Add support for generic notifier lists

Notifiers are data-less callbacks and a notifier list is a list of registered
notifiers that all are interested in a particular event.

We'll use this in a few patches to implement mouse change notification.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
---
v1 -> v2
 - Do not do memory allocations by placing list nodes in notifier

1 files changed, 39 insertions, 0 deletions

diff --git a/notify.c b/notify.c
new file mode 100644
index 0000000000..bcd3fc532f
--- /dev/null
+++ b/notify.c
@@ -0,0 +1,39 @@
+/*
+ * 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.
+ *
+ */
+
+#include "qemu-common.h"
+#include "notify.h"
+
+void notifier_list_init(NotifierList *list)
+{
+    QTAILQ_INIT(&list->notifiers);
+}
+
+void notifier_list_add(NotifierList *list, Notifier *notifier)
+{
+    QTAILQ_INSERT_HEAD(&list->notifiers, notifier, node);
+}
+
+void notifier_list_remove(NotifierList *list, Notifier *notifier)
+{
+    QTAILQ_REMOVE(&list->notifiers, notifier, node);
+}
+
+void notifier_list_notify(NotifierList *list)
+{
+    Notifier *notifier, *next;
+
+    QTAILQ_FOREACH_SAFE(notifier, &list->notifiers, node, next) {
+        notifier->notify(notifier);
+    }
+}