Currently, we generate `HAS_` constants as long as the definition exists in
the source, regardless if it is cfg-ed out or not.
Currently, uses of `#[cfg]` present in both trait and impl, so it is not a
problem; however if only the impl side uses `#[cfg]` then `HAS_` constants
will incorrectly be true while it shouldnt't.
With `syn` support, we can now implement `#[cfg]` handling properly by
propagating the `#[cfg]` attributes to the constants.
Signed-off-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Link: https://patch.msgid.link/20260113170529.2240744-1-gary@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
With `quote` crate now vendored in the kernel, we can remove our custom
`quote!` macro implementation and just rely on that crate instead.
The `quote` crate uses types from the `proc-macro2` library so we also
update to use that, and perform conversion in the top-level lib.rs.
Clippy complains about unnecessary `.to_string()` as `proc-macro2`
provides additional `PartialEq` impl, so they are removed.
Reviewed-by: Tamir Duberstein <tamird@gmail.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Gary Guo <gary@garyguo.net>
Acked-by: David Gow <davidgow@google.com> # for kunit
Link: https://patch.msgid.link/20260112170919.1888584-3-gary@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This procedural macro attribute provides a simple way to declare
a trait with a set of operations that later users can partially
implement, providing compile-time `HAS_*` boolean associated
constants that indicate whether a particular operation was overridden.
This is useful as the Rust counterpart to structs like
`file_operations` where some pointers may be `NULL`, indicating
an operation is not provided.
For instance:
#[vtable]
trait Operations {
fn read(...) -> Result<usize> {
Err(EINVAL)
}
fn write(...) -> Result<usize> {
Err(EINVAL)
}
}
#[vtable]
impl Operations for S {
fn read(...) -> Result<usize> {
...
}
}
assert_eq!(<S as Operations>::HAS_READ, true);
assert_eq!(<S as Operations>::HAS_WRITE, false);
Signed-off-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Sergio González Collado <sergio.collado@gmail.com>
[Reworded, adapted for upstream and applied latest changes]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
