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Be more careful about maintaining the invariants; it was actually

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possible that the callback-less flavors of the ref or proxy could have
been added during GC, so we don't want to replace them.
This commit is contained in:
Fred Drake 2004-08-03 14:47:25 +00:00
parent 43220ea26e
commit 6d3265dab6
1 changed files with 25 additions and 3 deletions
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28
Objects/weakrefobject.c
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@ -747,13 +747,23 @@ PyWeakref_NewRef(PyObject *ob, PyObject *callback)
them. */
result = new_weakref(ob, callback);
if (result != NULL) {
get_basic_refs(*list, &ref, &proxy);
if (callback == NULL) {
insert_head(result, list);
if (ref == NULL)
insert_head(result, list);
else {
/* Someone else added a ref without a callback
during GC. Return that one instead of this one
to avoid violating the invariants of the list
of weakrefs for ob. */
Py_DECREF(result);
Py_INCREF(ref);
result = ref;
}
}
else {
PyWeakReference *prev;
get_basic_refs(*list, &ref, &proxy);
prev = (proxy == NULL) ? ref : proxy;
if (prev == NULL)
insert_head(result, list);
@ -803,8 +813,18 @@ PyWeakref_NewProxy(PyObject *ob, PyObject *callback)
else
result->ob_type = &_PyWeakref_ProxyType;
get_basic_refs(*list, &ref, &proxy);
if (callback == NULL)
if (callback == NULL) {
if (proxy != NULL) {
/* Someone else added a proxy without a callback
during GC. Return that one instead of this one
to avoid violating the invariants of the list
of weakrefs for ob. */
Py_DECREF(result);
Py_INCREF(result = proxy);
goto skip_insert;
}
prev = ref;
}
else
prev = (proxy == NULL) ? ref : proxy;
@ -812,6 +832,8 @@ PyWeakref_NewProxy(PyObject *ob, PyObject *callback)
insert_head(result, list);
else
insert_after(result, prev);
skip_insert:
;
}
}
return (PyObject *) result;