From dc0aafc9d58e231f5d6d70c9838b151a162428b1 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Sat, 1 Jan 2011 17:11:15 +1030 Subject: [PATCH] list: list_del_from() Deletion from a specific list. --- ccan/list/list.h | 53 ++++++++++++++++++++++++++++----- ccan/list/test/run-with-debug.c | 8 +++-- ccan/list/test/run.c | 8 +++-- 3 files changed, 55 insertions(+), 14 deletions(-) diff --git a/ccan/list/list.h b/ccan/list/list.h index 5b4f81c9..02835a6b 100644 --- a/ccan/list/list.h +++ b/ccan/list/list.h @@ -1,6 +1,7 @@ #ifndef CCAN_LIST_H #define CCAN_LIST_H #include +#include #include /** @@ -164,9 +165,30 @@ static inline void list_add_tail(struct list_head *h, struct list_node *n) } /** - * list_del - delete an entry from a linked list. + * list_empty - is a list empty? + * @h: the list_head + * + * If the list is empty, returns true. + * + * Example: + * assert(list_empty(&parent->children) == (parent->num_children == 0)); + */ +static inline bool list_empty(const struct list_head *h) +{ + (void)list_debug(h); + return h->n.next == &h->n; +} + +/** + * list_del - delete an entry from an (unknown) linked list. * @n: the list_node to delete from the list. * + * Note that this leaves @n in an undefined state; it can be added to + * another list, but not deleted again. + * + * See also: + * list_del_from() + * * Example: * list_del(&child->list); * parent->num_children--; @@ -183,18 +205,33 @@ static inline void list_del(struct list_node *n) } /** - * list_empty - is a list empty? - * @h: the list_head + * list_del_from - delete an entry from a known linked list. + * @h: the list_head the node is in. + * @n: the list_node to delete from the list. * - * If the list is empty, returns true. + * This explicitly indicates which list a node is expected to be in, + * which is better documentation and can catch more bugs. + * + * See also: list_del() * * Example: - * assert(list_empty(&parent->children) == (parent->num_children == 0)); + * list_del_from(&parent->children, &child->list); + * parent->num_children--; */ -static inline bool list_empty(const struct list_head *h) +static inline void list_del_from(struct list_head *h, struct list_node *n) { - (void)list_debug(h); - return h->n.next == &h->n; +#ifdef CCAN_LIST_DEBUG + { + /* Thorough check: make sure it was in list! */ + struct list_node *i; + for (i = h->n.next; i != n; i = i->next) + assert(i != &h->n); + } +#endif /* CCAN_LIST_DEBUG */ + + /* Quick test that catches a surprising number of bugs. */ + assert(!list_empty(h)); + list_del(n); } /** diff --git a/ccan/list/test/run-with-debug.c b/ccan/list/test/run-with-debug.c index d34c660e..f76bccc1 100644 --- a/ccan/list/test/run-with-debug.c +++ b/ccan/list/test/run-with-debug.c @@ -102,21 +102,23 @@ int main(int argc, char *argv[]) } ok1(i == 3); - /* Test list_for_each_safe and list_del. */ + /* Test list_for_each_safe, list_del and list_del_from. */ i = 0; list_for_each_safe(&parent.children, c, n, list) { switch (i++) { case 0: - ok1(c == &c1); + ok1(c == &c1); + list_del(&c->list); break; case 1: ok1(c == &c2); + list_del_from(&parent.children, &c->list); break; case 2: ok1(c == &c3); + list_del_from(&parent.children, &c->list); break; } - list_del(&c->list); ok1(list_check(&parent.children, NULL)); if (i > 2) break; diff --git a/ccan/list/test/run.c b/ccan/list/test/run.c index 7c71e396..13a1da41 100644 --- a/ccan/list/test/run.c +++ b/ccan/list/test/run.c @@ -101,21 +101,23 @@ int main(int argc, char *argv[]) } ok1(i == 3); - /* Test list_for_each_safe and list_del. */ + /* Test list_for_each_safe, list_del and list_del_from. */ i = 0; list_for_each_safe(&parent.children, c, n, list) { switch (i++) { case 0: - ok1(c == &c1); + ok1(c == &c1); + list_del(&c->list); break; case 1: ok1(c == &c2); + list_del_from(&parent.children, &c->list); break; case 2: ok1(c == &c3); + list_del_from(&parent.children, &c->list); break; } - list_del(&c->list); ok1(list_check(&parent.children, NULL)); if (i > 2) break; -- 2.39.2