list: don't multiple-evaluate arguments to tlist_top and tlist_tail

[ccan] / ccan / list / list.h

diff --git a/ccan/list/list.h b/ccan/list/list.h
index bda2922bc37b7b8dc22ec5482b5e6d75513c1eb7..1feb58919142fc3bbe6d0eee23418ca52c27c6e9 100644 (file)
--- a/ccan/list/list.h
+++ b/ccan/list/list.h
@@ -279,8 +279,15 @@ static inline void list_del_from(struct list_head *h, struct list_node *n)
  *     struct child *first;
  *     first = list_top(&parent->children, struct child, list);
  */
  *     struct child *first;
  *     first = list_top(&parent->children, struct child, list);
  */

-#define list_top(h, type, member) \
-       (list_empty(h) ? NULL : list_entry((h)->n.next, type, member))
+#define list_top(h, type, member)                                      \
+       ((type *)list_top_((h), container_off((h)->n.next, type, member)))
+
+static inline const void *list_top_(const struct list_head *h, size_t off)
+{
+       if (list_empty(h))
+               return NULL;
+       return (const char *)h->n.next - off;
+}

 
 /**
  * list_tail - get the last entry in a list
 
 /**
  * list_tail - get the last entry in a list


@@ -295,11 +302,18 @@ static inline void list_del_from(struct list_head *h, struct list_node *n)
  *     last = list_tail(&parent->children, struct child, list);
  */
 #define list_tail(h, type, member) \
  *     last = list_tail(&parent->children, struct child, list);
  */
 #define list_tail(h, type, member) \

-       (list_empty(h) ? NULL : list_entry((h)->n.prev, type, member))
+       ((type *)list_tail_((h), container_off((h)->n.next, type, member)))
+
+static inline const void *list_tail_(const struct list_head *h, size_t off)
+{
+       if (list_empty(h))
+               return NULL;
+       return (const char *)h->n.prev - off;
+}

 
 /**
  * list_for_each - iterate through a list.
 
 /**
  * list_for_each - iterate through a list.

- * @h: the list_head
+ * @h: the list_head (warning: evaluated multiple times!)

  * @i: the structure containing the list_node
  * @member: the list_node member of the structure
  *
  * @i: the structure containing the list_node
  * @member: the list_node member of the structure
  *