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cleanup_helper(): Make sure we invalidate all reference objects

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before calling any callbacks.  This is important
                   since the callback objects only look at themselves
                   to determine that they are invalide.  This change
                   avoids a segfault when callbacks use a different
                   reference to an object in the process of being
                   deallocated.

This fixes SF bug #415660.
This commit is contained in:
Fred Drake 2001-04-13 17:15:47 +00:00
parent eb0d992520
commit 2a5a5ca012
1 changed files with 41 additions and 6 deletions
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47
Modules/_weakref.c
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@ -740,15 +740,22 @@ cleanup_helper(PyObject *object)
return;
}
list = GET_WEAKREFS_LISTPTR(object);
while (*list != NULL) {
PyWeakReference *current = *list;
PyObject *callback = current->wr_callback;
/* Remove the callback-less basic and proxy references */
if (*list != NULL && (*list)->wr_callback == NULL) {
clear_weakref(*list);
if (*list != NULL && (*list)->wr_callback == NULL)
clear_weakref(*list);
}
if (*list != NULL) {
int count = getweakrefcount(*list);
Py_XINCREF(callback);
clear_weakref(current);
if (callback != NULL) {
if (count == 1) {
PyWeakReference *current = *list;
PyObject *callback = current->wr_callback;
PyObject *cbresult;
Py_INCREF(callback);
clear_weakref(current);
cbresult = PyObject_CallFunction(callback, "O", current);
if (cbresult == NULL)
PyErr_WriteUnraisable(callback);
@ -756,6 +763,34 @@ cleanup_helper(PyObject *object)
Py_DECREF(cbresult);
Py_DECREF(callback);
}
else {
PyObject *tuple = PyTuple_New(count * 2);
PyWeakReference *current = *list;
int i = 0;
for (i = 0; i < count; ++i) {
PyWeakReference *next = current->wr_next;
Py_INCREF(current);
PyTuple_SET_ITEM(tuple, i * 2, (PyObject *) current);
PyTuple_SET_ITEM(tuple, i * 2 + 1, current->wr_callback);
current->wr_callback = NULL;
next = current->wr_next;
clear_weakref(current);
current = next;
}
for (i = 0; i < count; ++i) {
PyObject *current = PyTuple_GET_ITEM(tuple, i * 2);
PyObject *callback = PyTuple_GET_ITEM(tuple, i * 2 + 1);
PyObject *cbresult = PyObject_CallFunction(callback, "O",
current);
if (cbresult == NULL)
PyErr_WriteUnraisable(callback);
else
Py_DECREF(cbresult);
}
Py_DECREF(tuple);
}
}
return;
}