/* This function is called by the tp_dealloc handler to clear weak references.
 *
 * This iterates through the weak references for 'object' and calls callbacks
 * for those references which have one.  It returns when all callbacks have
 * been attempted.
 */
void
PyObject_ClearWeakRefs(PyObject *object)
{
    PyWeakReference **list;

    if (object == NULL
        || !PyType_SUPPORTS_WEAKREFS(Py_TYPE(object))
        || object->ob_refcnt != 0) {
        PyErr_BadInternalCall();
        return;
    }
    list = GET_WEAKREFS_LISTPTR(object);
    /* 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) {
        PyWeakReference *current = *list;
        Py_ssize_t count = _PyWeakref_GetWeakrefCount(current);
        int restore_error = PyErr_Occurred() ? 1 : 0;
        PyObject *err_type    = NULL,
                 *err_value   = NULL,
                 *err_tb      = NULL;

        if (restore_error)
            PyErr_Fetch(&err_type, &err_value, &err_tb);
        if (count == 1) {
            PyObject *callback = current->wr_callback;

            current->wr_callback = NULL;
            clear_weakref(current);
            if (callback != NULL) {
                if (current->ob_refcnt > 0)
                    handle_callback(current, callback);
                Py_DECREF(callback);
            }
        }
        else {
            PyObject *tuple;
            Py_ssize_t i = 0;

            tuple = PyTuple_New(count * 2);
            if (tuple == NULL) {
                if (restore_error)
                    PyErr_Fetch(&err_type, &err_value, &err_tb);
                return;
            }

            for (i = 0; i < count; ++i) {
                PyWeakReference *next = current->wr_next;

                if (current->ob_refcnt > 0)
                {
                    Py_INCREF(current);
                    PyTuple_SET_ITEM(tuple, i * 2, (PyObject *) current);
                    PyTuple_SET_ITEM(tuple, i * 2 + 1, current->wr_callback);
                }
                else {
                    Py_DECREF(current->wr_callback);
                }
                current->wr_callback = NULL;
                clear_weakref(current);
                current = next;
            }
            for (i = 0; i < count; ++i) {
                PyObject *callback = PyTuple_GET_ITEM(tuple, i * 2 + 1);

                /* The tuple may have slots left to NULL */
                if (callback != NULL) {
                    PyObject *item = PyTuple_GET_ITEM(tuple, i * 2);
                    handle_callback((PyWeakReference *)item, callback);
                }
            }
            Py_DECREF(tuple);
        }
        if (restore_error)
            PyErr_Restore(err_type, err_value, err_tb);
    }
}
Exemple #2
0
/* This function is called by the tp_dealloc handler to clear weak references.
 *
 * This iterates through the weak references for 'object' and calls callbacks
 * for those references which have one.  It returns when all callbacks have
 * been attempted.
 */
void
PyObject_ClearWeakRefs(PyObject *object)
{
    PyWeakReference **list;

    if (object == NULL
        || !PyType_SUPPORTS_WEAKREFS(Py_TYPE(object))
        //|| object->ob_refcnt != 0
        ) {
        PyErr_BadInternalCall();
        return;
    }
    list = GET_WEAKREFS_LISTPTR(object);
    /* 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) {
        PyWeakReference *current = *list;
        Py_ssize_t count = _PyWeakref_GetWeakrefCount(current);
        int restore_error = PyErr_Occurred() ? 1 : 0;
        PyObject *err_type, *err_value, *err_tb;

        if (restore_error)
            PyErr_Fetch(&err_type, &err_value, &err_tb);
        if (count == 1) {
            PyObject *callback = current->wr_callback;

            current->wr_callback = NULL;
            clear_weakref(current);
            if (callback != NULL) {
                // Pyston change:
                // current is a stack reference to a GC allocated object.  If it wasn't null when we fetched it from *list, it won't
                // be collected, and we can trust that it's still valid here.
                if (1 /*current->ob_refcnt > 0*/)
                    handle_callback(current, callback);
                Py_DECREF(callback);
            }
        }
        else {
            PyObject *tuple;
            Py_ssize_t i = 0;

            tuple = PyTuple_New(count * 2);
            if (tuple == NULL) {
                if (restore_error)
                    PyErr_Fetch(&err_type, &err_value, &err_tb);
                return;
            }

            for (i = 0; i < count; ++i) {
                PyWeakReference *next = current->wr_next;

                // Pyston change:
                // current is a stack reference to a GC allocated object.  If it wasn't null when we fetched it from *list, it won't
                // be collected, and we can trust that it's still valid here.
                if (1 /*current->ob_refcnt > 0*/)
                {
                    Py_INCREF(current);
                    PyTuple_SET_ITEM(tuple, i * 2, (PyObject *) current);
                    PyTuple_SET_ITEM(tuple, i * 2 + 1, current->wr_callback);
                }
                else {
                    Py_DECREF(current->wr_callback);
                }
                current->wr_callback = NULL;
                clear_weakref(current);
                current = next;
            }
            for (i = 0; i < count; ++i) {
                PyObject *callback = PyTuple_GET_ITEM(tuple, i * 2 + 1);

                /* The tuple may have slots left to NULL */
                if (callback != NULL) {
                    PyObject *item = PyTuple_GET_ITEM(tuple, i * 2);
                    handle_callback((PyWeakReference *)item, callback);
                }
            }
            Py_DECREF(tuple);
        }
        if (restore_error)
            PyErr_Restore(err_type, err_value, err_tb);
    }
}