linux/rust/macros
Gary Guo b44becc5ee rust: macros: add #[vtable] proc macro
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>
2022-12-04 01:59:15 +01:00
..
concat_idents.rs rust: macros: add concat_idents! proc macro 2022-12-04 01:59:04 +01:00
helpers.rs
lib.rs rust: macros: add #[vtable] proc macro 2022-12-04 01:59:15 +01:00
module.rs
vtable.rs rust: macros: add #[vtable] proc macro 2022-12-04 01:59:15 +01:00