 0;
- }
- else {
- if (!check_class(cls,
- "issubclass() arg 2 must be a class"
- " or tuple of classes"))
- return -1;
- }
-
- retval = abstract_issubclass(derived, cls);
- }
-
- return retval;
+ return abstract_issubclass(derived, cls);
}

int
@@ -2678,20 +2650,40 @@
static PyObject *name = NULL;
PyObject *t, *v, *tb;
PyObject *checker;
- PyErr_Fetch(&t, &v, &tb);

+ if (PyTuple_Check(cls)) {
+ Py_ssize_t i;
+ Py_ssize_t n;
+ int r = 0;
+
+ if (Py_EnterRecursiveCall(" in __subclasscheck__"))
+ return -1;
+ n = PyTuple_GET_SIZE(cls);
+ for (i = 0; i < n; ++i) {
+ PyObject *item = PyTuple_GET_ITEM(cls, i);
+ r = PyObject_IsSubclass(derived, item);
+ if (r != 0)
+ /* either found it, or got an error */
+ break;
+ }
+ Py_LeaveRecursiveCall();
+ return r;
+ }
if (name == NULL) {
name = PyUnicode_InternFromString("__subclasscheck__");
if (name == NULL)
return -1;
}
+ PyErr_Fetch(&t, &v, &tb);
checker = PyObject_GetAttr(cls, name);
PyErr_Restore(t, v, tb);
if (checker != NULL) {
PyObject *res;
int ok = -1;
- if (Py_EnterRecursiveCall(" in __subclasscheck__"))
+ if (Py_EnterRecursiveCall(" in __subclasscheck__")) {
+ Py_DECREF(checker);
return ok;
+ }
res = PyObject_CallFunctionObjArgs(checker, derived, NULL);
Py_LeaveRecursiveCall();
Py_DECREF(checker);
@@ -2701,7 +2693,19 @@
}
return ok;
}
- return recursive_issubclass(derived, cls, Py_GetRecursionLimit());
+ return recursive_issubclass(derived, cls);
+}
+
+int
+_PyObject_RealIsInstance(PyObject *inst, PyObject *cls)
+{
+ return recursive_isinstance(inst, cls);
+}
+
+int
+_PyObject_RealIsSubclass(PyObject *derived, PyObject *cls)
+{
+ return recursive_issubclass(derived, cls);
}



Modified: python/branches/py3k/Objects/typeobject.c
==============================================================================
--- python/branches/py3k/Objects/typeobject.c (original)
+++ python/branches/py3k/Objects/typeobject.c Wed Aug 27 00:40:48 2008
@@ -584,6 +584,49 @@
return result;
}

+static PyObject *
+type___instancecheck__(PyObject *type, PyObject *inst)
+{
+ switch (_PyObject_RealIsInstance(inst, type)) {
+ case -1:
+ return NULL;
+ case 0:
+ Py_RETURN_FALSE;
+ default:
+ Py_RETURN_TRUE;
+ }
+}
+
+
+static PyObject *
+type_get_instancecheck(PyObject *type, void *context)
+{
+ static PyMethodDef ml = {"__instancecheck__",
+ type___instancecheck__, METH_O };
+ return PyCFunction_New(&ml, type);
+}
+
+static PyObject *
+type___subclasscheck__(PyObject *type, PyObject *inst)
+{
+ switch (_PyObject_RealIsSubclass(inst, type)) {
+ case -1:
+ return NULL;
+ case 0:
+ Py_RETURN_FALSE;
+ default:
+ Py_RETURN_TRUE;
+ }
+}
+
+static PyObject *
+type_get_subclasscheck(PyObject *type, void *context)
+{
+ static PyMethodDef ml = {"__subclasscheck__",
+ type___subclasscheck__, METH_O };
+ return PyCFunction_New(&ml, type);
+}
+
static PyGetSetDef type_getsets[] = {
{"__name__", (getter)type_name, (setter)type_set_name, NULL},
{"__bases__", (getter)type_get_bases, (setter)type_set_bases, NULL},
@@ -592,6 +635,8 @@
(setter)type_set_abstractmethods, NULL},
{"__dict__", (getter)type_dict, NULL, NULL},
{"__doc__", (getter)type_get_doc, NULL, NULL},
+ {"__instancecheck__", (getter)type_get_instancecheck, NULL, NULL},
+ {"__subclasscheck__", (getter)type_get_subclasscheck, NULL, NULL},
{0}
};


Modified: python/branches/py3k/Python/errors.c
==============================================================================
--- python/branches/py3k/Python/errors.c (original)
+++ python/branches/py3k/Python/errors.c Wed Aug 27 00:40:48 2008
@@ -160,11 +160,12 @@
int res = 0;
PyObject *exception, *value, *tb;
PyErr_Fetch(&exception, &value, &tb);
- res = PyObject_IsSubclass(err, exc);
+ /* PyObject_IsSubclass() can recurse and therefore is
+ not safe (see test_bad_getattr in test.pickletester). */
+ res = PyType_IsSubtype((PyTypeObject *)err, (PyTypeObject *)exc);
/* This function must not fail, so print the error here */
if (res == -1) {
PyErr_WriteUnraisable(err);
- /* issubclass did not succeed */
res = 0;
}
PyErr_Restore(exception, value, tb);

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