1 /* Licensed under BSD-MIT - see LICENSE file for details */
4 //#define CCAN_LIST_DEBUG 1
7 #include <hkl/ccan/str/str.h>
8 #include <hkl/ccan/container_of/container_of.h>
9 #include <hkl/ccan/check_type/check_type.h>
12 * struct list_node - an entry in a doubly-linked list
13 * @next: next entry (self if empty)
14 * @prev: previous entry (self if empty)
16 * This is used as an entry in a linked list.
20 * // Linked list of all us children.
21 * struct list_node list;
26 struct list_node
*next
, *prev
;
30 * struct list_head - the head of a doubly-linked list
31 * @h: the list_head (containing next and prev pointers)
33 * This is used as the head of a linked list.
37 * struct list_head children;
38 * unsigned int num_children;
47 * list_check - check head of a list for consistency
49 * @abortstr: the location to print on aborting, or NULL.
51 * Because list_nodes have redundant information, consistency checking between
52 * the back and forward links can be done. This is useful as a debugging check.
53 * If @abortstr is non-NULL, that will be printed in a diagnostic if the list
54 * is inconsistent, and the function will abort.
56 * Returns the list head if the list is consistent, NULL if not (it
57 * can never return NULL if @abortstr is set).
59 * See also: list_check_node()
62 * static void dump_parent(struct parent *p)
66 * printf("%s (%u children):\n", p->name, p->num_children);
67 * list_check(&p->children, "bad child list");
68 * list_for_each(&p->children, c, list)
69 * printf(" -> %s\n", c->name);
72 struct list_head
*list_check(const struct list_head
*h
, const char *abortstr
);
75 * list_check_node - check node of a list for consistency
77 * @abortstr: the location to print on aborting, or NULL.
79 * Check consistency of the list node is in (it must be in one).
81 * See also: list_check()
84 * static void dump_child(const struct child *c)
86 * list_check_node(&c->list, "bad child list");
87 * printf("%s\n", c->name);
90 struct list_node
*list_check_node(const struct list_node
*n
,
91 const char *abortstr
);
93 #define LIST_LOC __FILE__ ":" stringify(__LINE__)
94 #ifdef CCAN_LIST_DEBUG
95 #define list_debug(h, loc) list_check((h), loc)
96 #define list_debug_node(n, loc) list_check_node((n), loc)
98 #define list_debug(h, loc) ((void)loc, h)
99 #define list_debug_node(n, loc) ((void)loc, n)
103 * LIST_HEAD_INIT - initializer for an empty list_head
104 * @name: the name of the list.
106 * Explicit initializer for an empty list.
109 * LIST_HEAD, list_head_init()
112 * static struct list_head my_list = LIST_HEAD_INIT(my_list);
114 #define LIST_HEAD_INIT(name) { { &(name).n, &(name).n } }
117 * LIST_HEAD - define and initialize an empty list_head
118 * @name: the name of the list.
120 * The LIST_HEAD macro defines a list_head and initializes it to an empty
121 * list. It can be prepended by "static" to define a static list_head.
124 * LIST_HEAD_INIT, list_head_init()
127 * static LIST_HEAD(my_global_list);
129 #define LIST_HEAD(name) \
130 struct list_head name = LIST_HEAD_INIT(name)
133 * list_head_init - initialize a list_head
134 * @h: the list_head to set to the empty list
138 * struct parent *parent = malloc(sizeof(*parent));
140 * list_head_init(&parent->children);
141 * parent->num_children = 0;
143 static inline void list_head_init(struct list_head
*h
)
145 h
->n
.next
= h
->n
.prev
= &h
->n
;
149 * list_node_init - initialize a list_node
150 * @n: the list_node to link to itself.
152 * You don't need to use this normally! But it lets you list_del(@n)
155 static inline void list_node_init(struct list_node
*n
)
157 n
->next
= n
->prev
= n
;
161 * list_add_after - add an entry after an existing node in a linked list
162 * @h: the list_head to add the node to (for debugging)
163 * @p: the existing list_node to add the node after
164 * @n: the new list_node to add to the list.
166 * The existing list_node must already be a member of the list.
167 * The new list_node does not need to be initialized; it will be overwritten.
170 * struct child c1, c2, c3;
173 * list_add_tail(&h, &c1.list);
174 * list_add_tail(&h, &c3.list);
175 * list_add_after(&h, &c1.list, &c2.list);
177 #define list_add_after(h, p, n) list_add_after_(h, p, n, LIST_LOC)
178 static inline void list_add_after_(struct list_head
*h
,
181 const char *abortstr
)
187 (void)list_debug(h
, abortstr
);
191 * list_add - add an entry at the start of a linked list.
192 * @h: the list_head to add the node to
193 * @n: the list_node to add to the list.
195 * The list_node does not need to be initialized; it will be overwritten.
197 * struct child *child = malloc(sizeof(*child));
199 * child->name = "marvin";
200 * list_add(&parent->children, &child->list);
201 * parent->num_children++;
203 #define list_add(h, n) list_add_(h, n, LIST_LOC)
204 static inline void list_add_(struct list_head
*h
,
206 const char *abortstr
)
208 list_add_after_(h
, &h
->n
, n
, abortstr
);
212 * list_add_before - add an entry before an existing node in a linked list
213 * @h: the list_head to add the node to (for debugging)
214 * @p: the existing list_node to add the node before
215 * @n: the new list_node to add to the list.
217 * The existing list_node must already be a member of the list.
218 * The new list_node does not need to be initialized; it will be overwritten.
221 * list_head_init(&h);
222 * list_add_tail(&h, &c1.list);
223 * list_add_tail(&h, &c3.list);
224 * list_add_before(&h, &c3.list, &c2.list);
226 #define list_add_before(h, p, n) list_add_before_(h, p, n, LIST_LOC)
227 static inline void list_add_before_(struct list_head
*h
,
230 const char *abortstr
)
236 (void)list_debug(h
, abortstr
);
240 * list_add_tail - add an entry at the end of a linked list.
241 * @h: the list_head to add the node to
242 * @n: the list_node to add to the list.
244 * The list_node does not need to be initialized; it will be overwritten.
246 * list_add_tail(&parent->children, &child->list);
247 * parent->num_children++;
249 #define list_add_tail(h, n) list_add_tail_(h, n, LIST_LOC)
250 static inline void list_add_tail_(struct list_head
*h
,
252 const char *abortstr
)
254 list_add_before_(h
, &h
->n
, n
, abortstr
);
258 * list_empty - is a list empty?
261 * If the list is empty, returns true.
264 * assert(list_empty(&parent->children) == (parent->num_children == 0));
266 #define list_empty(h) list_empty_(h, LIST_LOC)
267 static inline bool list_empty_(const struct list_head
*h
, const char* abortstr
)
269 (void)list_debug(h
, abortstr
);
270 return h
->n
.next
== &h
->n
;
274 * list_empty_nodebug - is a list empty (and don't perform debug checks)?
277 * If the list is empty, returns true.
278 * This differs from list_empty() in that if CCAN_LIST_DEBUG is set it
279 * will NOT perform debug checks. Only use this function if you REALLY
280 * know what you're doing.
283 * assert(list_empty_nodebug(&parent->children) == (parent->num_children == 0));
285 #ifndef CCAN_LIST_DEBUG
286 #define list_empty_nodebug(h) list_empty(h)
288 static inline bool list_empty_nodebug(const struct list_head
*h
)
290 return h
->n
.next
== &h
->n
;
295 * list_empty_nocheck - is a list empty?
298 * If the list is empty, returns true. This doesn't perform any
299 * debug check for list consistency, so it can be called without
300 * locks, racing with the list being modified. This is ok for
301 * checks where an incorrect result is not an issue (optimized
302 * bail out path for example).
304 static inline bool list_empty_nocheck(const struct list_head
*h
)
306 return h
->n
.next
== &h
->n
;
310 * list_del - delete an entry from an (unknown) linked list.
311 * @n: the list_node to delete from the list.
313 * Note that this leaves @n in an undefined state; it can be added to
314 * another list, but not deleted again.
317 * list_del_from(), list_del_init()
320 * list_del(&child->list);
321 * parent->num_children--;
323 #define list_del(n) list_del_(n, LIST_LOC)
324 static inline void list_del_(struct list_node
*n
, const char* abortstr
)
326 (void)list_debug_node(n
, abortstr
);
327 n
->next
->prev
= n
->prev
;
328 n
->prev
->next
= n
->next
;
329 #ifdef CCAN_LIST_DEBUG
330 /* Catch use-after-del. */
331 n
->next
= n
->prev
= NULL
;
336 * list_del_init - delete a node, and reset it so it can be deleted again.
337 * @n: the list_node to be deleted.
339 * list_del(@n) or list_del_init() again after this will be safe,
340 * which can be useful in some cases.
343 * list_del_from(), list_del()
346 * list_del_init(&child->list);
347 * parent->num_children--;
349 #define list_del_init(n) list_del_init_(n, LIST_LOC)
350 static inline void list_del_init_(struct list_node
*n
, const char *abortstr
)
352 list_del_(n
, abortstr
);
357 * list_del_from - delete an entry from a known linked list.
358 * @h: the list_head the node is in.
359 * @n: the list_node to delete from the list.
361 * This explicitly indicates which list a node is expected to be in,
362 * which is better documentation and can catch more bugs.
364 * See also: list_del()
367 * list_del_from(&parent->children, &child->list);
368 * parent->num_children--;
370 static inline void list_del_from(struct list_head
*h
, struct list_node
*n
)
372 #ifdef CCAN_LIST_DEBUG
374 /* Thorough check: make sure it was in list! */
376 for (i
= h
->n
.next
; i
!= n
; i
= i
->next
)
379 #endif /* CCAN_LIST_DEBUG */
381 /* Quick test that catches a surprising number of bugs. */
382 assert(!list_empty(h
));
387 * list_swap - swap out an entry from an (unknown) linked list for a new one.
388 * @o: the list_node to replace from the list.
389 * @n: the list_node to insert in place of the old one.
391 * Note that this leaves @o in an undefined state; it can be added to
392 * another list, but not deleted/swapped again.
398 * struct child x1, x2;
401 * list_add(&xh, &x1.list);
402 * list_swap(&x1.list, &x2.list);
404 #define list_swap(o, n) list_swap_(o, n, LIST_LOC)
405 static inline void list_swap_(struct list_node
*o
,
407 const char* abortstr
)
409 (void)list_debug_node(o
, abortstr
);
413 #ifdef CCAN_LIST_DEBUG
414 /* Catch use-after-del. */
415 o
->next
= o
->prev
= NULL
;
420 * list_entry - convert a list_node back into the structure containing it.
422 * @type: the type of the entry
423 * @member: the list_node member of the type
426 * // First list entry is children.next; convert back to child.
427 * child = list_entry(parent->children.n.next, struct child, list);
430 * list_top(), list_for_each()
432 #define list_entry(n, type, member) container_of(n, type, member)
435 * list_top - get the first entry in a list
437 * @type: the type of the entry
438 * @member: the list_node member of the type
440 * If the list is empty, returns NULL.
443 * struct child *first;
444 * first = list_top(&parent->children, struct child, list);
446 * printf("Empty list!\n");
448 #define list_top(h, type, member) \
449 ((type *)list_top_((h), list_off_(type, member)))
451 static inline const void *list_top_(const struct list_head
*h
, size_t off
)
455 return (const char *)h
->n
.next
- off
;
459 * list_pop - remove the first entry in a list
461 * @type: the type of the entry
462 * @member: the list_node member of the type
464 * If the list is empty, returns NULL.
468 * one = list_pop(&parent->children, struct child, list);
470 * printf("Empty list!\n");
472 #define list_pop(h, type, member) \
473 ((type *)list_pop_((h), list_off_(type, member)))
475 static inline const void *list_pop_(const struct list_head
*h
, size_t off
)
483 return (const char *)n
- off
;
487 * list_tail - get the last entry in a list
489 * @type: the type of the entry
490 * @member: the list_node member of the type
492 * If the list is empty, returns NULL.
495 * struct child *last;
496 * last = list_tail(&parent->children, struct child, list);
498 * printf("Empty list!\n");
500 #define list_tail(h, type, member) \
501 ((type *)list_tail_((h), list_off_(type, member)))
503 static inline const void *list_tail_(const struct list_head
*h
, size_t off
)
507 return (const char *)h
->n
.prev
- off
;
511 * list_for_each - iterate through a list.
512 * @h: the list_head (warning: evaluated multiple times!)
513 * @i: the structure containing the list_node
514 * @member: the list_node member of the structure
516 * This is a convenient wrapper to iterate @i over the entire list. It's
517 * a for loop, so you can break and continue as normal.
520 * list_for_each(&parent->children, child, list)
521 * printf("Name: %s\n", child->name);
523 #define list_for_each(h, i, member) \
524 list_for_each_off(h, i, list_off_var_(i, member))
527 * list_for_each_rev - iterate through a list backwards.
529 * @i: the structure containing the list_node
530 * @member: the list_node member of the structure
532 * This is a convenient wrapper to iterate @i over the entire list. It's
533 * a for loop, so you can break and continue as normal.
536 * list_for_each_rev(&parent->children, child, list)
537 * printf("Name: %s\n", child->name);
539 #define list_for_each_rev(h, i, member) \
540 list_for_each_rev_off(h, i, list_off_var_(i, member))
543 * list_for_each_rev_safe - iterate through a list backwards,
544 * maybe during deletion
546 * @i: the structure containing the list_node
547 * @nxt: the structure containing the list_node
548 * @member: the list_node member of the structure
550 * This is a convenient wrapper to iterate @i over the entire list backwards.
551 * It's a for loop, so you can break and continue as normal. The extra
552 * variable * @nxt is used to hold the next element, so you can delete @i
556 * struct child *next;
557 * list_for_each_rev_safe(&parent->children, child, next, list) {
558 * printf("Name: %s\n", child->name);
561 #define list_for_each_rev_safe(h, i, nxt, member) \
562 list_for_each_rev_safe_off(h, i, nxt, list_off_var_(i, member))
565 * list_for_each_safe - iterate through a list, maybe during deletion
567 * @i: the structure containing the list_node
568 * @nxt: the structure containing the list_node
569 * @member: the list_node member of the structure
571 * This is a convenient wrapper to iterate @i over the entire list. It's
572 * a for loop, so you can break and continue as normal. The extra variable
573 * @nxt is used to hold the next element, so you can delete @i from the list.
576 * list_for_each_safe(&parent->children, child, next, list) {
577 * list_del(&child->list);
578 * parent->num_children--;
581 #define list_for_each_safe(h, i, nxt, member) \
582 list_for_each_safe_off(h, i, nxt, list_off_var_(i, member))
585 * list_next - get the next entry in a list
587 * @i: a pointer to an entry in the list.
588 * @member: the list_node member of the structure
590 * If @i was the last entry in the list, returns NULL.
593 * struct child *second;
594 * second = list_next(&parent->children, first, list);
596 * printf("No second child!\n");
598 #define list_next(h, i, member) \
599 ((list_typeof(i))list_entry_or_null(list_debug(h, \
600 __FILE__ ":" stringify(__LINE__)), \
602 list_off_var_((i), member)))
605 * list_prev - get the previous entry in a list
607 * @i: a pointer to an entry in the list.
608 * @member: the list_node member of the structure
610 * If @i was the first entry in the list, returns NULL.
613 * first = list_prev(&parent->children, second, list);
615 * printf("Can't go back to first child?!\n");
617 #define list_prev(h, i, member) \
618 ((list_typeof(i))list_entry_or_null(list_debug(h, \
619 __FILE__ ":" stringify(__LINE__)), \
621 list_off_var_((i), member)))
624 * list_append_list - empty one list onto the end of another.
625 * @to: the list to append into
626 * @from: the list to empty.
628 * This takes the entire contents of @from and moves it to the end of
629 * @to. After this @from will be empty.
632 * struct list_head adopter;
634 * list_append_list(&adopter, &parent->children);
635 * assert(list_empty(&parent->children));
636 * parent->num_children = 0;
638 #define list_append_list(t, f) list_append_list_(t, f, \
639 __FILE__ ":" stringify(__LINE__))
640 static inline void list_append_list_(struct list_head
*to
,
641 struct list_head
*from
,
642 const char *abortstr
)
644 struct list_node
*from_tail
= list_debug(from
, abortstr
)->n
.prev
;
645 struct list_node
*to_tail
= list_debug(to
, abortstr
)->n
.prev
;
647 /* Sew in head and entire list. */
648 to
->n
.prev
= from_tail
;
649 from_tail
->next
= &to
->n
;
650 to_tail
->next
= &from
->n
;
651 from
->n
.prev
= to_tail
;
653 /* Now remove head. */
655 list_head_init(from
);
659 * list_prepend_list - empty one list into the start of another.
660 * @to: the list to prepend into
661 * @from: the list to empty.
663 * This takes the entire contents of @from and moves it to the start
664 * of @to. After this @from will be empty.
667 * list_prepend_list(&adopter, &parent->children);
668 * assert(list_empty(&parent->children));
669 * parent->num_children = 0;
671 #define list_prepend_list(t, f) list_prepend_list_(t, f, LIST_LOC)
672 static inline void list_prepend_list_(struct list_head
*to
,
673 struct list_head
*from
,
674 const char *abortstr
)
676 struct list_node
*from_tail
= list_debug(from
, abortstr
)->n
.prev
;
677 struct list_node
*to_head
= list_debug(to
, abortstr
)->n
.next
;
679 /* Sew in head and entire list. */
680 to
->n
.next
= &from
->n
;
681 from
->n
.prev
= &to
->n
;
682 to_head
->prev
= from_tail
;
683 from_tail
->next
= to_head
;
685 /* Now remove head. */
687 list_head_init(from
);
690 /* internal macros, do not use directly */
691 #define list_for_each_off_dir_(h, i, off, dir) \
692 for (i = list_node_to_off_(list_debug(h, LIST_LOC)->n.dir, \
694 list_node_from_off_((void *)i, (off)) != &(h)->n; \
695 i = list_node_to_off_(list_node_from_off_((void *)i, (off))->dir, \
698 #define list_for_each_safe_off_dir_(h, i, nxt, off, dir) \
699 for (i = list_node_to_off_(list_debug(h, LIST_LOC)->n.dir, \
701 nxt = list_node_to_off_(list_node_from_off_(i, (off))->dir, \
703 list_node_from_off_(i, (off)) != &(h)->n; \
705 nxt = list_node_to_off_(list_node_from_off_(i, (off))->dir, \
709 * list_for_each_off - iterate through a list of memory regions.
711 * @i: the pointer to a memory region wich contains list node data.
712 * @off: offset(relative to @i) at which list node data resides.
714 * This is a low-level wrapper to iterate @i over the entire list, used to
715 * implement all oher, more high-level, for-each constructs. It's a for loop,
716 * so you can break and continue as normal.
718 * WARNING! Being the low-level macro that it is, this wrapper doesn't know
719 * nor care about the type of @i. The only assumption made is that @i points
720 * to a chunk of memory that at some @offset, relative to @i, contains a
721 * properly filled `struct list_node' which in turn contains pointers to
722 * memory chunks and it's turtles all the way down. With all that in mind
723 * remember that given the wrong pointer/offset couple this macro will
724 * happily churn all you memory until SEGFAULT stops it, in other words
727 * It is worth mentioning that one of legitimate use-cases for that wrapper
728 * is operation on opaque types with known offset for `struct list_node'
729 * member(preferably 0), because it allows you not to disclose the type of
733 * list_for_each_off(&parent->children, child,
734 * offsetof(struct child, list))
735 * printf("Name: %s\n", child->name);
737 #define list_for_each_off(h, i, off) \
738 list_for_each_off_dir_((h),(i),(off),next)
741 * list_for_each_rev_off - iterate through a list of memory regions backwards
743 * @i: the pointer to a memory region wich contains list node data.
744 * @off: offset(relative to @i) at which list node data resides.
746 * See list_for_each_off for details
748 #define list_for_each_rev_off(h, i, off) \
749 list_for_each_off_dir_((h),(i),(off),prev)
752 * list_for_each_safe_off - iterate through a list of memory regions, maybe
755 * @i: the pointer to a memory region wich contains list node data.
756 * @nxt: the structure containing the list_node
757 * @off: offset(relative to @i) at which list node data resides.
759 * For details see `list_for_each_off' and `list_for_each_safe'
763 * list_for_each_safe_off(&parent->children, child,
764 * next, offsetof(struct child, list))
765 * printf("Name: %s\n", child->name);
767 #define list_for_each_safe_off(h, i, nxt, off) \
768 list_for_each_safe_off_dir_((h),(i),(nxt),(off),next)
771 * list_for_each_rev_safe_off - iterate backwards through a list of
772 * memory regions, maybe during deletion
774 * @i: the pointer to a memory region wich contains list node data.
775 * @nxt: the structure containing the list_node
776 * @off: offset(relative to @i) at which list node data resides.
778 * For details see `list_for_each_rev_off' and `list_for_each_rev_safe'
782 * list_for_each_rev_safe_off(&parent->children, child,
783 * next, offsetof(struct child, list))
784 * printf("Name: %s\n", child->name);
786 #define list_for_each_rev_safe_off(h, i, nxt, off) \
787 list_for_each_safe_off_dir_((h),(i),(nxt),(off),prev)
789 /* Other -off variants. */
790 #define list_entry_off(n, type, off) \
791 ((type *)list_node_from_off_((n), (off)))
793 #define list_head_off(h, type, off) \
794 ((type *)list_head_off((h), (off)))
796 #define list_tail_off(h, type, off) \
797 ((type *)list_tail_((h), (off)))
799 #define list_add_off(h, n, off) \
800 list_add((h), list_node_from_off_((n), (off)))
802 #define list_del_off(n, off) \
803 list_del(list_node_from_off_((n), (off)))
805 #define list_del_from_off(h, n, off) \
806 list_del_from(h, list_node_from_off_((n), (off)))
808 /* Offset helper functions so we only single-evaluate. */
809 static inline void *list_node_to_off_(struct list_node
*node
, size_t off
)
811 return (void *)((char *)node
- off
);
813 static inline struct list_node
*list_node_from_off_(void *ptr
, size_t off
)
815 return (struct list_node
*)((char *)ptr
+ off
);
818 /* Get the offset of the member, but make sure it's a list_node. */
819 #define list_off_(type, member) \
820 (container_off(type, member) + \
821 check_type(((type *)0)->member, struct list_node))
823 #define list_off_var_(var, member) \
824 (container_off_var(var, member) + \
825 check_type(var->member, struct list_node))
828 #define list_typeof(var) typeof(var)
830 #define list_typeof(var) void *
833 /* Returns member, or NULL if at end of list. */
834 static inline void *list_entry_or_null(const struct list_head
*h
,
835 const struct list_node
*n
,
840 return (char *)n
- off
;
842 #endif /* CCAN_LIST_H */