rust: qom: put class_init together from multiple ClassInitImpl<>

Parameterize the implementation of ClassInitImpl so that it is
possible to call up the chain of implementations, one superclass at
a time starting at ClassInitImpl<Self::Class>.

In order to avoid having to implement (for example)
ClassInitImpl<PL011Class>, also remove the dummy PL011Class and
PL011LuminaryClass structs and specify the same ObjectType::Class as
the superclass.  In the future this default behavior can be handled by
a procedural macro, by looking at the first field in the struct.

Note that the new trait is safe: the calls are started by
rust_class_init<>(), which is not public and can convert the class
pointer to a Rust reference.

Since CLASS_BASE_INIT applies to the type that is being defined,
and only to it, move it to ObjectImpl.

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 1 insertions, 8 deletions

diff --git a/rust/qemu-api/tests/tests.rs b/rust/qemu-api/tests/tests.rs
index 278efe967f..ed3a555e76 100644
--- a/rust/qemu-api/tests/tests.rs
+++ b/rust/qemu-api/tests/tests.rs
@@ -26,11 +26,6 @@ fn test_device_decl_macros() {
         pub migrate_clock: bool,
     }
 
-    #[repr(C)]
-    pub struct DummyClass {
-        pub _parent: DeviceClass,
-    }
-
     declare_properties! {
         DUMMY_PROPERTIES,
             define_property!(
@@ -43,7 +38,7 @@ fn test_device_decl_macros() {
     }
 
     unsafe impl ObjectType for DummyState {
-        type Class = DummyClass;
+        type Class = <DeviceState as ObjectType>::Class;
         const TYPE_NAME: &'static CStr = c_str!("dummy");
     }
 
@@ -61,8 +56,6 @@ fn test_device_decl_macros() {
         }
     }
 
-    impl_device_class!(DummyState);
-
     unsafe {
         module_call_init(module_init_type::MODULE_INIT_QOM);
         object_unref(object_new(DummyState::TYPE_NAME.as_ptr()).cast());