bianbu-linux-6.6/rust/kernel/prelude.rs
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

24 lines
528 B
Rust

// SPDX-License-Identifier: GPL-2.0
//! The `kernel` prelude.
//!
//! These are the most common items used by Rust code in the kernel,
//! intended to be imported by all Rust code, for convenience.
//!
//! # Examples
//!
//! ```
//! use kernel::prelude::*;
//! ```
pub use core::pin::Pin;
pub use alloc::{boxed::Box, vec::Vec};
pub use macros::{module, vtable};
pub use super::{pr_alert, pr_crit, pr_debug, pr_emerg, pr_err, pr_info, pr_notice, pr_warn};
pub use super::error::{Error, Result};
pub use super::ThisModule;