safe_list: add a new linked list variant

[project/libubox.git] / safe_list.h

diff --git a/safe_list.h b/safe_list.h
new file mode 100644 (file)
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--- /dev/null
+++ b/safe_list.h
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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.
+ */
+
+/*
+ * Use this linked list implementation as a replacement for list.h if you
+ * want to allow deleting arbitrary list entries from within one or more
+ * recursive iterator calling context
+ */
+
+#ifndef __LIBUBOX_SAFE_LIST_H
+#define __LIBUBOX_SAFE_LIST_H
+
+#include <stdbool.h>
+#include "list.h"
+#include "utils.h"
+
+struct safe_list;
+struct safe_list_terator;
+
+struct safe_list {
+       struct list_head list;
+       struct safe_list_iterator *i;
+};
+
+int safe_list_for_each(struct safe_list *list,
+                      int (*cb)(void *ctx, struct safe_list *list),
+                      void *ctx);
+
+void safe_list_add(struct safe_list *list, struct safe_list *head);
+void safe_list_del(struct safe_list *list);
+
+#define INIT_SAFE_LIST(_head) \
+       do { \
+               INIT_LIST_HEAD(_head.list); \
+               (_head)->i = NULL; \
+       } while (0)
+
+#define SAFE_LIST_INIT(_name) { LIST_HEAD_INIT(_name.list), NULL }
+#define SAFE_LIST(_name)       struct safe_list _name = SAFE_LIST_INIT(_name)
+
+#endif