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Implement isinstance(x, (A, B, ...)). Note that we only allow tuples,

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not other sequences (then we'd have to except strings, and we'd still
be susceptible to recursive attacks).
This commit is contained in:
Guido van Rossum 2001-10-07 20:54:12 +00:00
parent 1f733baa04
commit 03290ecbf1
2 changed files with 20 additions and 3 deletions
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17
Objects/abstract.c
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@ -1805,6 +1805,20 @@ PyObject_IsInstance(PyObject *inst, PyObject *cls)
else if (PyType_Check(cls)) {
retval = PyObject_TypeCheck(inst, (PyTypeObject *)cls);
}
else if (PyTuple_Check(cls)) {
/* Not a general sequence -- that opens up the road to
recursion and stack overflow. */
int i, n;
n = PyTuple_GET_SIZE(cls);
for (i = 0; i < n; i++) {
retval = PyObject_IsInstance(
inst, PyTuple_GET_ITEM(cls, i));
if (retval != 0)
break;
}
return retval;
}
else if (!PyInstance_Check(inst)) {
if (__class__ == NULL) {
__class__ = PyString_FromString("__class__");
@ -1827,7 +1841,8 @@ PyObject_IsInstance(PyObject *inst, PyObject *cls)
if (retval < 0) {
PyErr_SetString(PyExc_TypeError,
"isinstance() arg 2 must be a class or type");
"isinstance() arg 2 must be a class or type "
"or tuple of those");
}
return retval;
}