diff --git a/include/qemu/notify.h b/include/qemu/notify.h index 4e2e7f0ec4db0aa63c4e5450b7d64467b4cb76aa..a3d73e4bc7604905dd32aa5b0dc49e6aa207ea6b 100644 --- a/include/qemu/notify.h +++ b/include/qemu/notify.h @@ -40,4 +40,33 @@ void notifier_remove(Notifier *notifier); void notifier_list_notify(NotifierList *list, void *data); +/* Same as Notifier but allows .notify() to return errors */ +typedef struct NotifierWithReturn NotifierWithReturn; + +struct NotifierWithReturn { + /** + * Return 0 on success (next notifier will be invoked), otherwise + * notifier_with_return_list_notify() will stop and return the value. + */ + int (*notify)(NotifierWithReturn *notifier, void *data); + QLIST_ENTRY(NotifierWithReturn) node; +}; + +typedef struct NotifierWithReturnList { + QLIST_HEAD(, NotifierWithReturn) notifiers; +} NotifierWithReturnList; + +#define NOTIFIER_WITH_RETURN_LIST_INITIALIZER(head) \ + { QLIST_HEAD_INITIALIZER((head).notifiers) } + +void notifier_with_return_list_init(NotifierWithReturnList *list); + +void notifier_with_return_list_add(NotifierWithReturnList *list, + NotifierWithReturn *notifier); + +void notifier_with_return_remove(NotifierWithReturn *notifier); + +int notifier_with_return_list_notify(NotifierWithReturnList *list, + void *data); + #endif diff --git a/util/notify.c b/util/notify.c index 7b7692acb2c84492d39ccecf2f2fb8cc2e6d5c46..f215dfc2142d230ce155e9c1970ee199efb1c779 100644 --- a/util/notify.c +++ b/util/notify.c @@ -39,3 +39,33 @@ void notifier_list_notify(NotifierList *list, void *data) notifier->notify(notifier, data); } } + +void notifier_with_return_list_init(NotifierWithReturnList *list) +{ + QLIST_INIT(&list->notifiers); +} + +void notifier_with_return_list_add(NotifierWithReturnList *list, + NotifierWithReturn *notifier) +{ + QLIST_INSERT_HEAD(&list->notifiers, notifier, node); +} + +void notifier_with_return_remove(NotifierWithReturn *notifier) +{ + QLIST_REMOVE(notifier, node); +} + +int notifier_with_return_list_notify(NotifierWithReturnList *list, void *data) +{ + NotifierWithReturn *notifier, *next; + int ret = 0; + + QLIST_FOREACH_SAFE(notifier, &list->notifiers, node, next) { + ret = notifier->notify(notifier, data); + if (ret != 0) { + break; + } + } + return ret; +}