[Qemu-devel] [PATCH 04/10] qom: add get_id

[Paolo Bonzini <pbonzini@redhat.com>]

Some classes may present objects differently in errors, for example if they
are not part of the composition tree or if they are not assigned an id by
the user.  Let them do this with a get_id method on Object, and use the
method consistently where a %(device) appears in the error.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/qdev-properties.c  |    6 +++---
 hw/qdev.c             |   15 ++++++++++++++-
 include/qemu/object.h |   11 +++++++++++
 qom/object.c          |   26 +++++++++++++++++++++++++-
 4 files changed, 53 insertions(+), 5 deletions(-)

diff --git a/hw/qdev-properties.c b/hw/qdev-properties.c
index eeb950d..9a6c04a 100644
--- a/hw/qdev-properties.c
+++ b/hw/qdev-properties.c
@@ -931,16 +931,16 @@ void error_set_from_qdev_prop_error(Error **errp, int ret, DeviceState *dev,
     switch (ret) {
     case -EEXIST:
         error_set(errp, QERR_PROPERTY_VALUE_IN_USE,
-                  object_get_typename(OBJECT(dev)), prop->name, value);
+                  object_get_id(OBJECT(dev)), prop->name, value);
         break;
     default:
     case -EINVAL:
         error_set(errp, QERR_PROPERTY_VALUE_BAD,
-                  object_get_typename(OBJECT(dev)), prop->name, value);
+                  object_get_id(OBJECT(dev)), prop->name, value);
         break;
     case -ENOENT:
         error_set(errp, QERR_PROPERTY_VALUE_NOT_FOUND,
-                  object_get_typename(OBJECT(dev)), prop->name, value);
+                  object_get_id(OBJECT(dev)), prop->name, value);
         break;
     case 0:
         break;
diff --git a/hw/qdev.c b/hw/qdev.c
index e909f3b..5d6dc1f 100644
--- a/hw/qdev.c
+++ b/hw/qdev.c
@@ -259,7 +259,7 @@ void qdev_init_nofail(DeviceState *dev)
 {
     if (qdev_init(dev) < 0) {
         error_report("Initialization of device %s failed",
-                     object_get_typename(OBJECT(dev)));
+                     object_get_id(OBJECT(dev)));
         exit(1);
     }
 }
@@ -714,6 +714,13 @@ static void device_finalize(Object *obj)
     }
 }
 
+static const char *qdev_get_id(Object *obj)
+{
+    DeviceState *dev = DEVICE(obj);
+
+    return dev->id?:object_get_typename(obj);
+}
+
 static void device_class_base_init(ObjectClass *class, void *data)
 {
     DeviceClass *klass = DEVICE_CLASS(class);
@@ -744,6 +751,11 @@ Object *qdev_get_machine(void)
     return dev;
 }
 
+static void device_class_init(ObjectClass *class, void *data)
+{
+    class->get_id = qdev_get_id;
+}
+
 static TypeInfo device_type_info = {
     .name = TYPE_DEVICE,
     .parent = TYPE_OBJECT,
@@ -751,6 +763,7 @@ static TypeInfo device_type_info = {
     .instance_init = device_initfn,
     .instance_finalize = device_finalize,
     .class_base_init = device_class_base_init,
+    .class_init = device_class_init,
     .abstract = true,
     .class_size = sizeof(DeviceClass),
 };
diff --git a/include/qemu/object.h b/include/qemu/object.h
index e714c2c..cb08cfa 100644
--- a/include/qemu/object.h
+++ b/include/qemu/object.h
@@ -239,6 +239,9 @@ struct ObjectClass
 {
     /*< private >*/
     Type type;
+
+    /*< public >*/
+    const char *(*get_id)(Object *);
 };
 
 /**
@@ -501,6 +504,14 @@ Object *object_dynamic_cast(Object *obj, const char *typename);
 Object *object_dynamic_cast_assert(Object *obj, const char *typename);
 
 /**
+ * object_get_id:
+ * @obj: A derivative of #Object
+ *
+ * Returns: A string that can be used to refer to @obj.
+ */
+const char *object_get_id(Object *obj);
+
+/**
  * object_get_class:
  * @obj: A derivative of #Object
  *
diff --git a/qom/object.c b/qom/object.c
index 68a4c57..b19ef94 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -334,6 +334,24 @@ static void object_property_del_child(Object *obj, Object *child, Error **errp)
     }
 }
 
+static const char *_object_get_id(Object *obj)
+{
+    ObjectProperty *prop;
+
+    QTAILQ_FOREACH(prop, &obj->properties, node) {
+        if (strstart(prop->type, "child<", NULL) && prop->opaque == obj) {
+            return prop->name;
+        }
+    }
+
+    return "";
+}
+
+const char *object_get_id(Object *obj)
+{
+    return obj->class->get_id(obj);
+}
+
 void object_unparent(Object *obj)
 {
     if (obj->parent) {
@@ -672,7 +690,7 @@ ObjectProperty *object_property_find(Object *obj, const char *name, Error **errp
         }
     }
 
-    error_set(errp, QERR_PROPERTY_NOT_FOUND, "", name);
+    error_set(errp, QERR_PROPERTY_NOT_FOUND, object_get_id(obj), name);
     return NULL;
 }
 
@@ -1236,6 +1254,11 @@ static void object_instance_init(Object *obj)
     object_property_add_str(obj, "type", qdev_get_type, NULL, NULL);
 }
 
+static void object_class_init(ObjectClass *klass, void *class_data)
+{
+    klass->get_id = _object_get_id;
+}
+
 static void register_types(void)
 {
     static TypeInfo interface_info = {
@@ -1248,6 +1271,7 @@ static void register_types(void)
         .name = TYPE_OBJECT,
         .instance_size = sizeof(Object),
         .instance_init = object_instance_init,
+        .class_init = object_class_init,
         .abstract = true,
     };
 
-- 
1.7.10.1