On Wed, Oct 21, 2020 at 02:24:08PM +0200, Igor Mammedov wrote:
> On Fri, 9 Oct 2020 12:01:13 -0400
> Eduardo Habkost <ehabk...@redhat.com> wrote:
>
> > The existing object_class_property_add_uint*_ptr() functions are
> > not very useful, because they need a pointer to the property
> > value, which can't really be provided before the object is
> > created.
> >
> > Replace the pointer parameter in those functions with a
> > `ptrdiff_t offset` parameter.
> >
> > Include a uint8 class property in check-qom-proplist unit tests,
> > to ensure the feature is working.
>
>
> Not sure I like approach, it's reinventing qdev pointer properties in QOM
> form.
Yes, and that's on purpose. If we want to eventually merge the
two competing APIs into a single one, we need to make them
converge.
> I had an impression that Paolo wanted qdev pointer properties be gone
> and replaced by something like link properties.
This is completely unrelated to qdev pointer properties and link
properties. The properties that use object_property_add_uint*_ptr()
today are not qdev pointer properties and will never be link
properties. They are just integer properties.
>
> object_property_add_uintXX_ptr() were introduced as a quick hack,
> when ACPI code generation was moved from Seabios, to avoid more
> code shuffling in device models and adding more boiler plate in
> form of custom setters/getters (the later didn't seem to bother
> us everywhere else where we use object_[class_]property_add() ).
> Then it spread little bit to another places.
>
> I'd rather get rid of object_property_add_uintXX_ptr() API altogether
> in favor of object_[class_]property_add() like it is used in other places
> to handle intXX properties.
> Adding helpers similar to object_property_add_bool() for intXX
> could reduce boiler plate need for converting current instances of
> _ptr(), and such helpers would also help with reducing boilerplate
> for the rest of instances where object_[class_]property_add()
> currently is used for dealing with integers.
I find object_property_add_bool() terrible. It requires too much
boilerplate. I actually have plans to introduce
object*_property_add_bool_ptr() to simplify existing
object_property_add_bool() callers.
I don't love object*_property_add_*_ptr() either. I consider the
qdev property API better. But we need a reasonable alternative,
because the qdev API can't be used by non-device objects yet.
I don't think object*_property_add() and
object*_property_add_bool() are reasonable alternatives.
>
>
> > Signed-off-by: Eduardo Habkost <ehabk...@redhat.com>
> > ---
> > Cc: Paolo Bonzini <pbonz...@redhat.com>
> > Cc: "Daniel P. Berrangé" <berra...@redhat.com>
> > Cc: Eduardo Habkost <ehabk...@redhat.com>
> > Cc: qemu-devel@nongnu.org
> > ---
> > include/qom/object.h | 8 ++++----
> > qom/object.c | 36 +++++++++++++++++++++++-------------
> > tests/check-qom-proplist.c | 10 ++++++++--
> > 3 files changed, 35 insertions(+), 19 deletions(-)
> >
> > diff --git a/include/qom/object.h b/include/qom/object.h
> > index d378f13a11..1634294e4f 100644
> > --- a/include/qom/object.h
> > +++ b/include/qom/object.h
> > @@ -1747,7 +1747,7 @@ ObjectProperty *object_property_add_uint8_ptr(Object
> > *obj, const char *name,
> >
> > ObjectProperty *object_class_property_add_uint8_ptr(ObjectClass *klass,
> > const char *name,
> > - const uint8_t *v,
> > + ptrdiff_t offset,
> > ObjectPropertyFlags flags);
> >
> > /**
> > @@ -1768,7 +1768,7 @@ ObjectProperty *object_property_add_uint16_ptr(Object
> > *obj, const char *name,
> >
> > ObjectProperty *object_class_property_add_uint16_ptr(ObjectClass *klass,
> > const char *name,
> > - const uint16_t *v,
> > + ptrdiff_t offset,
> > ObjectPropertyFlags flags);
> >
> > /**
> > @@ -1789,7 +1789,7 @@ ObjectProperty *object_property_add_uint32_ptr(Object
> > *obj, const char *name,
> >
> > ObjectProperty *object_class_property_add_uint32_ptr(ObjectClass *klass,
> > const char *name,
> > - const uint32_t *v,
> > + ptrdiff_t offset,
> > ObjectPropertyFlags flags);
> >
> > /**
> > @@ -1810,7 +1810,7 @@ ObjectProperty *object_property_add_uint64_ptr(Object
> > *obj, const char *name,
> >
> > ObjectProperty *object_class_property_add_uint64_ptr(ObjectClass *klass,
> > const char *name,
> > - const uint64_t *v,
> > + ptrdiff_t offset,
> > ObjectPropertyFlags flags);
> >
> > /**
> > diff --git a/qom/object.c b/qom/object.c
> > index 17692ed5c3..bb32f5d3ad 100644
> > --- a/qom/object.c
> > +++ b/qom/object.c
> > @@ -2450,13 +2450,22 @@ static char *object_get_type(Object *obj, Error
> > **errp)
> > }
> >
> > typedef struct {
> > - /* Pointer to property value */
> > - void *ptr;
> > + bool is_offset;
> > + union {
> > + /* Pointer to property value. Valid if is_offset=false */
> > + void *ptr;
> > + /* Offset in Object struct. Valid if is_offset=true */
> > + ptrdiff_t offset;
> > + };
> > } PointerProperty;
> >
> > static void *pointer_property_get_ptr(Object *obj, PointerProperty *prop)
> > {
> > - return prop->ptr;
> > + if (prop->is_offset) {
> > + return (void *)obj + prop->offset;
> > + } else {
> > + return prop->ptr;
> > + }
> > }
> >
> > static void property_get_uint8_ptr(Object *obj, Visitor *v, const char
> > *name,
> > @@ -2573,10 +2582,11 @@ object_class_property_add_uint_ptr(ObjectClass *oc,
> > const char *name,
> > ObjectPropertyAccessor getter,
> > ObjectPropertyAccessor setter,
> > ObjectPropertyFlags flags,
> > - void *ptr)
> > + ptrdiff_t offset)
> > {
> > PointerProperty *prop = g_new0(PointerProperty, 1);
> > - prop->ptr = ptr;
> > + prop->is_offset = true;
> > + prop->offset = offset;
> > return object_class_property_add(oc, name, type,
> > (flags & OBJ_PROP_FLAG_READ) ? getter
> > : NULL,
> > (flags & OBJ_PROP_FLAG_WRITE) ?
> > setter : NULL,
> > @@ -2597,13 +2607,13 @@ object_property_add_uint8_ptr(Object *obj, const
> > char *name,
> >
> > ObjectProperty *
> > object_class_property_add_uint8_ptr(ObjectClass *klass, const char *name,
> > - const uint8_t *v,
> > + ptrdiff_t offset,
> > ObjectPropertyFlags flags)
> > {
> > return object_class_property_add_uint_ptr(klass, name, "uint8",
> > property_get_uint8_ptr,
> > property_set_uint8_ptr,
> > - flags, (void *)v);
> > + flags, offset);
> > }
> >
> > ObjectProperty *
> > @@ -2620,13 +2630,13 @@ object_property_add_uint16_ptr(Object *obj, const
> > char *name,
> >
> > ObjectProperty *
> > object_class_property_add_uint16_ptr(ObjectClass *klass, const char *name,
> > - const uint16_t *v,
> > + ptrdiff_t offset,
> > ObjectPropertyFlags flags)
> > {
> > return object_class_property_add_uint_ptr(klass, name, "uint16",
> > property_get_uint16_ptr,
> > property_set_uint16_ptr,
> > - flags, (void *)v);
> > + flags, offset);
> > }
> >
> > ObjectProperty *
> > @@ -2643,13 +2653,13 @@ object_property_add_uint32_ptr(Object *obj, const
> > char *name,
> >
> > ObjectProperty *
> > object_class_property_add_uint32_ptr(ObjectClass *klass, const char *name,
> > - const uint32_t *v,
> > + ptrdiff_t offset,
> > ObjectPropertyFlags flags)
> > {
> > return object_class_property_add_uint_ptr(klass, name, "uint32",
> > property_get_uint32_ptr,
> > property_set_uint32_ptr,
> > - flags, (void *)v);
> > + flags, offset);
> > }
> >
> > ObjectProperty *
> > @@ -2666,13 +2676,13 @@ object_property_add_uint64_ptr(Object *obj, const
> > char *name,
> >
> > ObjectProperty *
> > object_class_property_add_uint64_ptr(ObjectClass *klass, const char *name,
> > - const uint64_t *v,
> > + ptrdiff_t offset,
> > ObjectPropertyFlags flags)
> > {
> > return object_class_property_add_uint_ptr(klass, name, "uint64",
> > property_get_uint64_ptr,
> > property_set_uint64_ptr,
> > - flags, (void *)v);
> > + flags, offset);
> > }
> >
> > typedef struct {
> > diff --git a/tests/check-qom-proplist.c b/tests/check-qom-proplist.c
> > index 1b76581980..fba30c20b2 100644
> > --- a/tests/check-qom-proplist.c
> > +++ b/tests/check-qom-proplist.c
> > @@ -61,6 +61,7 @@ struct DummyObject {
> > bool bv;
> > DummyAnimal av;
> > char *sv;
> > + uint8_t u8v;
> > };
> >
> > struct DummyObjectClass {
> > @@ -141,6 +142,9 @@ static void dummy_class_init(ObjectClass *cls, void
> > *data)
> > &dummy_animal_map,
> > dummy_get_av,
> > dummy_set_av);
> > + object_class_property_add_uint8_ptr(cls, "u8v",
> > + offsetof(DummyObject, u8v),
> > + OBJ_PROP_FLAG_READWRITE);
> > }
> >
> >
> > @@ -385,12 +389,14 @@ static void test_dummy_createlist(void)
> > "bv", "yes",
> > "sv", "Hiss hiss hiss",
> > "av", "platypus",
> > + "u8v", "42",
> > NULL));
> >
> > g_assert(err == NULL);
> > g_assert_cmpstr(dobj->sv, ==, "Hiss hiss hiss");
> > g_assert(dobj->bv == true);
> > g_assert(dobj->av == DUMMY_PLATYPUS);
> > + g_assert_cmpint(dobj->u8v, ==, 42);
> >
> > g_assert(object_resolve_path_component(parent, "dummy0")
> > == OBJECT(dobj));
> > @@ -531,7 +537,7 @@ static void test_dummy_iterator(void)
> > {
> > const char *expected[] = {
> > "type", /* inherited from TYPE_OBJECT */
> > - "sv", "av", /* class properties */
> > + "sv", "av", "u8v", /* class properties */
> > "bv"}; /* instance property */
> > Object *parent = object_get_objects_root();
> > DummyObject *dobj = DUMMY_OBJECT(
> > @@ -552,7 +558,7 @@ static void test_dummy_iterator(void)
> >
> > static void test_dummy_class_iterator(void)
> > {
> > - const char *expected[] = { "type", "av", "sv" };
> > + const char *expected[] = { "type", "av", "sv", "u8v" };
> > ObjectPropertyIterator iter;
> > ObjectClass *klass = object_class_by_name(TYPE_DUMMY);
> >
>
--
Eduardo
