> > +#[doc(alias = "VMSTATE_VALIDATE")]
> > +#[macro_export]
> > +macro_rules! vmstate_validate {
> > + ($struct_name:ty, $test_name:expr, $test_fn:expr $(,)?) => {
> > + $crate::bindings::VMStateField {
> > + name: ::std::ffi::CStr::as_ptr($test_name),
> > + // TODO: Use safe callback.
>
> Why is the TODO still there?
I forgot to delete this comment...
> > + field_exists: {
> > + const fn test_cb_builder__<
> > + T,
> > + F: for<'a> $crate::callbacks::FnCall<(&'a T, u8),
> > bool>,
> > + >(
> > + _phantom: ::core::marker::PhantomData<F>,
> > + ) -> $crate::vmstate::VMSFieldExistCb {
> > + let _: () = F::ASSERT_IS_SOME;
> > + $crate::vmstate::rust_vms_test_field_exists::<T, F>
> > + }
> > +
> > + const fn phantom__<T>(_: &T) ->
> > ::core::marker::PhantomData<T> {
> > + ::core::marker::PhantomData
> > + }
> > + Some(test_cb_builder__::<$struct_name,
> > _>(phantom__(&$test_fn)))
> > + },
> > + ..$crate::zeroable::Zeroable::ZERO
> > + }
> > + .with_exist_check()
> > + };
>
> Would it be possible, or make sense, to move most of the code for
> field_exists inside .with_exist_check()?
>
If so, the method would be like:
pub fn with_exist_check<T, F>(
mut self,
_cb: F
) -> Self
where
F: for<'a> FnCall<(&'a T, u8), bool>,
Then the use case could be like:
vmstate_struct!(HPETState, timers[0 .. num_timers], &VMSTATE_HPET_TIMER,
BqlRefCell<HPETTimer>).with_exist_check<HPETState, _>(foo_field_check),
Here we need to specify the structure type in with_exist_check, though it's
already specified in vmstate_struct as the first field.
In this way, I understand with_exist_check() doesn't need phantom__()
trick.
Instead, (after I dropped the few patches you mentioned,) now vmstate_of
& vmstate_struct could accept the optional "test_fn" field (luckily, at
least test_fn can still be parsed!), then the example would be:
vmstate_struct!(HPETState, timers[0 .. num_timers], &VMSTATE_HPET_TIMER,
BqlRefCell<HPETTimer>, foo_field_check)
And in this way, phantom__() is necessary.
So I think the main issue is the format, which do you prefer?
Thanks,
Zhao
