Re: [PATCH] rust: alloc: Add doctest for `ArrayLayout`

[Alice Ryhl]

On Tue, Dec 3, 2024 at 6:19 AM <jtostler1@xxxxxxxxx> wrote:
>
> From: Jimmy Ostler <jtostler1@xxxxxxxxx>
>
> Added a rustdoc example and Kunit test to the `ArrayLayout` struct's
> `ArrayLayout::new()` function.
>
> Kunit tests ran using `./tools/testing/kunit/kunit.py run \
> --make_options LLVM=1 \
> --kconfig_add CONFIG_RUST=y` passed.
>
> Generated documentation looked as expected.
>
> Signed-off-by: Jimmy Ostler <jtostler1@xxxxxxxxx>
> Suggested-by: Boqun Feng <boqun.feng@xxxxxxxxx>
> Link: https://github.com/Rust-for-Linux/linux/issues/1131
> ---
>  rust/kernel/alloc/layout.rs | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>
> diff --git a/rust/kernel/alloc/layout.rs b/rust/kernel/alloc/layout.rs
> index 4b3cd7fdc816..4265f92f8af0 100644
> --- a/rust/kernel/alloc/layout.rs
> +++ b/rust/kernel/alloc/layout.rs
> @@ -7,6 +7,7 @@
>  use core::{alloc::Layout, marker::PhantomData};
>
>  /// Error when constructing an [`ArrayLayout`].
> +#[derive(Debug)]
>  pub struct LayoutError;
>
>  /// A layout for an array `[T; n]`.
> @@ -43,6 +44,19 @@ pub const fn empty() -> Self {
>      /// # Errors
>      ///
>      /// When `len * size_of::<T>()` overflows or when `len * size_of::<T>() > isize::MAX`.
> +    ///
> +    ///
> +    /// # Examples

There should only be one empty line before # Examples, not two.

> +    ///
> +    /// ```rust
> +    /// use kernel::alloc::layout::ArrayLayout;
> +    ///
> +    /// let layout = ArrayLayout::<i32>::new(15);
> +    /// assert_eq!(layout.len(), 15);

I think it's less confusing to move this expect() to the line before.
let layout = ArrayLayout::<i32>::new(15).expect(...);

> +    ///
> +    /// let layout = ArrayLayout::<i32>::new(isize::MAX as usize);
> +    /// assert!(layout.is_err());
> +    /// ```
>      pub const fn new(len: usize) -> Result<Self, LayoutError> {
>          match len.checked_mul(core::mem::size_of::<T>()) {
>              Some(size) if size <= ISIZE_MAX => {
>
> base-commit: 1dc707e647bc919834eff9636c8d00b78c782545
> --
> 2.47.1
>
>