src/notifier.h

   1 /*
   2  * transsip - the telephony toolkit
   3  * By Daniel Borkmann <daniel@transsip.org>
   4  * Copyright 2011, 2012 Daniel Borkmann <dborkma@tik.ee.ethz.ch>
   5  * Subject to the GPL, version 2.
   6  */
   7
   8 #ifndef NOTIFIER_H
   9 #define NOTIFIER_H
  10
  11 #include <stdint.h>
  12 #include <stdio.h>
  13
  14 #include "locking.h"
  15
  16 #define BLOCK_SUCC_DONE   0
  17 #define BLOCK_STOP_CHAIN  1
  18
  19 enum event_prio {
  20         PRIO_VERYLOW,
  21         PRIO_LOW,
  22         PRIO_MEDIUM,
  23         PRIO_HIGH,
  24         PRIO_EXTRA,
  25 };
  26
  27 struct event_block {
  28         enum event_prio prio;
  29         int (*hook)(const struct event_block *self, unsigned long event,
  30                     const void *arg);
  31         struct event_block *next;
  32 };
  33
  34 struct event_head {
  35         struct event_block *head;
  36         struct mutexlock lock;
  37 };
  38
  39 static inline void init_event_head(struct event_head *head)
  40 {
  41         head->head = NULL;
  42         mutexlock_init(&head->lock);
  43 }
  44
  45 extern int register_event_hook(struct event_block **head,
  46                                struct event_block *block);
  47 extern int register_event_hook_once(struct event_block **head,
  48                                     struct event_block *block);
  49 extern int unregister_event_hook(struct event_block **head,
  50                                  struct event_block *block);
  51 extern int call_event_hooks(struct event_block **head, unsigned long event,
  52                             const void *arg, int *called);
  53
  54 #endif /* NOTIFIER_H */