[Python-checkins] CVS: python/dist/src/Objects abstract.c,2.83,2.84

[Guido van Rossum]

Update of /cvsroot/python/python/dist/src/Objects
In directory usw-pr-cvs1:/tmp/cvs-serv13774

Modified Files:
	abstract.c 
Log Message:
Implement isinstance(x, (A, B, ...)).  Note that we only allow tuples,
not other sequences (then we'd have to except strings, and we'd still
be susceptible to recursive attacks).


Index: abstract.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Objects/abstract.c,v
retrieving revision 2.83
retrieving revision 2.84
diff -C2 -d -r2.83 -r2.84
*** abstract.c	2001/10/01 17:10:18	2.83
--- abstract.c	2001/10/07 20:53:45	2.84
***************
*** 1806,1809 ****
--- 1806,1823 ----
  		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) {
***************
*** 1828,1832 ****
  	if (retval < 0) {
  		PyErr_SetString(PyExc_TypeError,
! 				"isinstance() arg 2 must be a class or type");
  	}
  	return retval;
--- 1842,1847 ----
  	if (retval < 0) {
  		PyErr_SetString(PyExc_TypeError,
! 				"isinstance() arg 2 must be a class or type "
! 				"or tuple of those");
  	}
  	return retval;