list: implement list_check_node to check list from node rather than head

diff --git a/ccan/list/list.c b/ccan/list/list.c
index 3d5811011bcc1e034dc1571a622162e8bbfeede6..fad40cb80b3e00938ead3ecbe96c415c55a3973d 100644 (file)
--- a/ccan/list/list.c
+++ b/ccan/list/list.c
@@ -2,32 +2,40 @@
 #include <stdlib.h>
 #include "list.h"
 
-struct list_head *list_check(const struct list_head *h, const char *abortstr)
+struct list_node *list_check_node(const struct list_node *node,
+                                 const char *abortstr)
 {
-       const struct list_node *n, *p;
+       const struct list_node *p, *n;
        int count = 0;
 
-       if (h->n.next == &h->n) {
-               if (h->n.prev != &h->n) {
+       for (p = node, n = node->next; n != node; p = n, n = n->next) {
+               count++;
+               if (n->prev != p) {
                        if (!abortstr)
                                return NULL;
-                       fprintf(stderr, "%s: prev corrupt in empty %p\n",
-                               abortstr, h);
+                       fprintf(stderr,
+                               "%s: prev corrupt in node %p (%u) of %p\n",
+                               abortstr, n, count, node);
                        abort();
                }
-               return (struct list_head *)h;
        }
+       return (struct list_node *)node;
+}
 
-       for (p = &h->n, n = h->n.next; n != &h->n; p = n, n = n->next) {
-               count++;
-               if (n->prev != p) {
+struct list_head *list_check(const struct list_head *h, const char *abortstr)
+{
+       if (h->n.next == &h->n) {
+               if (h->n.prev != &h->n) {
                        if (!abortstr)
                                return NULL;
-                       fprintf(stderr,
-                               "%s: prev corrupt in node %p (%u) of %p\n",
-                               abortstr, n, count, h);
+                       fprintf(stderr, "%s: prev corrupt in empty %p\n",
+                               abortstr, h);
                        abort();
                }
+               return (struct list_head *)h;
        }
+
+       if (!list_check_node(&h->n, abortstr))
+               return NULL;
        return (struct list_head *)h;
 }

diff --git a/ccan/list/list.h b/ccan/list/list.h
index 3496294b52c89acc65ac10f58398ff4e08bfe523..c4956a0d03814145a4d42e3b11a8bce93a611484 100644 (file)
--- a/ccan/list/list.h
+++ b/ccan/list/list.h
@@ -39,7 +39,7 @@ struct list_head
 };
 
 /**
- * list_check - check a list for consistency
+ * list_check - check head of a list for consistency
  * @h: the list_head
  * @abortstr: the location to print on aborting, or NULL.
  *
@@ -51,6 +51,8 @@ struct list_head
  * Returns the list head if the list is consistent, NULL if not (it
  * can never return NULL if @abortstr is set).
  *
+ * See also: list_check_node()
+ *
  * Example:
  *     static void dump_parent(struct parent *p)
  *     {
@@ -64,6 +66,25 @@ struct list_head
  */
 struct list_head *list_check(const struct list_head *h, const char *abortstr);
 
+/**
+ * list_check_node - check node of a list for consistency
+ * @n: the list_node
+ * @abortstr: the location to print on aborting, or NULL.
+ *
+ * Check consistency of the list node is in (it must be in one).
+ *
+ * See also: list_check()
+ *
+ * Example:
+ *     static void dump_child(const struct child *c)
+ *     {
+ *             list_check_node(&c->list, "bad child list");
+ *             printf("%s\n", c->name);
+ *     }
+ */
+struct list_node *list_check_node(const struct list_node *n,
+                                 const char *abortstr);
+
 #ifdef CCAN_LIST_DEBUG
 #define debug_list(h) list_check((h), __func__)
 #else

diff --git a/ccan/list/test/run.c b/ccan/list/test/run.c
index 1a5f093470da87e13912f0ac4ee26bcf83a0e0d2..7c71e396ca36e8823435bf8b81d5e96d4e9b91dc 100644 (file)
--- a/ccan/list/test/run.c
+++ b/ccan/list/test/run.c
@@ -21,7 +21,7 @@ int main(int argc, char *argv[])
        struct child c1, c2, c3, *c, *n;
        unsigned int i;
 
-       plan_tests(44);
+       plan_tests(47);
        /* Test LIST_HEAD, list_empty and check_list */
        ok1(list_empty(&static_list));
        ok1(list_check(&static_list, NULL));
@@ -71,6 +71,11 @@ int main(int argc, char *argv[])
        /* Test list_check */
        ok1(list_check(&parent.children, NULL));
 
+       /* Test list_check_node */
+       ok1(list_check_node(&c1.list, NULL));
+       ok1(list_check_node(&c2.list, NULL));
+       ok1(list_check_node(&c3.list, NULL));
+
        /* Test list_top */
        ok1(list_top(&parent.children, struct child, list) == &c1);