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Move the code implementing isinstance() and issubclass() to new C

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APIs, PyObject_IsInstance() and PyObject_IsSubclass() -- both
returning an int, or -1 for errors.
This commit is contained in:
Guido van Rossum 2001-03-21 18:40:58 +00:00
parent 91751143eb
commit 823649d544
3 changed files with 125 additions and 96 deletions
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112
Objects/abstract.c
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@ -1626,3 +1626,115 @@ PyObject_CallMethod(PyObject *o, char *name, char *format, ...)
return retval;
}
/* isinstance(), issubclass() */
static int
abstract_issubclass(PyObject *derived, PyObject *cls, int first)
{
static PyObject *__bases__ = NULL;
PyObject *bases;
int i, n;
int r = 0;
if (__bases__ == NULL) {
__bases__ = PyString_FromString("__bases__");
if (__bases__ == NULL)
return -1;
}
if (first) {
bases = PyObject_GetAttr(cls, __bases__);
if (bases == NULL || !PyTuple_Check(bases)) {
Py_XDECREF(bases);
PyErr_SetString(PyExc_TypeError,
"issubclass() arg 2 must be a class");
return -1;
}
Py_DECREF(bases);
}
if (derived == cls)
return 1;
bases = PyObject_GetAttr(derived, __bases__);
if (bases == NULL || !PyTuple_Check(bases)) {
Py_XDECREF(bases);
PyErr_SetString(PyExc_TypeError,
"issubclass() arg 1 must be a class");
return -1;
}
n = PyTuple_GET_SIZE(bases);
for (i = 0; i < n; i++) {
r = abstract_issubclass(PyTuple_GET_ITEM(bases, i), cls, 0);
if (r != 0)
break;
}
Py_DECREF(bases);
return r;
}
int
PyObject_IsInstance(PyObject *inst, PyObject *cls)
{
PyObject *icls;
static PyObject *__class__ = NULL;
int retval = 0;
if (PyClass_Check(cls)) {
if (PyInstance_Check(inst)) {
PyObject *inclass =
(PyObject*)((PyInstanceObject*)inst)->in_class;
retval = PyClass_IsSubclass(inclass, cls);
}
}
else if (PyType_Check(cls)) {
retval = ((PyObject *)(inst->ob_type) == cls);
}
else if (!PyInstance_Check(inst)) {
if (__class__ == NULL) {
__class__ = PyString_FromString("__class__");
if (__class__ == NULL)
return -1;
}
icls = PyObject_GetAttr(inst, __class__);
if (icls != NULL) {
retval = abstract_issubclass(icls, cls, 1);
Py_DECREF(icls);
if (retval < 0 &&
!PyErr_ExceptionMatches(PyExc_TypeError))
return -1;
}
else
retval = -1;
}
else
retval = -1;
if (retval < 0) {
PyErr_SetString(PyExc_TypeError,
"isinstance() arg 2 must be a class or type");
}
return retval;
}
int
PyObject_IsSubclass(PyObject *derived, PyObject *cls)
{
int retval;
if (!PyClass_Check(derived) || !PyClass_Check(cls)) {
retval = abstract_issubclass(derived, cls, 1);
}
else {
/* shortcut */
if (!(retval = (derived == cls)))
retval = PyClass_IsSubclass(derived, cls);
}
return retval;
}