Re: [Qemu-devel] [PATCH 03/25] qom: add class_base_init

[Anthony Liguori]

On 04/03/2012 06:15 AM, Paolo Bonzini wrote:

The class_base_init TypeInfo callback was present in one of the early
QOM versions but removed (on my request...) before committing.  We
will need it soon, add it.

Signed-off-by: Paolo Bonzini<pbonz...@redhat.com>

Heh, funny how that worked out :-)

Reviewed-by: Anthony Liguori <aligu...@us.ibm.com>

Regards,

Anthony Liguori

---
  include/qemu/object.h |   10 ++++++++--
  qom/object.c          |    9 +++++++++
  2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/include/qemu/object.h b/include/qemu/object.h
index 470efe3..ccaea7d 100644
--- a/include/qemu/object.h
+++ b/include/qemu/object.h
@@ -291,10 +291,15 @@ struct Object
   *   has occurred to allow a class to set its default virtual method pointers.
   *   This is also the function to use to override virtual methods from a 
parent
   *   class.
+ * @class_base_init: This function is called for all base classes after all
+ *   parent class initialization has occurred, but before the class itself
+ *   is initialized.  This is the function to use to undo the effects of
+ *   memcpy from the parent class to the descendents.
   * @class_finalize: This function is called during class destruction and is
   *   meant to release and dynamic parameters allocated by @class_init.
- * @class_data: Data to pass to the @class_init and @class_finalize functions.
- *   This can be useful when building dynamic classes.
+ * @class_data: Data to pass to the @class_init, @class_base_init and
+ *   @class_finalize functions.  This can be useful when building dynamic
+ *   classes.
   * @interfaces: The list of interfaces associated with this type.  This
   *   should point to a static array that's terminated with a zero filled
   *   element.
@@ -312,6 +317,7 @@ struct TypeInfo
      size_t class_size;

      void (*class_init)(ObjectClass *klass, void *data);
+    void (*class_base_init)(ObjectClass *klass, void *data);
      void (*class_finalize)(ObjectClass *klass, void *data);
      void *class_data;

diff --git a/qom/object.c b/qom/object.c
index 4975d93..6ff1c19 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -45,6 +45,7 @@ struct TypeImpl
      size_t instance_size;

      void (*class_init)(ObjectClass *klass, void *data);
+    void (*class_base_init)(ObjectClass *klass, void *data);
      void (*class_finalize)(ObjectClass *klass, void *data);

      void *class_data;
@@ -112,6 +113,7 @@ TypeImpl *type_register(const TypeInfo *info)
      ti->instance_size = info->instance_size;

      ti->class_init = info->class_init;
+    ti->class_base_init = info->class_base_init;
      ti->class_finalize = info->class_finalize;
      ti->class_data = info->class_data;

@@ -232,6 +234,13 @@ static void type_initialize(TypeImpl *ti)
          memcpy((void *)ti->class + sizeof(ObjectClass),
                 (void *)parent->class + sizeof(ObjectClass),
                 parent->class_size - sizeof(ObjectClass));
+
+        while (parent) {
+            if (parent->class_base_init) {
+                parent->class_base_init(ti->class, ti->class_data);
+            }
+            parent = type_get_parent(parent);
+        }
      }

      memset((void *)ti->class + class_size, 0, ti->class_size - class_size);