If we define the same function name twice in a trait (using `#[cfg]`),
the `vtable` macro will redefine its `gen_const_name`, e.g. this will
define `HAS_BAR` twice:
#[vtable]
pub trait Foo {
#[cfg(CONFIG_X)]
fn bar();
#[cfg(not(CONFIG_X))]
fn bar(x: usize);
}
Fixes: b44becc5ee ("rust: macros: add `#[vtable]` proc macro")
Signed-off-by: Qingsong Chen <changxian.cqs@antgroup.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Sergio González Collado <sergio.collado@gmail.com>
Link: https://lore.kernel.org/r/20230808025404.2053471-1-changxian.cqs@antgroup.com
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>
