[Qemu-devel] [PATCH v2 1/2] qom: Implement object_property_add_const_link()

[Eduardo Habkost <ehabkost@redhat.com>]

It can be used in simpler cases where a read-only property is needed.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 include/qom/object.h | 23 +++++++++++++++++++++++
 qom/object.c         | 15 +++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/include/qom/object.h b/include/qom/object.h
index d2d7748..78bb941 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -1123,6 +1123,8 @@ void object_property_add_child(Object *obj, const char *name,
 typedef enum {
     /* Unref the link pointer when the property is deleted */
     OBJ_PROP_LINK_UNREF_ON_RELEASE = 0x1,
+    /* Free the child pointer passed to object_property_add_link() */
+    OBJ_PROP_LINK_FREE_CHILD_POINTER = 0x2,
 } ObjectPropertyLinkFlags;
 
 /**
@@ -1162,6 +1164,8 @@ void object_property_allow_set_link(Object *, const char *,
  * property is deleted with object_property_del().  If the
  * <code>@flags</code> <code>OBJ_PROP_LINK_UNREF_ON_RELEASE</code> bit is set,
  * the reference count is decremented when the property is deleted.
+ * If the <code>OBJ_PROP_LINK_FREE_CHILD_POINTER</code> bit is set,
+ * @child is freed when the property is deleted.
  */
 void object_property_add_link(Object *obj, const char *name,
                               const char *type, Object **child,
@@ -1170,6 +1174,25 @@ void object_property_add_link(Object *obj, const char *name,
                               ObjectPropertyLinkFlags flags,
                               Error **errp);
 
+
+/**
+ * object_property_add_const_link:
+ * @obj: the object to add a property to
+ * @name: the name of the property
+ * @type: the qobj type of the link
+ * @child: pointer to the linked object
+ * @flags: additional options for the link
+ * @errp: if an error occurs, a pointer to an area to store the error
+ *
+ * Like object_property_add_link(), but adds a link property that will
+ * always point to the same object.
+ */
+void object_property_add_const_link(Object *obj, const char *name,
+                                       const char *type, Object *child,
+                                       ObjectPropertyLinkFlags flags,
+                                       Error **errp);
+
+
 /**
  * object_property_add_str:
  * @obj: the object to add a property to
diff --git a/qom/object.c b/qom/object.c
index b8dff43..7d4a46d 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -1227,6 +1227,9 @@ static void object_release_link_property(Object *obj, const char *name,
     if ((prop->flags & OBJ_PROP_LINK_UNREF_ON_RELEASE) && *prop->child) {
         object_unref(*prop->child);
     }
+    if (prop->flags & OBJ_PROP_LINK_FREE_CHILD_POINTER) {
+        g_free(prop->child);
+    }
     g_free(prop);
 }
 
@@ -1266,6 +1269,18 @@ out:
     g_free(full_type);
 }
 
+void object_property_add_const_link(Object *obj, const char *name,
+                                       const char *type, Object *child,
+                                       ObjectPropertyLinkFlags flags,
+                                       Error **errp)
+{
+    Object **childp = g_new0(Object*, 1);
+
+    *childp = child;
+    object_property_add_link(obj, name, type, childp, NULL,
+                             flags | OBJ_PROP_LINK_FREE_CHILD_POINTER, errp);
+}
+
 gchar *object_get_canonical_path_component(Object *obj)
 {
     ObjectProperty *prop = NULL;
-- 
2.1.0