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