vlc_object_internals_t *next; /* next sibling */
vlc_object_internals_t *prev; /* previous sibling */
vlc_object_internals_t *first; /* first child */
+ vlc_object_t *old_parent;
};
#define ZOOM_SECTION N_("Zoom")
p_priv->b_thread = false;
p_new->p_parent = NULL;
p_priv->first = NULL;
+#ifndef NDEBUG
+ p_priv->old_parent = NULL;
+#endif
/* Initialize mutexes and condvars */
vlc_mutex_init( &p_priv->var_lock );
priv->prev = NULL;
vlc_object_hold (p_parent);
libvlc_lock (p_this->p_libvlc);
+#ifndef NDEBUG
+ /* Reparenting an object carries a risk of invalid access to the parent,
+ * from another thread. This can happen when inheriting a variable, or
+ * through any direct access to vlc_object_t.p_parent. Also, reparenting
+ * brings a functional bug, whereby the reparented object uses incorrect
+ * old values for inherited variables (as the new parent may have different
+ * variable values, especially if it is an input).
+ * Note that the old parent may be already destroyed.
+ * So its pointer must not be dereferenced.
+ */
+ if (priv->old_parent)
+ msg_Info (p_this, "Reparenting an object is dangerous (%p -> %p)!",
+ priv->old_parent, p_parent);
+#endif
/* Attach the parent to its child */
assert (!p_this->p_parent);
priv->next->prev = priv->prev;
/* Remove p_this's parent */
+#ifndef NDEBUG
+ priv->old_parent = p_this->p_parent;
+#endif
p_this->p_parent = NULL;
}