properly lookup __instancecheck__ and __subclasscheck__

This commit is contained in:
Benjamin Peterson 2009-05-16 21:44:25 +00:00
parent 757b3c90e6
commit fb6fb062e8
3 changed files with 46 additions and 36 deletions

View File

@ -1683,16 +1683,25 @@ order (MRO) for bases """
return 0
def stop(self):
raise StopIteration
def return_true(self, thing=None):
return True
def do_isinstance(obj):
return isinstance(int, obj)
def do_issubclass(obj):
return issubclass(int, obj)
# It would be nice to have every special method tested here, but I'm
# only listing the ones I can remember outside of typeobject.c, since it
# does it right.
specials = [
("__unicode__", unicode, hello, {}),
("__reversed__", reversed, empty_seq, {}),
("__length_hint__", list, zero,
("__unicode__", unicode, hello, set(), {}),
("__reversed__", reversed, empty_seq, set(), {}),
("__length_hint__", list, zero, set(),
{"__iter__" : iden, "next" : stop}),
("__sizeof__", sys.getsizeof, zero, {}),
("__sizeof__", sys.getsizeof, zero, set(), {}),
("__instancecheck__", do_isinstance, return_true, set(), {}),
("__subclasscheck__", do_issubclass, return_true,
set(("__bases__",)), {}),
# These two fail because the compiler generates LOAD_ATTR to look
# them up. We'd have to add a new opcode to fix this, and it's
# probably not worth it.
@ -1704,7 +1713,9 @@ order (MRO) for bases """
def __getattr__(self, attr, test=self):
test.fail("__getattr__ called with {0}".format(attr))
def __getattribute__(self, attr, test=self):
test.fail("__getattribute__ called with {0}".format(attr))
if attr not in ok:
test.fail("__getattribute__ called with {0}".format(attr))
return object.__getattribute__(attr)
class SpecialDescr(object):
def __init__(self, impl):
self.impl = impl
@ -1713,7 +1724,7 @@ order (MRO) for bases """
return self.impl.__get__(obj, owner)
for name, runner, meth_impl, env in specials:
for name, runner, meth_impl, ok, env in specials:
class X(Checker):
pass
for attr, obj in env.iteritems():

View File

@ -2926,14 +2926,19 @@ PyObject_IsInstance(PyObject *inst, PyObject *cls)
Py_LeaveRecursiveCall();
return r;
}
if (name == NULL) {
name = PyString_InternFromString("__instancecheck__");
if (name == NULL)
return -1;
if (PyInstance_Check(cls)) {
checker = PyObject_GetAttrString(cls, "__instancecheck__");
if (checker == NULL) {
if (PyErr_ExceptionMatches(PyExc_AttributeError))
PyErr_Clear();
else
return -1;
}
}
else {
checker = _PyObject_LookupSpecial(cls, "__instancecheck__", &name);
}
checker = PyObject_GetAttr(cls, name);
if (checker == NULL && PyErr_Occurred())
PyErr_Clear();
if (checker != NULL) {
PyObject *res;
int ok = -1;
@ -3008,14 +3013,21 @@ PyObject_IsSubclass(PyObject *derived, PyObject *cls)
Py_LeaveRecursiveCall();
return r;
}
if (name == NULL) {
name = PyString_InternFromString("__subclasscheck__");
if (name == NULL)
if (PyInstance_Check(cls)) {
PyErr_Fetch(&t, &v, &tb);
checker = PyObject_GetAttr(cls, name);
if (checker == NULL &&
!PyErr_ExceptionMatches(PyExc_AttributeError)) {
Py_XDECREF(t);
Py_XDECREF(v);
Py_XDECREF(tb);
return -1;
}
PyErr_Restore(t, v, tb);
}
else {
checker = _PyObject_LookupSpecial(cls, "__subclasscheck__", &name);
}
PyErr_Fetch(&t, &v, &tb);
checker = PyObject_GetAttr(cls, name);
PyErr_Restore(t, v, tb);
if (checker != NULL) {
PyObject *res;
int ok = -1;

View File

@ -585,14 +585,6 @@ type___instancecheck__(PyObject *type, PyObject *inst)
}
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)
{
@ -606,13 +598,6 @@ type___subclasscheck__(PyObject *type, PyObject *inst)
}
}
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},
@ -622,8 +607,6 @@ 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}
};
@ -2674,6 +2657,10 @@ static PyMethodDef type_methods[] = {
PyDoc_STR("mro() -> list\nreturn a type's method resolution order")},
{"__subclasses__", (PyCFunction)type_subclasses, METH_NOARGS,
PyDoc_STR("__subclasses__() -> list of immediate subclasses")},
{"__instancecheck__", type___instancecheck__, METH_O,
PyDoc_STR("__instancecheck__() -> check if an object is an instance")},
{"__subclasscheck__", type___subclasscheck__, METH_O,
PyDoc_STR("__subclasschck__ -> check if an class is a subclass")},
{0}
};