include/qemu/notify.h

   1 /*
   2  * Notifier lists
   3  *
   4  * Copyright IBM, Corp. 2010
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #ifndef QEMU_NOTIFY_H
  15 #define QEMU_NOTIFY_H
  16
  17 #include "qemu/queue.h"
  18
  19 typedef struct Notifier Notifier;
  20
  21 struct Notifier
  22 {
  23     void (*notify)(Notifier *notifier, void *data);
  24     QLIST_ENTRY(Notifier) node;
  25 };
  26
  27 typedef struct NotifierList
  28 {
  29     QLIST_HEAD(, Notifier) notifiers;
  30 } NotifierList;
  31
  32 #define NOTIFIER_LIST_INITIALIZER(head) \
  33     { QLIST_HEAD_INITIALIZER((head).notifiers) }
  34
  35 void notifier_list_init(NotifierList *list);
  36
  37 void notifier_list_add(NotifierList *list, Notifier *notifier);
  38
  39 void notifier_remove(Notifier *notifier);
  40
  41 void notifier_list_notify(NotifierList *list, void *data);
  42
  43 bool notifier_list_empty(NotifierList *list);
  44
  45 /* Same as Notifier but allows .notify() to return errors */
  46 typedef struct NotifierWithReturn NotifierWithReturn;
  47
  48 struct NotifierWithReturn {
  49     /**
  50      * Return 0 on success (next notifier will be invoked), otherwise
  51      * notifier_with_return_list_notify() will stop and return the value.
  52      */
  53     int (*notify)(NotifierWithReturn *notifier, void *data);
  54     QLIST_ENTRY(NotifierWithReturn) node;
  55 };
  56
  57 typedef struct NotifierWithReturnList {
  58     QLIST_HEAD(, NotifierWithReturn) notifiers;
  59 } NotifierWithReturnList;
  60
  61 #define NOTIFIER_WITH_RETURN_LIST_INITIALIZER(head) \
  62     { QLIST_HEAD_INITIALIZER((head).notifiers) }
  63
  64 void notifier_with_return_list_init(NotifierWithReturnList *list);
  65
  66 void notifier_with_return_list_add(NotifierWithReturnList *list,
  67                                    NotifierWithReturn *notifier);
  68
  69 void notifier_with_return_remove(NotifierWithReturn *notifier);
  70
  71 int notifier_with_return_list_notify(NotifierWithReturnList *list,
  72                                      void *data);
  73
  74 #endif