X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Flist%2Flist.h;h=18f077aec20418c65711230ff051bc85670a2cbb;hp=3496294b52c89acc65ac10f58398ff4e08bfe523;hb=8458811a4126c22635b974718bfbf2876c893c37;hpb=c44953a9b9e6114690968294662fc5120e674cd2 diff --git a/ccan/list/list.h b/ccan/list/list.h index 3496294b..18f077ae 100644 --- a/ccan/list/list.h +++ b/ccan/list/list.h @@ -1,6 +1,8 @@ +/* Licensed under LGPLv2.1+ - see LICENSE file for details */ #ifndef CCAN_LIST_H #define CCAN_LIST_H #include +#include #include /** @@ -39,7 +41,7 @@ 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 +53,8 @@ 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) * { @@ -64,24 +68,62 @@ 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__) +#define list_debug(h) list_check((h), __func__) +#define list_debug_node(n) list_check_node((n), __func__) #else -#define debug_list(h) (h) +#define list_debug(h) (h) +#define list_debug_node(n) (n) #endif /** - * LIST_HEAD - define and initalize an empty list_head + * LIST_HEAD_INIT - initializer for an empty list_head + * @name: the name of the list. + * + * Explicit initializer for an empty list. + * + * See also: + * LIST_HEAD, list_head_init() + * + * Example: + * static struct list_head my_list = LIST_HEAD_INIT(my_list); + */ +#define LIST_HEAD_INIT(name) { { &name.n, &name.n } } + +/** + * LIST_HEAD - define and initialize an empty list_head * @name: the name of the list. * * The LIST_HEAD macro defines a list_head and initializes it to an empty * list. It can be prepended by "static" to define a static list_head. * + * See also: + * LIST_HEAD_INIT, list_head_init() + * * Example: * static LIST_HEAD(my_global_list); */ #define LIST_HEAD(name) \ - struct list_head name = { { &name.n, &name.n } } + struct list_head name = LIST_HEAD_INIT(name) /** * list_head_init - initialize a list_head @@ -118,7 +160,7 @@ static inline void list_add(struct list_head *h, struct list_node *n) n->prev = &h->n; h->n.next->prev = n; h->n.next = n; - (void)debug_list(h); + (void)list_debug(h); } /** @@ -137,22 +179,43 @@ static inline void list_add_tail(struct list_head *h, struct list_node *n) n->prev = h->n.prev; h->n.prev->next = n; h->n.prev = n; - (void)debug_list(h); + (void)list_debug(h); +} + +/** + * 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 a linked list. + * 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--; */ static inline void list_del(struct list_node *n) { + (void)list_debug_node(n); n->next->prev = n->prev; n->prev->next = n->next; - (void)debug_list(n->next); #ifdef CCAN_LIST_DEBUG /* Catch use-after-del. */ n->next = n->prev = NULL; @@ -160,18 +223,33 @@ 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)debug_list(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); } /** @@ -233,7 +311,7 @@ static inline bool list_empty(const struct list_head *h) * printf("Name: %s\n", child->name); */ #define list_for_each(h, i, member) \ - for (i = container_of_var(debug_list(h)->n.next, i, member); \ + for (i = container_of_var(list_debug(h)->n.next, i, member); \ &i->member != &(h)->n; \ i = container_of_var(i->member.next, i, member)) @@ -256,7 +334,7 @@ static inline bool list_empty(const struct list_head *h) * } */ #define list_for_each_safe(h, i, nxt, member) \ - for (i = container_of_var(debug_list(h)->n.next, i, member), \ + for (i = container_of_var(list_debug(h)->n.next, i, member), \ nxt = container_of_var(i->member.next, i, member); \ &i->member != &(h)->n; \ i = nxt, nxt = container_of_var(i->member.next, i, member))