On Wed, 28 Jan 2015 11:09:22 +0100
Paolo Bonzini <pbonz...@redhat.com> wrote:
>
>
> On 28/01/2015 11:03, Igor Mammedov wrote:
> > it adds support for weak reference model used by glib's
> > GInitiallyUnowned to QEMU's QOM model.
> >
> > Signed-off-by: Igor Mammedov <imamm...@redhat.com>
> > ---
> > include/qom/object.h | 20 ++++++++++++++++++++
> > qom/object.c | 20 +++++++++++++++++++-
> > 2 files changed, 39 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/qom/object.h b/include/qom/object.h
> > index 89c3092..e0e4cc8 100644
> > --- a/include/qom/object.h
> > +++ b/include/qom/object.h
> > @@ -1314,5 +1314,25 @@ int object_child_foreach(Object *obj, int
> > (*fn)(Object *child, void *opaque),
> > */
> > Object *container_get(Object *root, const char *path);
> >
> > +#define TYPE_UNOWNED_OBJECT "unowned-object"
> > +#define UNOWNED_OBJECT(obj) \
> > + OBJECT_CHECK(UnownedObject, (obj), TYPE_UNOWNED_OBJECT)
> > +#define UNOWNED_OBJECT_CLASS(klass) \
> > + OBJECT_CLASS_CHECK(UnownedObjectClass, (klass), TYPE_UNOWNED_OBJECT)
> > +#define UNOWNED_OBJECT_GET_CLASS \
> > + OBJECT_GET_CLASS(UnownedObjectClass, (obj), TYPE_UNOWNED_OBJECT)
> > +#define OBJECT_WEAK_REF (1UL << 31)
> > +
> > +typedef struct UnownedObjectClass
> > +{
> > + /*< private >*/
> > + ObjectClass parent_class;
> > +} UnownedObjectClass;
> > +
> > +typedef struct UnownedObject
> > +{
> > + /*< private >*/
> > + Object parent_obj;
> > +} UnownedObject;
> >
> > #endif
> > diff --git a/qom/object.c b/qom/object.c
> > index 1812c73..96842c7 100644
> > --- a/qom/object.c
> > +++ b/qom/object.c
> > @@ -705,6 +705,10 @@ void object_ref(Object *obj)
> > if (!obj) {
> > return;
> > }
> > + if (atomic_fetch_and(&obj->ref, ~OBJECT_WEAK_REF) & OBJECT_WEAK_REF)
>
> Please first do a non-atomic test, since this is unlikely to happen but
> atomic_fetch_and is quite expensive (it compiles into a cmpxchg loop).
sure
>
> Paolo
>
> > + {
> > + return;
> > + }
> > atomic_inc(&obj->ref);
> > }
> >
> > @@ -713,7 +717,7 @@ void object_unref(Object *obj)
> > if (!obj) {
> > return;
> > }
> > - g_assert(obj->ref > 0);
> > + g_assert((obj->ref & ~OBJECT_WEAK_REF) > 0);
> >
> > /* parent always holds a reference to its children */
> > if (atomic_fetch_dec(&obj->ref) == 1) {
> > @@ -1709,6 +1713,12 @@ static void object_instance_init(Object *obj)
> > object_property_add_str(obj, "type", qdev_get_type, NULL, NULL);
> > }
> >
> > +
> > +static void unowned_object_instance_init(Object *obj)
> > +{
> > + obj->ref |= OBJECT_WEAK_REF;
> > +}
> > +
> > static void register_types(void)
> > {
> > static TypeInfo interface_info = {
> > @@ -1724,8 +1734,16 @@ static void register_types(void)
> > .abstract = true,
> > };
> >
> > + static TypeInfo unowned_object_info = {
> > + .name = TYPE_UNOWNED_OBJECT,
> > + .instance_size = sizeof(UnownedObject),
> > + .instance_init = unowned_object_instance_init,
> > + .abstract = true,
> > + };
> > +
> > type_interface = type_register_internal(&interface_info);
> > type_register_internal(&object_info);
> > + type_register_internal(&unowned_object_info);
> > }
> >
> > type_init(register_types)
> >
