qapi/qom: QAPIfy object-add

This converts object-add from 'gen': false to the ObjectOptions QAPI
type. As an immediate benefit, clients can now use QAPI schema
introspection for user creatable QOM objects.

It is also the first step towards making the QAPI schema the only
external interface for the creation of user creatable objects. Once all
other places (HMP and command lines of the system emulator and all
tools) go through QAPI, too, some object implementations can be
simplified because some checks (e.g. that mandatory options are set) are
already performed by QAPI, and in another step, QOM boilerplate code
could be generated from the schema.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

6 files changed, 32 insertions, 31 deletions

diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c
index a3b69e2709..ac82d54063 100644
--- a/hw/block/xen-block.c
+++ b/hw/block/xen-block.c
@@ -836,17 +836,17 @@ static XenBlockIOThread *xen_block_iothread_create(const char *id,
 {
     ERRP_GUARD();
     XenBlockIOThread *iothread = g_new(XenBlockIOThread, 1);
-    QDict *opts;
-    QObject *ret_data = NULL;
+    ObjectOptions *opts;
 
     iothread->id = g_strdup(id);
 
-    opts = qdict_new();
-    qdict_put_str(opts, "qom-type", TYPE_IOTHREAD);
-    qdict_put_str(opts, "id", id);
-    qmp_object_add(opts, &ret_data, errp);
-    qobject_unref(opts);
-    qobject_unref(ret_data);
+    opts = g_new(ObjectOptions, 1);
+    *opts = (ObjectOptions) {
+        .qom_type = OBJECT_TYPE_IOTHREAD,
+        .id = g_strdup(id),
+    };
+    qmp_object_add(opts, errp);
+    qapi_free_ObjectOptions(opts);
 
     if (*errp) {
         g_free(iothread->id);
diff --git a/include/qom/object_interfaces.h b/include/qom/object_interfaces.h
index 07d5cc8832..9b9938b8c0 100644
--- a/include/qom/object_interfaces.h
+++ b/include/qom/object_interfaces.h
@@ -196,11 +196,4 @@ bool user_creatable_del(const char *id, Error **errp);
  */
 void user_creatable_cleanup(void);
 
-/**
- * qmp_object_add:
- *
- * QMP command handler for object-add. See the QAPI schema for documentation.
- */
-void qmp_object_add(QDict *qdict, QObject **ret_data, Error **errp);
-
 #endif
diff --git a/monitor/misc.c b/monitor/misc.c
index d9ed2bacef..b103bd0a92 100644
--- a/monitor/misc.c
+++ b/monitor/misc.c
@@ -235,8 +235,6 @@ static void monitor_init_qmp_commands(void)
                          qmp_query_qmp_schema, QCO_ALLOW_PRECONFIG);
     qmp_register_command(&qmp_commands, "device_add", qmp_device_add,
                          QCO_NO_OPTIONS);
-    qmp_register_command(&qmp_commands, "object-add", qmp_object_add,
-                         QCO_NO_OPTIONS);
 
     QTAILQ_INIT(&qmp_cap_negotiation_commands);
     qmp_register_command(&qmp_cap_negotiation_commands, "qmp_capabilities",
diff --git a/qapi/qom.json b/qapi/qom.json
index 192a582b07..2056edc072 100644
--- a/qapi/qom.json
+++ b/qapi/qom.json
@@ -846,13 +846,6 @@
 #
 # Create a QOM object.
 #
-# @qom-type: the class name for the object to be created
-#
-# @id: the name of the new object
-#
-# Additional arguments depend on qom-type and are passed to the backend
-# unchanged.
-#
 # Returns: Nothing on success
 #          Error if @qom-type is not a valid class name
 #
@@ -866,9 +859,7 @@
 # <- { "return": {} }
 #
 ##
-{ 'command': 'object-add',
-  'data': {'qom-type': 'str', 'id': 'str'},
-  'gen': false } # so we can get the additional arguments
+{ 'command': 'object-add', 'data': 'ObjectOptions', 'boxed': true }
 
 ##
 # @object-del:
diff --git a/qom/qom-qmp-cmds.c b/qom/qom-qmp-cmds.c
index 19fd5e117f..e577a96adf 100644
--- a/qom/qom-qmp-cmds.c
+++ b/qom/qom-qmp-cmds.c
@@ -19,8 +19,11 @@
 #include "qapi/error.h"
 #include "qapi/qapi-commands-qdev.h"
 #include "qapi/qapi-commands-qom.h"
+#include "qapi/qapi-visit-qom.h"
 #include "qapi/qmp/qdict.h"
 #include "qapi/qmp/qerror.h"
+#include "qapi/qobject-input-visitor.h"
+#include "qapi/qobject-output-visitor.h"
 #include "qemu/cutils.h"
 #include "qom/object_interfaces.h"
 #include "qom/qom-qobject.h"
@@ -223,9 +226,27 @@ ObjectPropertyInfoList *qmp_qom_list_properties(const char *typename,
     return prop_list;
 }
 
-void qmp_object_add(QDict *qdict, QObject **ret_data, Error **errp)
+void qmp_object_add(ObjectOptions *options, Error **errp)
 {
-    user_creatable_add_dict(qdict, false, errp);
+    Visitor *v;
+    QObject *qobj;
+    QDict *props;
+    Object *obj;
+
+    v = qobject_output_visitor_new(&qobj);
+    visit_type_ObjectOptions(v, NULL, &options, &error_abort);
+    visit_complete(v, &qobj);
+    visit_free(v);
+
+    props = qobject_to(QDict, qobj);
+    qdict_del(props, "qom-type");
+    qdict_del(props, "id");
+
+    v = qobject_input_visitor_new(QOBJECT(props));
+    obj = user_creatable_add_type(ObjectType_str(options->qom_type),
+                                  options->id, props, v, errp);
+    object_unref(obj);
+    visit_free(v);
 }
 
 void qmp_object_del(const char *id, Error **errp)
diff --git a/storage-daemon/qemu-storage-daemon.c b/storage-daemon/qemu-storage-daemon.c
index a39a22386a..a118f3abfb 100644
--- a/storage-daemon/qemu-storage-daemon.c
+++ b/storage-daemon/qemu-storage-daemon.c
@@ -148,8 +148,6 @@ static void init_qmp_commands(void)
     qmp_init_marshal(&qmp_commands);
     qmp_register_command(&qmp_commands, "query-qmp-schema",
                          qmp_query_qmp_schema, QCO_ALLOW_PRECONFIG);
-    qmp_register_command(&qmp_commands, "object-add", qmp_object_add,
-                         QCO_NO_OPTIONS);
 
     QTAILQ_INIT(&qmp_cap_negotiation_commands);
     qmp_register_command(&qmp_cap_negotiation_commands, "qmp_capabilities",