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>
[cherry-picked from d1e70c5e6d1472856c52969301247fe8c3c8389d
    conflicts: used the sys-qeue interface and added required
    LIST_REMOVE_SAFE function to that]

Signed-off-by: Maximilian Heyne <mheyne@amazon.de>
Reviewed-by: Paul Durrant <paul@xen.org>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

diff --git a/Makefile b/Makefile
index 0fbec990b1375b7516b192e232868f1cef0834be..d921bcdf8a891f7b9f70b12f4ab01d4ae391a0da 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -93,6 +93,7 @@ OBJS+=sd.o ssi-sd.o
 OBJS+=bt.o bt-host.o bt-vhci.o bt-l2cap.o bt-sdp.o bt-hci.o bt-hid.o usb-bt.o
 OBJS+=buffered_file.o migration.o migration-tcp.o net.o qemu-sockets.o
 OBJS+=qemu-char.o aio.o net-checksum.o savevm.o cache-utils.o
+OBJS+=notify.o
 
 ifdef CONFIG_BRLAPI
 OBJS+= baum.o

diff --git a/notify.c b/notify.c
new file mode 100644 (file)
index 0000000..59e1e7c
--- /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)
+{
+    LIST_INIT(&list->notifiers);
+}
+
+void notifier_list_add(NotifierList *list, Notifier *notifier)
+{
+    LIST_INSERT_HEAD(&list->notifiers, notifier, node);
+}
+
+void notifier_list_remove(Notifier *notifier)
+{
+    LIST_REMOVE(notifier, node);
+}
+
+void notifier_list_notify(NotifierList *list)
+{
+    Notifier *notifier, *next;
+
+    LIST_FOREACH_SAFE(notifier, &list->notifiers, node, next) {
+        notifier->notify(notifier);
+    }
+}

diff --git a/notify.h b/notify.h
new file mode 100644 (file)
index 0000000..093c63f
--- /dev/null
+++ b/notify.h
@@ -0,0 +1,43 @@
+/*
+ * 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.
+ *
+ */
+
+#ifndef QEMU_NOTIFY_H
+#define QEMU_NOTIFY_H
+
+#include "sys-queue.h"
+
+typedef struct Notifier Notifier;
+
+struct Notifier
+{
+    void (*notify)(Notifier *notifier);
+    LIST_ENTRY(Notifier) node;
+};
+
+typedef struct NotifierList
+{
+    LIST_HEAD(, Notifier) notifiers;
+} NotifierList;
+
+#define NOTIFIER_LIST_INITIALIZER(head) \
+    { LIST_HEAD_INITIALIZER((head).notifiers) }
+
+void notifier_list_init(NotifierList *list);
+
+void notifier_list_add(NotifierList *list, Notifier *notifier);
+
+void notifier_list_remove(Notifier *notifier);
+
+void notifier_list_notify(NotifierList *list);
+
+#endif

diff --git a/sys-queue.h b/sys-queue.h
index 55c26fe7f0cd38a96cc761f230cd620e9a743b5e..81ab044a8cb97aebe3973aff38659ad76ce63590 100644 (file)
--- a/sys-queue.h
+++ b/sys-queue.h
@@ -132,6 +132,11 @@ struct {                                                                \
                 (var);                                                  \
                 (var) = ((var)->field.le_next))
 
+#define LIST_FOREACH_SAFE(var, head, field, next_var)                   \
+        for ((var) = ((head)->lh_first);                                \
+                (var) && ((next_var) = ((var)->field.le_next), 1);      \
+                (var) = (next_var))
+
 /*
  * List access methods.
  */