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Add Garbage Collection support to new-style classes (not yet to their

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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.)
This commit is contained in:
Guido van Rossum 2001-10-02 21:24:57 +00:00
parent 0481d24dd5
commit 048eb75c2d
5 changed files with 237 additions and 39 deletions
Download patch file Download diff file Expand all files Collapse all files

114
Objects/descrobject.c
View file

@ -38,9 +38,10 @@ typedef struct {
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 @@ static PyGetSetDef wrapper_getset[] = {
{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 @@ static PyTypeObject PyMethodDescr_Type = {
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 @@ static PyTypeObject PyMemberDescr_Type = {
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 @@ static PyTypeObject PyGetSetDescr_Type = {
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 @@ static PyTypeObject PyWrapperDescr_Type = {
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 PyMethodDef proxy_methods[] = {
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 @@ proxy_str(proxyobject *pp)
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 @@ PyTypeObject proxytype = {
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 @@ PyDictProxy_New(PyObject *dict)
{
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 @@ typedef struct {
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 @@ wrapper_call(wrapperobject *wp, PyObject *args, PyObject *kwds)
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 @@ PyTypeObject wrappertype = {
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 @@ PyWrapper_New(PyObject *d, PyObject *self)
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 @@ property_dealloc(PyObject *self)
{
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 @@ static char property_doc[] =
" 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 @@ PyTypeObject PyProperty_Type = {
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 @@ PyTypeObject PyProperty_Type = {
property_init, /* tp_init */
PyType_GenericAlloc, /* tp_alloc */
PyType_GenericNew, /* tp_new */
_PyObject_Del, /* tp_free */
_PyObject_GC_Del, /* tp_free */
};