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willy tarreau80862a32006-04-12 19:15:57 +02001/*
2 * list.h : list manipulation macros and structures.
Willy Tarreaudeb9ed82010-01-03 21:03:22 +01003 * Copyright 2002-2010 Willy Tarreau <w@1wt.eu>
willy tarreau80862a32006-04-12 19:15:57 +02004 *
5 */
6
Willy Tarreau2dd0d472006-06-29 17:53:05 +02007#ifndef _COMMON_MINI_CLIST_H
8#define _COMMON_MINI_CLIST_H
willy tarreau80862a32006-04-12 19:15:57 +02009
Willy Tarreaue3ba5f02006-06-29 18:54:54 +020010#include <common/config.h>
11
willy tarreau80862a32006-04-12 19:15:57 +020012/* these are circular or bidirectionnal lists only. Each list pointer points to
13 * another list pointer in a structure, and not the structure itself. The
14 * pointer to the next element MUST be the first one so that the list is easily
15 * cast as a single linked list or pointer.
16 */
17struct list {
18 struct list *n; /* next */
19 struct list *p; /* prev */
20};
21
Willy Tarreaubc04ce72008-12-07 20:00:15 +010022/* a back-ref is a pointer to a target list entry. It is used to detect when an
23 * element being deleted is currently being tracked by another user. The best
24 * example is a user dumping the session table. The table does not fit in the
25 * output buffer so we have to set a mark on a session and go on later. But if
26 * that marked session gets deleted, we don't want the user's pointer to go in
27 * the wild. So we can simply link this user's request to the list of this
28 * session's users, and put a pointer to the list element in ref, that will be
29 * used as the mark for next iteration.
30 */
31struct bref {
32 struct list users;
33 struct list *ref; /* pointer to the target's list entry */
34};
35
Willy Tarreaudeb9ed82010-01-03 21:03:22 +010036/* a word list is a generic list with a pointer to a string in each element. */
37struct wordlist {
38 struct list list;
39 char *s;
40};
41
Willy Tarreauf4f04122010-01-28 18:10:50 +010042/* this is the same as above with an additional pointer to a condition. */
43struct cond_wordlist {
44 struct list list;
45 void *cond;
46 char *s;
47};
48
Willy Tarreaubd578bb2007-10-28 11:41:06 +010049/* First undefine some macros which happen to also be defined on OpenBSD,
50 * in sys/queue.h, used by sys/event.h
51 */
52#undef LIST_HEAD
53#undef LIST_INIT
54#undef LIST_NEXT
55
Willy Tarreaudc13c112013-06-21 23:16:39 +020056/* ILH = Initialized List Head : used to prevent gcc from moving an empty
57 * list to BSS. Some older version tend to trim all the array and cause
58 * corruption.
59 */
60#define ILH { .n = (struct list *)1, .p = (struct list *)2 }
61
Willy Tarreaubaaee002006-06-26 02:48:02 +020062#define LIST_HEAD(a) ((void *)(&(a)))
63
willy tarreau80862a32006-04-12 19:15:57 +020064#define LIST_INIT(l) ((l)->n = (l)->p = (l))
65
Willy Tarreau2b1dccd2007-05-07 00:18:32 +020066#define LIST_HEAD_INIT(l) { &l, &l }
67
willy tarreau80862a32006-04-12 19:15:57 +020068/* dual linked lists :
69 * Start = (struct list *) pointer to the next elem's prev list entry
70 * For each element :
71 * - prev = pointer to previous element's next (or start). Cannot be NULL
72 * - next = pointer to next element's prev. NULL = end.
73 *
74 */
75
Willy Tarreau40cf67d2007-04-28 12:42:06 +020076/* adds an element at the beginning of a dual-linked list ; returns the element */
Willy Tarreau47d94042008-06-23 22:39:37 +020077#define DLIST_ADD(lh, el) ({ typeof(el) __ret = (el); __ret->n = (void *)(lh); __ret->p = (void *)&(lh); if (likely(__ret->n != NULL)) __ret->n->p = __ret; (lh) = (typeof(lh))&__ret->n; __ret; })
Willy Tarreau40cf67d2007-04-28 12:42:06 +020078
79/* removes an element from a dual-linked list and returns it */
Willy Tarreau47d94042008-06-23 22:39:37 +020080#define DLIST_DEL(el) ({ typeof(el) __ret = (el); if (likely(__ret->n != NULL)) __ret->n->p = __ret->p; __ret->p->n = __ret->n; __ret; })
Willy Tarreau40cf67d2007-04-28 12:42:06 +020081
82/*
83 * iterates through a list of items of type "<struct_type>" which are
84 * linked via a "struct list" member named <struct_member>. The head of the
85 * list is stored at a location designed by <list_head>, which should be a
86 * "struct list *". A variable <end_item> of type "<struct_type>" will
87 * be used as temporary end of list pointer. It can be derived from <list_head>
88 * since this one is only used before. <list_head> will be modified except for
89 * foreach_dlist_item_cst which is slightly slower.
90 * Major difference between FOREACH_ITEM is that it stops at NULL.
91 * Example: foreach_dlist_item(cur_node, args, struct node *, list) { ... };
92 * foreach_dlist_item_cst(cur_node, &node->args, struct node *, list) { ... };
93 */
94#define foreach_dlist_item_cst(iterator, list_head, struct_type, struct_member) \
95 for ((iterator) = LIST_ELEM(&(list_head), struct_type, struct_member.n); \
96 ((iterator)->struct_member.n != NULL) && \
97 (((iterator) = LIST_ELEM((iterator)->struct_member.n, struct_type, struct_member.n)), 1);\
98 )
99
100#define foreach_dlist_item(iterator, var_list_head, struct_type, struct_member) \
101 while ((var_list_head != NULL) && \
102 ((var_list_head=((iterator)=LIST_ELEM(var_list_head, struct_type, struct_member.n))->struct_member.n), 1))
103
104/*
105 * Like foreach_dlist_item, except that this one only operates on the head of
106 * the list. It's to the inner instructions to iterate the list head. If not,
107 * this will be an endless loop.
108 */
109#define while_dlist_item(iterator, var_list_head, struct_type, struct_member) \
110 while ((var_list_head != NULL) && \
111 (((iterator)=LIST_ELEM(var_list_head, struct_type, struct_member.n)),1))
112
113
willy tarreau80862a32006-04-12 19:15:57 +0200114/****** circular lists ********/
115
116/* adds an element at the beginning of a list ; returns the element */
117#define LIST_ADD(lh, el) ({ (el)->n = (lh)->n; (el)->n->p = (lh)->n = (el); (el)->p = (lh); (el); })
118
119/* adds an element at the end of a list ; returns the element */
120#define LIST_ADDQ(lh, el) ({ (el)->p = (lh)->p; (el)->p->n = (lh)->p = (el); (el)->n = (lh); (el); })
121
122/* removes an element from a list and returns it */
123#define LIST_DEL(el) ({ typeof(el) __ret = (el); (el)->n->p = (el)->p; (el)->p->n = (el)->n; (__ret); })
124
125/* returns a pointer of type <pt> to a structure containing a list head called
126 * <el> at address <lh>. Note that <lh> can be the result of a function or macro
127 * since it's used only once.
128 * Example: LIST_ELEM(cur_node->args.next, struct node *, args)
129 */
130#define LIST_ELEM(lh, pt, el) ((pt)(((void *)(lh)) - ((void *)&((pt)NULL)->el)))
131
132/* checks if the list head <lh> is empty or not */
133#define LIST_ISEMPTY(lh) ((lh)->n == (lh))
134
135/* returns a pointer of type <pt> to a structure following the element
136 * which contains list head <lh>, which is known as element <el> in
137 * struct pt.
138 * Example: LIST_NEXT(args, struct node *, list)
139 */
140#define LIST_NEXT(lh, pt, el) (LIST_ELEM((lh)->n, pt, el))
141
142
143/* returns a pointer of type <pt> to a structure preceeding the element
144 * which contains list head <lh>, which is known as element <el> in
145 * struct pt.
146 */
Thierry FOURNIER97ef6f92015-11-03 19:17:37 +0100147#undef LIST_PREV
willy tarreau80862a32006-04-12 19:15:57 +0200148#define LIST_PREV(lh, pt, el) (LIST_ELEM((lh)->p, pt, el))
149
150/*
Willy Tarreaub9c62b92007-05-02 20:46:49 +0200151 * DEPRECATED !!! Use list_for_each_entry() below instead !
152 *
willy tarreau80862a32006-04-12 19:15:57 +0200153 * iterates through a list of items of type "<struct_type>" which are
154 * linked via a "struct list" member named <struct_member>. The head of the
155 * list is stored at a location designed by <list_head>, which should be a
156 * "struct list *". A variable <end_item> of type "<struct_type>" will
157 * be used as temporary end of list pointer. It can be derived from <list_head>
158 * since this one is only used before.
159 * Example: FOREACH_ITEM(cur_node, &node->args, node, struct node *, neigh) { ... };
160 */
161#define FOREACH_ITEM(iterator, list_head, end_item, struct_type, struct_member) \
162 iterator = end_item = LIST_ELEM(list_head, struct_type, struct_member); \
163 while (((iterator) = LIST_ELEM((iterator)->struct_member.n, \
164 struct_type, struct_member)) != (end_item))
165
166/*
Willy Tarreaub9c62b92007-05-02 20:46:49 +0200167 * DEPRECATED !!! Use list_for_each_entry_safe() below instead !
168 *
willy tarreau80862a32006-04-12 19:15:57 +0200169 * idem except that this one is safe against deletion, but it needs a backup
170 * pointer of the element after the iterator.
171 * Example: FOREACH_ITEM_SAFE(cur_node, backup, &node->args, node, struct node *, neigh) { ... };
172 */
173#define FOREACH_ITEM_SAFE(iterator, backup, list_head, end_item, struct_type, struct_member) \
174 end_item = LIST_ELEM(list_head, struct_type, struct_member); \
175 iterator = LIST_ELEM((end_item)->struct_member.n, struct_type, struct_member); \
176 if ((iterator) != (end_item)) \
177 backup = LIST_ELEM((iterator)->struct_member.n, struct_type, struct_member); \
178 for ( ; (iterator) != (end_item); (iterator) = (backup), \
179 backup = LIST_ELEM((iterator)->struct_member.n, struct_type, struct_member))
180
Willy Tarreaub9c62b92007-05-02 20:46:49 +0200181/*
182 * Simpler FOREACH_ITEM macro inspired from Linux sources.
183 * Iterates <item> through a list of items of type "typeof(*item)" which are
184 * linked via a "struct list" member named <member>. A pointer to the head of
185 * the list is passed in <list_head>. No temporary variable is needed. Note
186 * that <item> must not be modified during the loop.
187 * Example: list_for_each_entry(cur_acl, known_acl, list) { ... };
188 */
189#define list_for_each_entry(item, list_head, member) \
190 for (item = LIST_ELEM((list_head)->n, typeof(item), member); \
191 &item->member != (list_head); \
192 item = LIST_ELEM(item->member.n, typeof(item), member))
193
194/*
195 * Simpler FOREACH_ITEM_SAFE macro inspired from Linux sources.
196 * Iterates <item> through a list of items of type "typeof(*item)" which are
197 * linked via a "struct list" member named <member>. A pointer to the head of
198 * the list is passed in <list_head>. A temporary variable <back> of same type
199 * as <item> is needed so that <item> may safely be deleted if needed.
200 * Example: list_for_each_entry_safe(cur_acl, tmp, known_acl, list) { ... };
201 */
202#define list_for_each_entry_safe(item, back, list_head, member) \
203 for (item = LIST_ELEM((list_head)->n, typeof(item), member), \
204 back = LIST_ELEM(item->member.n, typeof(item), member); \
205 &item->member != (list_head); \
206 item = back, back = LIST_ELEM(back->member.n, typeof(back), member))
207
208
Willy Tarreau2dd0d472006-06-29 17:53:05 +0200209#endif /* _COMMON_MINI_CLIST_H */