rust: prefer NonNull::new to assertions

Do not use new_unchecked; the effect is the same, but the
code is easier to read and unsafe regions become smaller.
Likewise, NonNull::new can be used instead of assertion and
followed by as_ref() or as_mut() instead of dereferencing the
pointer.

Suggested-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2025-01-23 11:25:22 +01:00
parent 24f0e8d818
commit 7d0520398f
5 changed files with 35 additions and 47 deletions

View file

@ -4,7 +4,7 @@
//! Bindings to create devices and access device functionality from Rust.
use std::ffi::CStr;
use std::{ffi::CStr, ptr::NonNull};
pub use bindings::{DeviceClass, DeviceState, Property};
@ -55,9 +55,8 @@ pub trait DeviceImpl {
/// 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_realize_fn<T: DeviceImpl>(dev: *mut DeviceState, _errp: *mut *mut Error) {
assert!(!dev.is_null());
let state = dev.cast::<T>();
T::REALIZE.unwrap()(unsafe { &mut *state });
let state = NonNull::new(dev).unwrap().cast::<T>();
T::REALIZE.unwrap()(unsafe { state.as_ref() });
}
/// # Safety
@ -66,9 +65,8 @@ unsafe extern "C" fn rust_realize_fn<T: DeviceImpl>(dev: *mut DeviceState, _errp
/// 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_reset_fn<T: DeviceImpl>(dev: *mut DeviceState) {
assert!(!dev.is_null());
let state = dev.cast::<T>();
T::RESET.unwrap()(unsafe { &mut *state });
let mut state = NonNull::new(dev).unwrap().cast::<T>();
T::RESET.unwrap()(unsafe { state.as_mut() });
}
impl<T> ClassInitImpl<DeviceClass> for T