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/*
* safe_list - linked list protected against recursive iteration with deletes
*
* Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "safe_list.h"
struct safe_list_iterator {
struct safe_list_iterator **head;
struct safe_list_iterator *next_i;
struct safe_list *next;
};
static void
__safe_list_set_iterator(struct safe_list *list,
struct safe_list_iterator *i)
{
struct safe_list_iterator *next_i;
struct safe_list *next;
next = list_entry(list->list.next, struct safe_list, list);
next_i = next->i;
next->i = i;
i->next = next;
i->head = &next->i;
i->next_i = next_i;
if (next_i)
next_i->head = &i->next_i;
}
static void
__safe_list_del_iterator(struct safe_list_iterator *i)
{
*i->head = i->next_i;
if (i->next_i)
i->next_i->head = i->head;
}
static void
__safe_list_move_iterator(struct safe_list *list,
struct safe_list_iterator *i)
{
__safe_list_del_iterator(i);
__safe_list_set_iterator(list, i);
}
int safe_list_for_each(struct safe_list *head,
int (*cb)(void *ctx, struct safe_list *list),
void *ctx)
{
struct safe_list_iterator i;
struct safe_list *cur;
int ret = 0;
for (cur = list_entry(head->list.next, struct safe_list, list),
__safe_list_set_iterator(cur, &i);
cur != head;
cur = i.next, __safe_list_move_iterator(cur, &i)) {
ret = cb(ctx, cur);
if (ret)
break;
}
__safe_list_del_iterator(&i);
return ret;
}
void safe_list_add(struct safe_list *list, struct safe_list *head)
{
list->i = NULL;
list_add_tail(&list->list, &head->list);
}
void safe_list_add_first(struct safe_list *list, struct safe_list *head)
{
list->i = NULL;
list_add(&list->list, &head->list);
}
void safe_list_del(struct safe_list *list)
{
struct safe_list_iterator *i, *next_i, **tail;
struct safe_list *next;
next = list_entry(list->list.next, struct safe_list, list);
list_del(&list->list);
if (!list->i)
return;
next_i = next->i;
tail = &next->i;
for (i = list->i; i; i = i->next_i) {
tail = &i->next_i;
i->next = next;
}
next->i = list->i;
list->i->head = &next->i;
*tail = next_i;
if (next_i)
next_i->head = tail;
list->i = NULL;
}
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