]> 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 22:40:48 +0000 (22:40 +0000)
committerAntoine Pitrou <solipsis@pitrou.net>
Tue, 26 Aug 2008 22:40:48 +0000 (22:40 +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 46a6f544a344b13f0a19d6bddc86c90b146e81c1..0bbcee54d963f6cff3770827037314eae9e46c9e 100644 (file)
@@ -1273,6 +1273,11 @@ 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 a4cefc532804b9d00a71f4d96cf2693e928cdc85..4965c4277dba73c6f47558a046a554bad8104510 100644 (file)
@@ -75,15 +75,21 @@ 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(metaclass=abc.ABCMeta):
@@ -92,22 +98,29 @@ 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):
             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 TestABC(unittest.TestCase):
         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):
index c7de97c73192ce4bd46a0225377965c1a0e41015..b671cbc12d5fdb7a0d3df011060d59d2d854cdd6 100644 (file)
@@ -582,12 +582,18 @@ 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 <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):
index 901c32655d14cce4a56f8fd42d71713082c6b555..17cd5d32ede21337396b9cfbb77db715ddda53ad 100644 (file)
@@ -33,26 +33,39 @@ 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 test_main():
index 2d91cb1e01f1863e61c93edfefcf067df718a9d3..e001936c55b99ee1895a4be65260416913a2a6bb 100644 (file)
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,13 @@ What's New in Python 3.0 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.
+
 - Issue #3663: Py_None was decref'd when printing SyntaxErrors.
 
 - Issue #3657: Fix uninitialized memory read when pickling longs.
index 8f7083d72d95cd36bdcfc939ab5e6ea972331c9d..ac61011c82025dda665b911e1c285a47c8647ead 100644 (file)
@@ -2474,39 +2474,38 @@ 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
@@ -2524,7 +2523,7 @@ 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;
@@ -2553,25 +2552,6 @@ 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,"
@@ -2601,6 +2581,24 @@ 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 = PyUnicode_InternFromString("__instancecheck__");
                if (name == NULL)
@@ -2625,51 +2623,25 @@ 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 (!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);
+       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;
 
-       return retval;
+       return abstract_issubclass(derived, cls);
 }
 
 int
@@ -2678,20 +2650,40 @@ 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 = 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 @@ 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 616164e1ce7475ca291918b8e4ceeca5f049a978..8f1b3892ac588d163cdae6da575884aca388e23a 100644 (file)
@@ -584,6 +584,49 @@ 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},
@@ -592,6 +635,8 @@ 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 9c9eb2f2b21ffe6094a79bc734f08b9adcb1b1d1..d7aac6d504182ac15bfe8127827d9070faa76808 100644 (file)
@@ -160,11 +160,12 @@ PyErr_GivenExceptionMatches(PyObject *err, PyObject *exc)
                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);