Add Garbage Collection support to new-style classes (not yet to their
instances).
Also added GC support to various auxiliary types: super, property,
descriptors, wrappers, dictproxy. (Only type objects have a tp_clear
field; the other types are.)
One change was necessary to the GC infrastructure. We have statically
allocated type objects that don't have a GC header (and can't easily
be given one) and heap-allocated type objects that do have a GC
header. Giving these different metatypes would be really ugly: I
tried, and I had to modify pickle.py, cPickle.c, copy.py, add a new
invent a new name for the new metatype and make it a built-in, change
affected tests... In short, a mess. So instead, we add a new type
slot tp_is_gc, which is a simple Boolean function that determines
whether a particular instance has GC headers or not. This slot is
only relevant for types that have the (new) GC flag bit set. If the
tp_is_gc slot is NULL (by far the most common case), all instances of
the type are deemed to have GC headers. This slot is called by the
PyObject_IS_GC() macro (which is only used twice, both times in
gcmodule.c).
I also changed the extern declarations for a bunch of GC-related
functions (_PyObject_GC_Del etc.): these always exist but objimpl.h
only declared them when WITH_CYCLE_GC was defined, but I needed to be
able to reference them without #ifdefs. (When WITH_CYCLE_GC is not
defined, they do the same as their non-GC counterparts anyway.)
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index fea67f3..3a65902 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -38,9 +38,10 @@
static void
descr_dealloc(PyDescrObject *descr)
{
+ _PyObject_GC_UNTRACK(descr);
Py_XDECREF(descr->d_type);
Py_XDECREF(descr->d_name);
- PyObject_DEL(descr);
+ PyObject_GC_Del(descr);
}
static char *
@@ -352,6 +353,20 @@
{0}
};
+static int
+descr_traverse(PyObject *self, visitproc visit, void *arg)
+{
+ PyDescrObject *descr = (PyDescrObject *)self;
+ int err;
+
+ if (descr->d_type) {
+ err = visit((PyObject *)(descr->d_type), arg);
+ if (err)
+ return err;
+ }
+ return 0;
+}
+
static PyTypeObject PyMethodDescr_Type = {
PyObject_HEAD_INIT(&PyType_Type)
0,
@@ -373,9 +388,9 @@
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
- Py_TPFLAGS_DEFAULT, /* tp_flags */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
0, /* tp_doc */
- 0, /* tp_traverse */
+ descr_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
@@ -411,9 +426,9 @@
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
- Py_TPFLAGS_DEFAULT, /* tp_flags */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
0, /* tp_doc */
- 0, /* tp_traverse */
+ descr_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
@@ -449,9 +464,9 @@
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
- Py_TPFLAGS_DEFAULT, /* tp_flags */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
0, /* tp_doc */
- 0, /* tp_traverse */
+ descr_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
@@ -487,9 +502,9 @@
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
- Py_TPFLAGS_DEFAULT, /* tp_flags */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
0, /* tp_doc */
- 0, /* tp_traverse */
+ descr_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
@@ -679,8 +694,9 @@
static void
proxy_dealloc(proxyobject *pp)
{
+ _PyObject_GC_UNTRACK(pp);
Py_DECREF(pp->dict);
- PyObject_DEL(pp);
+ PyObject_GC_Del(pp);
}
static PyObject *
@@ -695,6 +711,20 @@
return PyObject_Str(pp->dict);
}
+static int
+proxy_traverse(PyObject *self, visitproc visit, void *arg)
+{
+ proxyobject *pp = (proxyobject *)self;
+ int err;
+
+ if (pp->dict) {
+ err = visit(pp->dict, arg);
+ if (err)
+ return err;
+ }
+ return 0;
+}
+
PyTypeObject proxytype = {
PyObject_HEAD_INIT(&PyType_Type)
0, /* ob_size */
@@ -717,9 +747,9 @@
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
- Py_TPFLAGS_DEFAULT, /* tp_flags */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
0, /* tp_doc */
- 0, /* tp_traverse */
+ proxy_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
@@ -739,10 +769,11 @@
{
proxyobject *pp;
- pp = PyObject_NEW(proxyobject, &proxytype);
+ pp = PyObject_GC_New(proxyobject, &proxytype);
if (pp != NULL) {
Py_INCREF(dict);
pp->dict = dict;
+ _PyObject_GC_TRACK(pp);
}
return (PyObject *)pp;
}
@@ -762,9 +793,10 @@
static void
wrapper_dealloc(wrapperobject *wp)
{
+ _PyObject_GC_UNTRACK(wp);
Py_XDECREF(wp->descr);
Py_XDECREF(wp->self);
- PyObject_DEL(wp);
+ PyObject_GC_Del(wp);
}
static PyMethodDef wrapper_methods[] = {
@@ -808,6 +840,25 @@
return (*wrapper)(self, args, wp->descr->d_wrapped);
}
+static int
+wrapper_traverse(PyObject *self, visitproc visit, void *arg)
+{
+ wrapperobject *wp = (wrapperobject *)self;
+ int err;
+
+ if (wp->descr) {
+ err = visit((PyObject *)(wp->descr), arg);
+ if (err)
+ return err;
+ }
+ if (wp->self) {
+ err = visit(wp->self, arg);
+ if (err)
+ return err;
+ }
+ return 0;
+}
+
PyTypeObject wrappertype = {
PyObject_HEAD_INIT(&PyType_Type)
0, /* ob_size */
@@ -830,9 +881,9 @@
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
- Py_TPFLAGS_DEFAULT, /* tp_flags */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
0, /* tp_doc */
- 0, /* tp_traverse */
+ wrapper_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
@@ -857,12 +908,13 @@
descr = (PyWrapperDescrObject *)d;
assert(PyObject_IsInstance(self, (PyObject *)(descr->d_type)));
- wp = PyObject_NEW(wrapperobject, &wrappertype);
+ wp = PyObject_GC_New(wrapperobject, &wrappertype);
if (wp != NULL) {
Py_INCREF(descr);
wp->descr = descr;
Py_INCREF(self);
wp->self = self;
+ _PyObject_GC_TRACK(wp);
}
return (PyObject *)wp;
}
@@ -919,6 +971,7 @@
{
propertyobject *gs = (propertyobject *)self;
+ _PyObject_GC_UNTRACK(self);
Py_XDECREF(gs->prop_get);
Py_XDECREF(gs->prop_set);
Py_XDECREF(gs->prop_del);
@@ -1012,6 +1065,26 @@
" def delx(self): del self.__x\n"
" x = property(getx, setx, delx, \"I'm the 'x' property.\")";
+static int
+property_traverse(PyObject *self, visitproc visit, void *arg)
+{
+ propertyobject *pp = (propertyobject *)self;
+ int err;
+
+#define VISIT(SLOT) \
+ if (pp->SLOT) { \
+ err = visit((PyObject *)(pp->SLOT), arg); \
+ if (err) \
+ return err; \
+ }
+
+ VISIT(prop_get);
+ VISIT(prop_set);
+ VISIT(prop_del);
+
+ return 0;
+}
+
PyTypeObject PyProperty_Type = {
PyObject_HEAD_INIT(&PyType_Type)
0, /* ob_size */
@@ -1034,9 +1107,10 @@
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
- Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
+ Py_TPFLAGS_BASETYPE, /* tp_flags */
property_doc, /* tp_doc */
- 0, /* tp_traverse */
+ property_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
@@ -1053,5 +1127,5 @@
property_init, /* tp_init */
PyType_GenericAlloc, /* tp_alloc */
PyType_GenericNew, /* tp_new */
- _PyObject_Del, /* tp_free */
+ _PyObject_GC_Del, /* tp_free */
};