rust: qom: wrap Object with Opaque<>

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

rust/qemu-api/src/bindings.rs

@@ -46,9 +46,6 @@ unsafe impl Sync for MemoryRegion {}
 unsafe impl Send for ObjectClass {}
 unsafe impl Sync for ObjectClass {}
 
-unsafe impl Send for Object {}
-unsafe impl Sync for Object {}
-
 unsafe impl Send for SysBusDevice {}
 unsafe impl Sync for SysBusDevice {}
 

rust/qemu-api/src/memory.rs

@@ -157,7 +157,7 @@ impl MemoryRegion {
             let cstr = CString::new(name).unwrap();
             memory_region_init_io(
                 slot,
-                owner.cast::<Object>(),
+                owner.cast::<bindings::Object>(),
                 ops,
                 owner.cast::<c_void>(),
                 cstr.as_ptr(),

rust/qemu-api/src/qdev.rs

@@ -52,7 +52,7 @@ pub trait ResettablePhasesImpl {
 /// can be downcasted to type `T`. We also expect the device is
 /// readable/writeable from one thread at any time.
 unsafe extern "C" fn rust_resettable_enter_fn<T: ResettablePhasesImpl>(
-    obj: *mut Object,
+    obj: *mut bindings::Object,
     typ: ResetType,
 ) {
     let state = NonNull::new(obj).unwrap().cast::<T>();
@@ -65,7 +65,7 @@ unsafe extern "C" fn rust_resettable_enter_fn<T: ResettablePhasesImpl>(
 /// can be downcasted to type `T`. We also expect the device is
 /// readable/writeable from one thread at any time.
 unsafe extern "C" fn rust_resettable_hold_fn<T: ResettablePhasesImpl>(
-    obj: *mut Object,
+    obj: *mut bindings::Object,
     typ: ResetType,
 ) {
     let state = NonNull::new(obj).unwrap().cast::<T>();
@@ -78,7 +78,7 @@ unsafe extern "C" fn rust_resettable_hold_fn<T: ResettablePhasesImpl>(
 /// can be downcasted to type `T`. We also expect the device is
 /// readable/writeable from one thread at any time.
 unsafe extern "C" fn rust_resettable_exit_fn<T: ResettablePhasesImpl>(
-    obj: *mut Object,
+    obj: *mut bindings::Object,
     typ: ResetType,
 ) {
     let state = NonNull::new(obj).unwrap().cast::<T>();

rust/qemu-api/src/qom.rs

@@ -101,16 +101,24 @@ use std::{
     ptr::NonNull,
 };
 
-pub use bindings::{Object, ObjectClass};
+pub use bindings::ObjectClass;
 
 use crate::{
     bindings::{
         self, object_class_dynamic_cast, object_dynamic_cast, object_get_class,
         object_get_typename, object_new, object_ref, object_unref, TypeInfo,
     },
-    cell::bql_locked,
+    cell::{bql_locked, Opaque},
 };
 
+/// A safe wrapper around [`bindings::Object`].
+#[repr(transparent)]
+#[derive(Debug, qemu_api_macros::Wrapper)]
+pub struct Object(Opaque<bindings::Object>);
+
+unsafe impl Send for Object {}
+unsafe impl Sync for Object {}
+
 /// Marker trait: `Self` can be statically upcasted to `P` (i.e. `P` is a direct
 /// or indirect parent of `Self`).
 ///
@@ -199,7 +207,7 @@ impl<T: fmt::Display + ObjectType> fmt::Display for ParentField<T> {
     }
 }
 
-unsafe extern "C" fn rust_instance_init<T: ObjectImpl>(obj: *mut Object) {
+unsafe extern "C" fn rust_instance_init<T: ObjectImpl>(obj: *mut bindings::Object) {
     let mut state = NonNull::new(obj).unwrap().cast::<T>();
     // SAFETY: obj is an instance of T, since rust_instance_init<T>
     // is called from QOM core as the instance_init function
@@ -209,7 +217,7 @@ unsafe extern "C" fn rust_instance_init<T: ObjectImpl>(obj: *mut Object) {
     }
 }
 
-unsafe extern "C" fn rust_instance_post_init<T: ObjectImpl>(obj: *mut Object) {
+unsafe extern "C" fn rust_instance_post_init<T: ObjectImpl>(obj: *mut bindings::Object) {
     let state = NonNull::new(obj).unwrap().cast::<T>();
     // SAFETY: obj is an instance of T, since rust_instance_post_init<T>
     // is called from QOM core as the instance_post_init function
@@ -230,7 +238,7 @@ unsafe extern "C" fn rust_class_init<T: ObjectType + ObjectImpl>(
     <T as ObjectImpl>::CLASS_INIT(unsafe { klass.as_mut() })
 }
 
-unsafe extern "C" fn drop_object<T: ObjectImpl>(obj: *mut Object) {
+unsafe extern "C" fn drop_object<T: ObjectImpl>(obj: *mut bindings::Object) {
     // SAFETY: obj is an instance of T, since drop_object<T> is called
     // from the QOM core function object_deinit() as the instance_finalize
     // function for class T.  Note that while object_deinit() will drop the
@@ -280,14 +288,14 @@ pub unsafe trait ObjectType: Sized {
     /// Return the receiver as an Object.  This is always safe, even
     /// if this type represents an interface.
     fn as_object(&self) -> &Object {
-        unsafe { &*self.as_object_ptr() }
+        unsafe { &*self.as_ptr().cast() }
     }
 
     /// Return the receiver as a const raw pointer to Object.
     /// This is preferrable to `as_object_mut_ptr()` if a C
     /// function only needs a `const Object *`.
-    fn as_object_ptr(&self) -> *const Object {
+    fn as_object_ptr(&self) -> *const bindings::Object {
-        self.as_ptr().cast()
+        self.as_object().as_ptr()
     }
 
     /// Return the receiver as a mutable raw pointer to Object.
@@ -297,8 +305,8 @@ pub unsafe trait ObjectType: Sized {
     /// This cast is always safe, but because the result is mutable
     /// and the incoming reference is not, this should only be used
     /// for calls to C functions, and only if needed.
-    unsafe fn as_object_mut_ptr(&self) -> *mut Object {
+    unsafe fn as_object_mut_ptr(&self) -> *mut bindings::Object {
-        self.as_object_ptr() as *mut _
+        self.as_object().as_mut_ptr()
     }
 }
 
@@ -621,7 +629,7 @@ pub trait ObjectImpl: ObjectType + IsA<Object> {
 /// We expect the FFI user of this function to pass a valid pointer that
 /// can be downcasted to type `T`. We also expect the device is
 /// readable/writeable from one thread at any time.
-unsafe extern "C" fn rust_unparent_fn<T: ObjectImpl>(dev: *mut Object) {
+unsafe extern "C" fn rust_unparent_fn<T: ObjectImpl>(dev: *mut bindings::Object) {
     let state = NonNull::new(dev).unwrap().cast::<T>();
     T::UNPARENT.unwrap()(unsafe { state.as_ref() });
 }
@@ -796,8 +804,9 @@ pub trait ObjectClassMethods: IsA<Object> {
         // SAFETY: the object created by object_new is allocated on
         // the heap and has a reference count of 1
         unsafe {
-            let obj = &*object_new(Self::TYPE_NAME.as_ptr());
+            let raw_obj = object_new(Self::TYPE_NAME.as_ptr());
-            Owned::from_raw(obj.unsafe_cast::<Self>())
+            let obj = Object::from_raw(raw_obj).unsafe_cast::<Self>();
+            Owned::from_raw(obj)
         }
     }
 }