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Issue #2534: speed up isinstance() and issubclass() by 50-70%, so as to

Browse source 
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.
This commit is contained in:
Antoine Pitrou 2008-08-26 22:42:08 +00:00
parent 14cb6bcf2b
commit 0668c62677
8 changed files with 211 additions and 88 deletions
Download patch file Download diff file Expand all files Collapse all files

173
Objects/abstract.c
View 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);
for (i = 0; i < n; i++) {
if (derived == PyTuple_GET_ITEM(cls, i))
return 1;
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++) {
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);
}