qemu/util/notify.c
Stefan Hajnoczi 5dae8e5fb8 notify: add NotiferWithReturn so notifier list can abort
notifier_list_notify() has no return value.  This is fine when we just
want to invoke side-effects.

Sometimes it's useful for notifiers to produce a return value.  This
allows notifiers to "veto" an operation and will be used by the block
layer before-write notifier.

Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-28 09:20:26 +02:00

72 lines
1.6 KiB
C

/*
* Notifier lists
*
* Copyright IBM, Corp. 2010
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#include "qemu-common.h"
#include "qemu/notify.h"
void notifier_list_init(NotifierList *list)
{
QLIST_INIT(&list->notifiers);
}
void notifier_list_add(NotifierList *list, Notifier *notifier)
{
QLIST_INSERT_HEAD(&list->notifiers, notifier, node);
}
void notifier_remove(Notifier *notifier)
{
QLIST_REMOVE(notifier, node);
}
void notifier_list_notify(NotifierList *list, void *data)
{
Notifier *notifier, *next;
QLIST_FOREACH_SAFE(notifier, &list->notifiers, node, next) {
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;
}