4 #include <ccan/container_of/container_of.h>
7 * struct list_node - an entry in a doubly-linked list
8 * @next: next entry (self if empty)
9 * @prev: previous entry (self if empty)
11 * This is used as an entry in a linked list.
15 * // Linked list of all us children.
16 * struct list_node list;
21 struct list_node *next, *prev;
25 * struct list_head - the head of a doubly-linked list
26 * @h: the list_head (containing next and prev pointers)
28 * This is used as the head of a linked list.
32 * struct list_head children;
33 * unsigned int num_children;
42 * list_check - check head of a list for consistency
44 * @abortstr: the location to print on aborting, or NULL.
46 * Because list_nodes have redundant information, consistency checking between
47 * the back and forward links can be done. This is useful as a debugging check.
48 * If @abortstr is non-NULL, that will be printed in a diagnostic if the list
49 * is inconsistent, and the function will abort.
51 * Returns the list head if the list is consistent, NULL if not (it
52 * can never return NULL if @abortstr is set).
54 * See also: list_check_node()
57 * static void dump_parent(struct parent *p)
61 * printf("%s (%u children):\n", p->name, p->num_children);
62 * list_check(&p->children, "bad child list");
63 * list_for_each(&p->children, c, list)
64 * printf(" -> %s\n", c->name);
67 struct list_head *list_check(const struct list_head *h, const char *abortstr);
70 * list_check_node - check node of a list for consistency
72 * @abortstr: the location to print on aborting, or NULL.
74 * Check consistency of the list node is in (it must be in one).
76 * See also: list_check()
79 * static void dump_child(const struct child *c)
81 * list_check_node(&c->list, "bad child list");
82 * printf("%s\n", c->name);
85 struct list_node *list_check_node(const struct list_node *n,
86 const char *abortstr);
88 #ifdef CCAN_LIST_DEBUG
89 #define debug_list(h) list_check((h), __func__)
91 #define debug_list(h) (h)
95 * LIST_HEAD - define and initalize an empty list_head
96 * @name: the name of the list.
98 * The LIST_HEAD macro defines a list_head and initializes it to an empty
99 * list. It can be prepended by "static" to define a static list_head.
102 * static LIST_HEAD(my_global_list);
104 #define LIST_HEAD(name) \
105 struct list_head name = { { &name.n, &name.n } }
108 * list_head_init - initialize a list_head
109 * @h: the list_head to set to the empty list
113 * struct parent *parent = malloc(sizeof(*parent));
115 * list_head_init(&parent->children);
116 * parent->num_children = 0;
118 static inline void list_head_init(struct list_head *h)
120 h->n.next = h->n.prev = &h->n;
124 * list_add - add an entry at the start of a linked list.
125 * @h: the list_head to add the node to
126 * @n: the list_node to add to the list.
128 * The list_node does not need to be initialized; it will be overwritten.
130 * struct child *child = malloc(sizeof(*child));
132 * child->name = "marvin";
133 * list_add(&parent->children, &child->list);
134 * parent->num_children++;
136 static inline void list_add(struct list_head *h, struct list_node *n)
146 * list_add_tail - add an entry at the end of a linked list.
147 * @h: the list_head to add the node to
148 * @n: the list_node to add to the list.
150 * The list_node does not need to be initialized; it will be overwritten.
152 * list_add_tail(&parent->children, &child->list);
153 * parent->num_children++;
155 static inline void list_add_tail(struct list_head *h, struct list_node *n)
165 * list_del - delete an entry from a linked list.
166 * @n: the list_node to delete from the list.
169 * list_del(&child->list);
170 * parent->num_children--;
172 static inline void list_del(struct list_node *n)
174 n->next->prev = n->prev;
175 n->prev->next = n->next;
176 (void)debug_list(n->next);
177 #ifdef CCAN_LIST_DEBUG
178 /* Catch use-after-del. */
179 n->next = n->prev = NULL;
184 * list_empty - is a list empty?
187 * If the list is empty, returns true.
190 * assert(list_empty(&parent->children) == (parent->num_children == 0));
192 static inline bool list_empty(const struct list_head *h)
195 return h->n.next == &h->n;
199 * list_entry - convert a list_node back into the structure containing it.
201 * @type: the type of the entry
202 * @member: the list_node member of the type
205 * // First list entry is children.next; convert back to child.
206 * child = list_entry(parent->children.n.next, struct child, list);
209 * list_top(), list_for_each()
211 #define list_entry(n, type, member) container_of(n, type, member)
214 * list_top - get the first entry in a list
216 * @type: the type of the entry
217 * @member: the list_node member of the type
219 * If the list is empty, returns NULL.
222 * struct child *first;
223 * first = list_top(&parent->children, struct child, list);
225 #define list_top(h, type, member) \
226 (list_empty(h) ? NULL : list_entry((h)->n.next, type, member))
229 * list_tail - get the last entry in a list
231 * @type: the type of the entry
232 * @member: the list_node member of the type
234 * If the list is empty, returns NULL.
237 * struct child *last;
238 * last = list_tail(&parent->children, struct child, list);
240 #define list_tail(h, type, member) \
241 (list_empty(h) ? NULL : list_entry((h)->n.prev, type, member))
244 * list_for_each - iterate through a list.
246 * @i: the structure containing the list_node
247 * @member: the list_node member of the structure
249 * This is a convenient wrapper to iterate @i over the entire list. It's
250 * a for loop, so you can break and continue as normal.
253 * list_for_each(&parent->children, child, list)
254 * printf("Name: %s\n", child->name);
256 #define list_for_each(h, i, member) \
257 for (i = container_of_var(debug_list(h)->n.next, i, member); \
258 &i->member != &(h)->n; \
259 i = container_of_var(i->member.next, i, member))
262 * list_for_each_safe - iterate through a list, maybe during deletion
264 * @i: the structure containing the list_node
265 * @nxt: the structure containing the list_node
266 * @member: the list_node member of the structure
268 * This is a convenient wrapper to iterate @i over the entire list. It's
269 * a for loop, so you can break and continue as normal. The extra variable
270 * @nxt is used to hold the next element, so you can delete @i from the list.
273 * struct child *next;
274 * list_for_each_safe(&parent->children, child, next, list) {
275 * list_del(&child->list);
276 * parent->num_children--;
279 #define list_for_each_safe(h, i, nxt, member) \
280 for (i = container_of_var(debug_list(h)->n.next, i, member), \
281 nxt = container_of_var(i->member.next, i, member); \
282 &i->member != &(h)->n; \
283 i = nxt, nxt = container_of_var(i->member.next, i, member))
284 #endif /* CCAN_LIST_H */