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| author | Paolo Bonzini <pbonzini@redhat.com> | 2024-10-29 15:00:26 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2024-12-19 19:36:37 +0100 |
| commit | cb36da9bd84076470f36da56542e85a2436e3d95 (patch) | |
| tree | 90d90f6debe5f234345a2781dc14329f92d00e9e /rust/qemu-api | |
| parent | 6dd818fbbbe3efc63889e7d811ac6b70e788c629 (diff) | |
| download | qemu-cb36da9bd84076470f36da56542e85a2436e3d95.zip qemu-cb36da9bd84076470f36da56542e85a2436e3d95.tar.gz qemu-cb36da9bd84076470f36da56542e85a2436e3d95.tar.bz2 | |
rust: qom: add possibility of overriding unparent
Add a blanket definition of ClassInitImpl<ObjectClass> that thunks
ObjectImpl::UNPARENT and overrides it in ObjectClass if it is not
None.
ClassInitImpl<DeviceClass> can now call its superclass's ClassInitImpl,
so that the C and Rust hierarchies match more closely.
This is mostly done as an example of implementing the metaclass
hierarchy under ClassInitImpl.
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'rust/qemu-api')
| -rw-r--r-- | rust/qemu-api/src/definitions.rs | 44 | ||||
| -rw-r--r-- | rust/qemu-api/src/device_class.rs | 6 |
2 files changed, 45 insertions, 5 deletions
diff --git a/rust/qemu-api/src/definitions.rs b/rust/qemu-api/src/definitions.rs index 13f8f6f..a2481c1 100644 --- a/rust/qemu-api/src/definitions.rs +++ b/rust/qemu-api/src/definitions.rs @@ -6,7 +6,7 @@ use std::{ffi::CStr, os::raw::c_void}; -use crate::bindings::{Object, ObjectClass, TypeInfo}; +use crate::bindings::{self, Object, ObjectClass, TypeInfo}; unsafe extern "C" fn rust_instance_init<T: ObjectImpl>(obj: *mut Object) { // SAFETY: obj is an instance of T, since rust_instance_init<T> @@ -121,6 +121,9 @@ pub trait ObjectImpl: ObjectType + ClassInitImpl<Self::Class> { class_data: core::ptr::null_mut(), interfaces: core::ptr::null_mut(), }; + + // methods on ObjectClass + const UNPARENT: Option<fn(&Self)> = None; } /// Internal trait used to automatically fill in a class struct. @@ -134,7 +137,8 @@ pub trait ObjectImpl: ObjectType + ClassInitImpl<Self::Class> { /// /// Each struct will implement this trait with `T` equal to each /// superclass. For example, a device should implement at least -/// `ClassInitImpl<`[`DeviceClass`](crate::bindings::DeviceClass)`>`. +/// `ClassInitImpl<`[`DeviceClass`](crate::bindings::DeviceClass)`>` and +/// `ClassInitImpl<`[`ObjectClass`](crate::bindings::ObjectClass)`>`. /// Such implementations are made in one of two ways. /// /// For most superclasses, `ClassInitImpl` is provided by the `qemu-api` @@ -147,9 +151,13 @@ pub trait ObjectImpl: ObjectType + ClassInitImpl<Self::Class> { /// ```ignore /// impl<T> ClassInitImpl<DeviceClass> for T /// where -/// T: DeviceImpl, +/// T: ClassInitImpl<ObjectClass> + DeviceImpl, /// ``` /// +/// The bound on `ClassInitImpl<ObjectClass>` is needed so that, +/// after initializing the `DeviceClass` part of the class struct, +/// the parent [`ObjectClass`] is initialized as well. +/// /// The other case is when manual implementation of the trait is needed. /// This covers the following cases: /// @@ -235,3 +243,33 @@ macro_rules! module_init { } }; } + +/// # Safety +/// +/// 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 { + assert!(!dev.is_null()); + let state = core::ptr::NonNull::new_unchecked(dev.cast::<T>()); + T::UNPARENT.unwrap()(state.as_ref()); + } +} + +impl<T> ClassInitImpl<ObjectClass> for T +where + T: ObjectImpl, +{ + fn class_init(oc: &mut ObjectClass) { + if <T as ObjectImpl>::UNPARENT.is_some() { + oc.unparent = Some(rust_unparent_fn::<T>); + } + } +} + +unsafe impl ObjectType for Object { + type Class = ObjectClass; + const TYPE_NAME: &'static CStr = + unsafe { CStr::from_bytes_with_nul_unchecked(bindings::TYPE_OBJECT) }; +} diff --git a/rust/qemu-api/src/device_class.rs b/rust/qemu-api/src/device_class.rs index dcec548..a9965d1 100644 --- a/rust/qemu-api/src/device_class.rs +++ b/rust/qemu-api/src/device_class.rs @@ -5,7 +5,7 @@ use std::ffi::CStr; use crate::{ - bindings::{self, DeviceClass, DeviceState, Error, Property, VMStateDescription}, + bindings::{self, DeviceClass, DeviceState, Error, ObjectClass, Property, VMStateDescription}, definitions::ClassInitImpl, prelude::*, }; @@ -68,7 +68,7 @@ unsafe extern "C" fn rust_reset_fn<T: DeviceImpl>(dev: *mut DeviceState) { impl<T> ClassInitImpl<DeviceClass> for T where - T: DeviceImpl, + T: ClassInitImpl<ObjectClass> + DeviceImpl, { fn class_init(dc: &mut DeviceClass) { if <T as DeviceImpl>::REALIZE.is_some() { @@ -88,6 +88,8 @@ where bindings::device_class_set_props_n(dc, prop.as_ptr(), prop.len()); } } + + <T as ClassInitImpl<ObjectClass>>::class_init(&mut dc.parent_class); } } |