On 07/07/2026 13:17, Daniel P. Berrangé wrote:
On Fri, Jul 03, 2026 at 02:53:04PM +0100, Mark Cave-Ayland wrote:
This adds a class property that references a uint8_t within the object instance
and is intended to be a replacement for object_property_add_uint8_ptr().
Signed-off-by: Mark Cave-Ayland <[email protected]>
---
include/qom/object.h | 5 +++++
qom/object.c | 52 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 57 insertions(+)
diff --git a/include/qom/object.h b/include/qom/object.h
index 89c23d45ab..a55f9d0e97 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -1956,6 +1956,11 @@ ObjectProperty *object_property_add_uint8_ptr(Object
*obj, const char *name,
const uint8_t *v,
ObjectPropertyFlags flags);
+ObjectProperty *object_class_property_add_uint8_ptr(ObjectClass *klass,
+ const char *name,
+ ptrdiff_t v,
+ ObjectPropertyFlags flags);
+
ObjectProperty *object_class_static_property_add_uint8_ptr(ObjectClass *klass,
const char *name,
const uint8_t *v,
diff --git a/qom/object.c b/qom/object.c
index d10bf848c0..263c313cd2 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -2741,6 +2741,38 @@ static void property_set_uint64_ptr(Object *obj, Visitor
*v, const char *name,
*field = value;
}
+static void *object_class_prop_ptr(Object *obj, ptrdiff_t offset)
+{
+ void *ptr = obj;
+ ptr += offset;
+
+ return ptr;
+}
Perhaps just
#define FIELD(obj, offset) ((void *)obj+(ptrdiff_t)offset)
That could work.
+
+static void property_class_get_uint8_ptr(Object *obj, Visitor *v,
+ const char *name,
+ void *opaque, Error **errp)
+{
+ uint8_t value = *(uint8_t *)object_class_prop_ptr(obj,
+ (ptrdiff_t)opaque);
Do we need this intermediate instead of now
+ visit_type_uint8(v, name, &value, errp);
visit_type_uint8(v, name, FIELD(obj, opaque), errp);
Yes, I think that would be possible. I shall give it a test and report back.
+}
+
+static void property_class_set_uint8_ptr(Object *obj, Visitor *v,
+ const char *name,
+ void *opaque, Error **errp)
+{
+ uint8_t *field = (uint8_t *)object_class_prop_ptr(obj,
+ (ptrdiff_t)opaque);
+ uint8_t value;
+
+ if (!visit_type_uint8(v, name, &value, errp)) {
+ return;
+ }
+
+ *field = value;
Instead of all this is it sufficient to do:
visit_type_uint8(v, name, FIELD(obj, opaque), errp);
Also, since we'll be using this pattern for int8, int16, int32,
and many more, perhaps we could define a macro that can expand
to the getter/setter impl for any scalar type. so we can do
DEFINE_SCALAR_PROP_CALLBACKS(uint8);
DEFINE_SCALAR_PROP_CALLBACKS(uint16);
DEFINE_SCALAR_PROP_CALLBACKS(uint32);
DEFINE_SCALAR_PROP_CALLBACKS(uint64);
DEFINE_SCALAR_PROP_CALLBACKS(bool);
..etc..
That is something else that is possible: I've purposely avoided doing
this since it's not a pattern already in use within object.c. Do you
think this is worth doing as a separate exercise first?
+}
+
ObjectProperty *
object_property_add_uint8_ptr(Object *obj, const char *name,
const uint8_t *v,
ATB,
Mark.
