rust: qdev: move device_class_init! body to generic function, ClassInitImpl implementation to macro

Use a trait to access the former parameters to device_class_init!.
This allows hiding the details of the class_init implementation behind
a generic function and makes higher-level functionality available from
qemu_api.

The implementation of ClassInitImpl is then the same for all devices and
is easily macroized.  Later on, we can remove the need to implement
ClassInitImpl by hand for all device types, and stop making
rust_device_class_init<>() public.

While at it, document the members of DeviceImpl.

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

1 files changed, 13 insertions, 17 deletions

diff --git a/rust/qemu-api/tests/tests.rs b/rust/qemu-api/tests/tests.rs
index fd0c979..b8b12a4 100644
--- a/rust/qemu-api/tests/tests.rs
+++ b/rust/qemu-api/tests/tests.rs
@@ -2,13 +2,14 @@
 // Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
 // SPDX-License-Identifier: GPL-2.0-or-later
 
-use std::{ffi::CStr, os::raw::c_void};
+use std::ffi::CStr;
 
 use qemu_api::{
     bindings::*,
     c_str, declare_properties, define_property,
-    definitions::{ClassInitImpl, ObjectImpl},
-    device_class, device_class_init,
+    definitions::ObjectImpl,
+    device_class::{self, DeviceImpl},
+    impl_device_class,
     zeroable::Zeroable,
 };
 
@@ -45,28 +46,23 @@ fn test_device_decl_macros() {
             ),
     }
 
-    device_class_init! {
-        dummy_class_init,
-        props => DUMMY_PROPERTIES,
-        realize_fn => None,
-        legacy_reset_fn => None,
-        vmsd => VMSTATE,
-    }
-
     impl ObjectImpl for DummyState {
         type Class = DummyClass;
         const TYPE_NAME: &'static CStr = c_str!("dummy");
         const PARENT_TYPE_NAME: Option<&'static CStr> = Some(device_class::TYPE_DEVICE);
     }
 
-    impl ClassInitImpl for DummyState {
-        const CLASS_INIT: Option<unsafe extern "C" fn(klass: *mut ObjectClass, data: *mut c_void)> =
-            Some(dummy_class_init);
-        const CLASS_BASE_INIT: Option<
-            unsafe extern "C" fn(klass: *mut ObjectClass, data: *mut c_void),
-        > = None;
+    impl DeviceImpl for DummyState {
+        fn properties() -> &'static [Property] {
+            &DUMMY_PROPERTIES
+        }
+        fn vmsd() -> Option<&'static VMStateDescription> {
+            Some(&VMSTATE)
+        }
     }
 
+    impl_device_class!(DummyState);
+
     unsafe {
         module_call_init(module_init_type::MODULE_INIT_QOM);
         object_unref(object_new(DummyState::TYPE_NAME.as_ptr()).cast());