qom: add helpers for UserCreatable object types

The QMP monitor code has two helper methods object_add
and qmp_object_del that are called from several places
in the code (QMP, HMP and main emulator startup).

The HMP and main emulator startup code also share
further logic that extracts the qom-type & id
values from a qdict.

We soon need to use this logic from qemu-img, qemu-io
and qemu-nbd too, but don't want those to depend on
the monitor, nor do we want to duplicate the code.

To avoid this, move some code out of qmp.c and hmp.c
adding new methods to qom/object_interfaces.c

 - user_creatable_add - takes a QDict holding a full
   object definition & instantiates it
 - user_creatable_add_type - takes an ID, type name,
   and QDict holding object properties & instantiates
   it
 - user_creatable_add_opts - takes a QemuOpts holding
   a full object definition & instantiates it
 - user_creatable_add_opts_foreach - variant on
   user_creatable_add_opts which can be directly used
   in conjunction with qemu_opts_foreach.
 - user_creatable_del - takes an ID and deletes the
   corresponding object

The existing code is updated to use these new methods.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1455129674-17255-2-git-send-email-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 174 insertions, 0 deletions

diff --git a/qom/object_interfaces.c b/qom/object_interfaces.c
index f1218f0cc1..c2f6e2998e 100644
--- a/qom/object_interfaces.c
+++ b/qom/object_interfaces.c
@@ -1,6 +1,9 @@
 #include "qemu/osdep.h"
 #include "qom/object_interfaces.h"
 #include "qemu/module.h"
+#include "qapi-visit.h"
+#include "qapi/qmp-output-visitor.h"
+#include "qapi/opts-visitor.h"
 
 void user_creatable_complete(Object *obj, Error **errp)
 {
@@ -31,6 +34,177 @@ bool user_creatable_can_be_deleted(UserCreatable *uc, Error **errp)
     }
 }
 
+
+Object *user_creatable_add(const QDict *qdict,
+                           Visitor *v, Error **errp)
+{
+    char *type = NULL;
+    char *id = NULL;
+    Object *obj = NULL;
+    Error *local_err = NULL, *end_err = NULL;
+    QDict *pdict;
+
+    pdict = qdict_clone_shallow(qdict);
+
+    visit_start_struct(v, NULL, NULL, 0, &local_err);
+    if (local_err) {
+        goto out;
+    }
+
+    qdict_del(pdict, "qom-type");
+    visit_type_str(v, "qom-type", &type, &local_err);
+    if (local_err) {
+        goto out_visit;
+    }
+
+    qdict_del(pdict, "id");
+    visit_type_str(v, "id", &id, &local_err);
+    if (local_err) {
+        goto out_visit;
+    }
+
+    obj = user_creatable_add_type(type, id, pdict, v, &local_err);
+    if (local_err) {
+        goto out_visit;
+    }
+
+ out_visit:
+    visit_end_struct(v, &end_err);
+    if (end_err) {
+        error_propagate(&local_err, end_err);
+        if (obj) {
+            user_creatable_del(id, NULL);
+        }
+        goto out;
+    }
+
+out:
+    QDECREF(pdict);
+    g_free(id);
+    g_free(type);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        object_unref(obj);
+        return NULL;
+    }
+    return obj;
+}
+
+
+Object *user_creatable_add_type(const char *type, const char *id,
+                                const QDict *qdict,
+                                Visitor *v, Error **errp)
+{
+    Object *obj;
+    ObjectClass *klass;
+    const QDictEntry *e;
+    Error *local_err = NULL;
+
+    klass = object_class_by_name(type);
+    if (!klass) {
+        error_setg(errp, "invalid object type: %s", type);
+        return NULL;
+    }
+
+    if (!object_class_dynamic_cast(klass, TYPE_USER_CREATABLE)) {
+        error_setg(errp, "object type '%s' isn't supported by object-add",
+                   type);
+        return NULL;
+    }
+
+    if (object_class_is_abstract(klass)) {
+        error_setg(errp, "object type '%s' is abstract", type);
+        return NULL;
+    }
+
+    obj = object_new(type);
+    if (qdict) {
+        for (e = qdict_first(qdict); e; e = qdict_next(qdict, e)) {
+            object_property_set(obj, v, e->key, &local_err);
+            if (local_err) {
+                goto out;
+            }
+        }
+    }
+
+    object_property_add_child(object_get_objects_root(),
+                              id, obj, &local_err);
+    if (local_err) {
+        goto out;
+    }
+
+    user_creatable_complete(obj, &local_err);
+    if (local_err) {
+        object_property_del(object_get_objects_root(),
+                            id, &error_abort);
+        goto out;
+    }
+out:
+    if (local_err) {
+        error_propagate(errp, local_err);
+        object_unref(obj);
+        return NULL;
+    }
+    return obj;
+}
+
+
+Object *user_creatable_add_opts(QemuOpts *opts, Error **errp)
+{
+    OptsVisitor *ov;
+    QDict *pdict;
+    Object *obj = NULL;
+
+    ov = opts_visitor_new(opts);
+    pdict = qemu_opts_to_qdict(opts, NULL);
+
+    obj = user_creatable_add(pdict, opts_get_visitor(ov), errp);
+    opts_visitor_cleanup(ov);
+    QDECREF(pdict);
+    return obj;
+}
+
+
+int user_creatable_add_opts_foreach(void *opaque, QemuOpts *opts, Error **errp)
+{
+    bool (*type_predicate)(const char *) = opaque;
+    Object *obj = NULL;
+    const char *type;
+
+    type = qemu_opt_get(opts, "qom-type");
+    if (type && type_predicate &&
+        !type_predicate(type)) {
+        return 0;
+    }
+
+    obj = user_creatable_add_opts(opts, errp);
+    if (!obj) {
+        return -1;
+    }
+    object_unref(obj);
+    return 0;
+}
+
+
+void user_creatable_del(const char *id, Error **errp)
+{
+    Object *container;
+    Object *obj;
+
+    container = object_get_objects_root();
+    obj = object_resolve_path_component(container, id);
+    if (!obj) {
+        error_setg(errp, "object '%s' not found", id);
+        return;
+    }
+
+    if (!user_creatable_can_be_deleted(USER_CREATABLE(obj), errp)) {
+        error_setg(errp, "object '%s' is in use, can not be deleted", id);
+        return;
+    }
+    object_unparent(obj);
+}
+
 static void register_types(void)
 {
     static const TypeInfo uc_interface_info = {