]> granicus.if.org Git - python/commitdiff
Issue #2534: speed up isinstance() and issubclass() by 50-70%, so as to
authorAntoine Pitrou <solipsis@pitrou.net>
Tue, 26 Aug 2008 22:42:08 +0000 (22:42 +0000)
committerAntoine Pitrou <solipsis@pitrou.net>
Tue, 26 Aug 2008 22:42:08 +0000 (22:42 +0000)
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.

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

index 04c007a47dcf5f242538b1b73c53f7ed551ff851..f3bc8bcd0fe9f5de553a0f144589a2c85cb95be8 100644 (file)
@@ -1377,6 +1377,11 @@ PyAPI_FUNC(int) PyObject_IsSubclass(PyObject *object, PyObject *typeorclass);
       /* issubclass(object, typeorclass) */
 
 
+PyAPI_FUNC(int) _PyObject_RealIsInstance(PyObject *inst, PyObject *cls);
+
+PyAPI_FUNC(int) _PyObject_RealIsSubclass(PyObject *derived, PyObject *cls);
+
+
 #ifdef __cplusplus
 }
 #endif
index 8fed220d22c9be6fe84c9ac9683c96c9ccc249a8..3e0955fd75ffcb6d009ae6c1a89db1d10641d5ea 100644 (file)
@@ -88,15 +88,21 @@ class TestABC(unittest.TestCase):
             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:
@@ -105,20 +111,26 @@ class TestABC(unittest.TestCase):
             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
         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(basestring)
         self.assertEqual(isinstance("", A), True)
+        self.assertEqual(isinstance("", (A,)), True)
         self.assertEqual(issubclass(str, A), True)
+        self.assertEqual(issubclass(str, (A,)), True)
 
     def test_registration_edge_cases(self):
         class A:
@@ -141,29 +153,40 @@ class TestABC(unittest.TestCase):
         class A:
             __metaclass__ = abc.ABCMeta
         self.failUnless(issubclass(A, A))
+        self.failUnless(issubclass(A, (A,)))
         class B:
             __metaclass__ = abc.ABCMeta
         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
         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:
index c3a93082bf533f8cc82a0f90a0700b97bd8cf621..0576b6249f27efee45207a472b2b05955acbf85d 100644 (file)
@@ -333,7 +333,19 @@ class ExceptionTests(unittest.TestCase):
                 return g()
             except ValueError:
                 return -1
-        self.assertRaises(RuntimeError, g)
+
+        # The test prints an unraisable recursion error when
+        # doing "except ValueError", this is because subclass
+        # checking has recursion checking too.
+        with captured_output("stderr"):
+            try:
+                g()
+            except RuntimeError:
+                pass
+            except:
+                self.fail("Should have raised KeyError")
+            else:
+                self.fail("Should have raised KeyError")
 
     def testUnicodeStrUsage(self):
         # Make sure both instances and classes have a str and unicode
@@ -363,12 +375,20 @@ class ExceptionTests(unittest.TestCase):
             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 "
-                         "<type 'exceptions.KeyError'> ignored\n")
+                self.fail("Should have raised KeyError")
+
+        with captured_output("stderr") as stderr:
+            def g():
+                try:
+                    return g()
+                except RuntimeError:
+                    return sys.exc_info()
+            e, v, tb = g()
+            self.assert_(e is RuntimeError, e)
+            self.assert_("maximum recursion depth exceeded" in str(v), v)
+
 
 def test_main():
     run_unittest(ExceptionTests)
index 21be62df352006621d95202cc48a8dbf4a526b39..32aa660346f3360a5badada8ee988dd620ca3636 100644 (file)
@@ -41,26 +41,39 @@ class TypeChecksTest(unittest.TestCase):
 
     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 testInfiniteRecursionCaughtProperly(self):
         e = Evil()
index f1aec999d876b394b09a0cf0c9f4f4780de312f3..822d1c956a41f18ca2b176b23fe60d9d29f31a48 100644 (file)
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,13 @@ What's New in Python 2.6 release candidate 1?
 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.
+
 - Fix crashes on memory allocation failure found with failmalloc.
 
 - Fix memory leaks found with valgrind and update suppressions file.
index 68e15491b60369e10254a556a41233761707ea40..956c4f4996933928cf5e52d57ab78ab02a466af3 100644 (file)
@@ -2778,39 +2778,38 @@ abstract_get_bases(PyObject *cls)
 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
@@ -2828,7 +2827,7 @@ check_class(PyObject *cls, const char *error)
 }
 
 static int
-recursive_isinstance(PyObject *inst, PyObject *cls, int recursion_depth)
+recursive_isinstance(PyObject *inst, PyObject *cls)
 {
        PyObject *icls;
        static PyObject *__class__ = NULL;
@@ -2862,25 +2861,6 @@ recursive_isinstance(PyObject *inst, PyObject *cls, int recursion_depth)
                        }
                }
        }
-       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,"
@@ -2910,6 +2890,24 @@ PyObject_IsInstance(PyObject *inst, PyObject *cls)
        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 = PyString_InternFromString("__instancecheck__");
                if (name == NULL)
@@ -2934,47 +2932,28 @@ PyObject_IsInstance(PyObject *inst, PyObject *cls)
                }
                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 (!PyClass_Check(derived) || !PyClass_Check(cls)) {
                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;
-               }
-
+               if (!check_class(cls,
+                               "issubclass() arg 2 must be a class"
+                               " or tuple of classes"))
+                       return -1;
                retval = abstract_issubclass(derived, cls);
        }
        else {
@@ -2992,20 +2971,40 @@ PyObject_IsSubclass(PyObject *derived, PyObject *cls)
        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 = PyString_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);
@@ -3015,7 +3014,19 @@ PyObject_IsSubclass(PyObject *derived, PyObject *cls)
                }
                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);
 }
 
 
index 02b50128cb1c387ddaa07fa90601a25f3272e79e..405b77376c5637989cc180ec110f3e39f38f9315 100644 (file)
@@ -571,6 +571,49 @@ type_get_doc(PyTypeObject *type, void *context)
        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},
@@ -579,6 +622,8 @@ static PyGetSetDef type_getsets[] = {
         (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}
 };
 
index 5d9cab5a4c13884227269117927b98665822d76a..c88a1909c7fb86b710fe18f2327d7b6a95e99818 100644 (file)
@@ -113,7 +113,6 @@ PyErr_GivenExceptionMatches(PyObject *err, PyObject *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);