From 33aa660575f7174752a7308229e5fc108921c2a6 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 11 Dec 2024 10:33:31 +0100 Subject: [PATCH] rust: qom: automatically use Drop trait to implement instance_finalize Replace the customizable INSTANCE_FINALIZE with a generic function that drops the Rust object. Reviewed-by: Zhao Liu Signed-off-by: Paolo Bonzini --- rust/qemu-api/src/qom.rs | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/rust/qemu-api/src/qom.rs b/rust/qemu-api/src/qom.rs index 40d17a92e1..b0332ba247 100644 --- a/rust/qemu-api/src/qom.rs +++ b/rust/qemu-api/src/qom.rs @@ -180,6 +180,16 @@ unsafe extern "C" fn rust_class_init>( T::class_init(unsafe { &mut *klass.cast::() }) } +unsafe extern "C" fn drop_object(obj: *mut Object) { + // SAFETY: obj is an instance of T, since drop_object 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 + // superclass field separately after this function returns, `T` must + // implement the unsafe trait ObjectType; the safety rules for the + // trait mandate that the parent field is manually dropped. + unsafe { std::ptr::drop_in_place(obj.cast::()) } +} + /// Trait exposed by all structs corresponding to QOM objects. /// /// # Safety @@ -442,7 +452,6 @@ pub trait ObjectImpl: ObjectType + ClassInitImpl { /// Whether the object can be instantiated const ABSTRACT: bool = false; - const INSTANCE_FINALIZE: Option = None; /// Function that is called to initialize an object. The parent class will /// have already been initialized so the type is only responsible for @@ -478,7 +487,7 @@ pub trait ObjectImpl: ObjectType + ClassInitImpl { None => None, Some(_) => Some(rust_instance_post_init::), }, - instance_finalize: Self::INSTANCE_FINALIZE, + instance_finalize: Some(drop_object::), abstract_: Self::ABSTRACT, class_size: core::mem::size_of::(), class_init: Some(rust_class_init::), -- 2.39.5