Another step in the right direction: when a new class's attribute
corresponding to a dispatch slot (e.g. __getitem__ or __add__) is set,
calculate the proper dispatch slot and propagate the change to all
subclasses. Because of multiple inheritance, there's no easy way to
avoid always recursing down the tree of subclasses. Who cares?
(There's more to do, but this works. There's also a test for this now.)
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index 50e7d9d..1768a6d 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -7,6 +7,10 @@
if not (a == b):
raise TestFailed, "%r == %r" % (a, b)
+def veris(a, b):
+ if a is not b:
+ raise TestFailed, "%r is %r" % (a, b)
+
def testunop(a, res, expr="len(a)", meth="__len__"):
if verbose: print "checking", expr
dict = {'a': a}
@@ -623,10 +627,8 @@
class autosuper(type):
# Automatically add __super to the class
# This trick only works for dynamic classes
- # so we force __dynamic__ = 1
def __new__(metaclass, name, bases, dict):
- # XXX Should check that name isn't already a base class name
- dict["__dynamic__"] = 1
+ assert dict.get("__dynamic__", 1)
cls = super(autosuper, metaclass).__new__(metaclass,
name, bases, dict)
# Name mangling for __super removes leading underscores
@@ -949,7 +951,7 @@
# Test handling of int*seq and seq*int
class I(int):
- __dynamic__ = 1
+ __dynamic__ = 1 # XXX why?
vereq("a"*I(2), "aa")
vereq(I(2)*"a", "aa")
vereq(2*I(3), 6)
@@ -958,7 +960,7 @@
# Test handling of long*seq and seq*long
class L(long):
- __dynamic__ = 1
+ __dynamic__ = 1 # XXX why?
vereq("a"*L(2L), "aa")
vereq(L(2L)*"a", "aa")
vereq(2*L(3), 6)
@@ -967,7 +969,7 @@
# Test comparison of classes with dynamic metaclasses
class dynamicmetaclass(type):
- __dynamic__ = 1
+ __dynamic__ = 1 # XXX ???
class someclass:
__metaclass__ = dynamicmetaclass
verify(someclass != object)
@@ -1253,7 +1255,7 @@
verify(10 not in c1)
# Test the default behavior for dynamic classes
class D(object):
- __dynamic__ = 1
+ __dynamic__ = 1 # XXX why?
def __getitem__(self, i):
if 0 <= i < 10: return i
raise IndexError
@@ -1563,30 +1565,30 @@
verify((+a).__class__ is float)
class madcomplex(complex):
- __dynamic__ = 0
+ __dynamic__ = 0 # XXX Shouldn't be necessary
def __repr__(self):
return "%.17gj%+.17g" % (self.imag, self.real)
a = madcomplex(-3, 4)
vereq(repr(a), "4j-3")
base = complex(-3, 4)
- verify(base.__class__ is complex)
+ veris(base.__class__, complex)
vereq(a, base)
vereq(complex(a), base)
- verify(complex(a).__class__ is complex)
+ veris(complex(a).__class__, complex)
a = madcomplex(a) # just trying another form of the constructor
vereq(repr(a), "4j-3")
vereq(a, base)
vereq(complex(a), base)
- verify(complex(a).__class__ is complex)
+ veris(complex(a).__class__, complex)
vereq(hash(a), hash(base))
- verify((+a).__class__ is complex)
- verify((a + 0).__class__ is complex)
+ veris((+a).__class__, complex)
+ veris((a + 0).__class__, complex)
vereq(a + 0, base)
- verify((a - 0).__class__ is complex)
+ veris((a - 0).__class__, complex)
vereq(a - 0, base)
- verify((a * 1).__class__ is complex)
+ veris((a * 1).__class__, complex)
vereq(a * 1, base)
- verify((a / 1).__class__ is complex)
+ veris((a / 1).__class__, complex)
vereq(a / 1, base)
class madtuple(tuple):
@@ -2237,6 +2239,66 @@
def __eq__(self, other):
return self.lower() == other.lower()
+def subclasspropagation():
+ if verbose: print "Testing propagation of slot functions to subclasses..."
+ class A(object):
+ pass
+ class B(A):
+ pass
+ class C(A):
+ pass
+ class D(B, C):
+ pass
+ d = D()
+ vereq(hash(d), id(d))
+ A.__hash__ = lambda self: 42
+ vereq(hash(d), 42)
+ C.__hash__ = lambda self: 314
+ vereq(hash(d), 314)
+ B.__hash__ = lambda self: 144
+ vereq(hash(d), 144)
+ D.__hash__ = lambda self: 100
+ vereq(hash(d), 100)
+ del D.__hash__
+ vereq(hash(d), 144)
+ del B.__hash__
+ vereq(hash(d), 314)
+ del C.__hash__
+ vereq(hash(d), 42)
+ del A.__hash__
+ vereq(hash(d), id(d))
+ d.foo = 42
+ d.bar = 42
+ vereq(d.foo, 42)
+ vereq(d.bar, 42)
+ def __getattribute__(self, name):
+ if name == "foo":
+ return 24
+ return object.__getattribute__(self, name)
+ A.__getattribute__ = __getattribute__
+ vereq(d.foo, 24)
+ vereq(d.bar, 42)
+ def __getattr__(self, name):
+ if name in ("spam", "foo", "bar"):
+ return "hello"
+ raise AttributeError, name
+ B.__getattr__ = __getattr__
+ vereq(d.spam, "hello")
+ vereq(d.foo, 24)
+ vereq(d.bar, 42)
+ del A.__getattribute__
+ vereq(d.foo, 42)
+ del d.foo
+ vereq(d.foo, "hello")
+ vereq(d.bar, 42)
+ del B.__getattr__
+ try:
+ d.foo
+ except AttributeError:
+ pass
+ else:
+ raise TestFailed, "d.foo should be undefined now"
+
def test_main():
class_docstrings()
@@ -2284,6 +2346,7 @@
pickles()
copies()
binopoverride()
+ subclasspropagation()
if verbose: print "All OK"
if __name__ == "__main__":
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 1b51971..ced80ec 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -676,7 +676,7 @@
staticforward void object_dealloc(PyObject *);
staticforward int object_init(PyObject *, PyObject *, PyObject *);
-staticforward int update_slot(PyTypeObject *, PyObject *, PyObject *);
+staticforward int update_slot(PyTypeObject *, PyObject *);
staticforward void fixup_slot_dispatchers(PyTypeObject *);
static PyObject *
@@ -1107,7 +1107,7 @@
if (type->tp_flags & Py_TPFLAGS_DYNAMICTYPE) {
if (PyObject_GenericSetAttr((PyObject *)type, name, value) < 0)
return -1;
- return update_slot(type, name, value);
+ return update_slot(type, name);
}
PyErr_SetString(PyExc_TypeError, "can't set static type attributes");
return -1;
@@ -3679,6 +3679,7 @@
int offset;
void *function;
wrapperfunc wrapper;
+ PyObject *name_strobj;
} slotdef;
#undef TPSLOT
@@ -3797,9 +3798,7 @@
slot_nb_inplace_true_divide, wrap_binaryfunc),
TPSLOT("__str__", tp_str, slot_tp_str, wrap_unaryfunc),
- TPSLOT("__str__", tp_print, NULL, NULL),
TPSLOT("__repr__", tp_repr, slot_tp_repr, wrap_unaryfunc),
- TPSLOT("__repr__", tp_print, NULL, NULL),
TPSLOT("__cmp__", tp_compare, _PyObject_SlotCompare, wrap_cmpfunc),
TPSLOT("__hash__", tp_hash, slot_tp_hash, wrap_hashfunc),
TPSLOT("__call__", tp_call, slot_tp_call, wrap_call),
@@ -3827,35 +3826,6 @@
{NULL}
};
-static int
-update_slot(PyTypeObject *type, PyObject *name, PyObject *value)
-{
- char *s;
- int n;
- slotdef *p;
- void **ptr;
-
- assert(type->tp_flags & Py_TPFLAGS_HEAPTYPE);
- if (value == NULL)
- return 0; /* Can't unset a slot */
- s = PyString_AsString(name);
- n = PyString_Size(name);
- if (s == NULL || n < 0) {
- /* Shouldn't happen, but can't be bothered */
- PyErr_Clear();
- return 0;
- }
- if (!(s[0] == '_' && s[1] == '_' && s[n-1] == '_' && s[n-2] == '_'))
- return 0;
- for (p = slotdefs; p->name; p++) {
- if (!strcmp(p->name, s)) {
- ptr = (void **) ((char *)type + p->offset);
- *ptr = p->function;
- }
- }
- return 0;
-}
-
static void **
slotptr(PyTypeObject *type, int offset)
{
@@ -3883,6 +3853,119 @@
return (void **)ptr;
}
+staticforward int recurse_down_subclasses(PyTypeObject *type, int offset);
+
+static int
+update_one_slot(PyTypeObject *type, int offset)
+{
+ slotdef *p;
+ PyObject *descr;
+ PyWrapperDescrObject *d;
+ void *generic = NULL, *specific = NULL;
+ int use_generic = 0;
+ void **ptr;
+
+ for (p = slotdefs; p->name; p++) {
+ if (p->offset != offset)
+ continue;
+ descr = _PyType_Lookup(type, p->name_strobj);
+ if (descr == NULL)
+ continue;
+ ptr = slotptr(type, p->offset);
+ if (ptr == NULL)
+ continue;
+ generic = p->function;
+ if (descr->ob_type == &PyWrapperDescr_Type) {
+ d = (PyWrapperDescrObject *)descr;
+ if (d->d_base->wrapper == p->wrapper &&
+ PyType_IsSubtype(type, d->d_type)) {
+ if (specific == NULL ||
+ specific == d->d_wrapped)
+ specific = d->d_wrapped;
+ else
+ use_generic = 1;
+ }
+ }
+ else
+ use_generic = 1;
+ if (specific && !use_generic)
+ *ptr = specific;
+ else
+ *ptr = generic;
+ }
+ if (recurse_down_subclasses(type, offset) < 0)
+ return -1;
+ return 0;
+}
+
+static int
+recurse_down_subclasses(PyTypeObject *type, int offset)
+{
+ PyTypeObject *subclass;
+ PyObject *ref, *subclasses;
+ int i, n;
+
+ subclasses = type->tp_subclasses;
+ if (subclasses == NULL)
+ return 0;
+ assert(PyList_Check(subclasses));
+ n = PyList_GET_SIZE(subclasses);
+ for (i = 0; i < n; i++) {
+ ref = PyList_GET_ITEM(subclasses, i);
+ assert(PyWeakref_CheckRef(ref));
+ subclass = (PyTypeObject *)PyWeakref_GET_OBJECT(ref);
+ if (subclass == NULL)
+ continue;
+ assert(PyType_Check(subclass));
+ if (update_one_slot(subclass, offset) < 0)
+ return -1;
+ }
+ return 0;
+}
+
+static void
+init_name_strobj(void)
+{
+ slotdef *p;
+ static int initialized = 0;
+
+ if (initialized)
+ return;
+ for (p = slotdefs; p->name; p++) {
+ p->name_strobj = PyString_InternFromString(p->name);
+ if (!p->name_strobj)
+ Py_FatalError("XXX ouch");
+ }
+ initialized = 1;
+}
+
+static void
+collect_offsets(PyObject *name, int offsets[])
+{
+ slotdef *p;
+
+ init_name_strobj();
+ for (p = slotdefs; p->name; p++) {
+ if (name == p->name_strobj)
+ *offsets++ = p->offset;
+ }
+ *offsets = 0;
+}
+
+static int
+update_slot(PyTypeObject *type, PyObject *name)
+{
+ int offsets[10];
+ int *ip;
+
+ collect_offsets(name, offsets);
+ for (ip = offsets; *ip; ip++) {
+ if (update_one_slot(type, *ip) < 0)
+ return -1;
+ }
+ return 0;
+}
+
static void
fixup_slot_dispatchers(PyTypeObject *type)
{