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Date:   Wed, 04 Jan 2023 17:18:44 +0100
Message-Id: <CPJJIUQATXCL.D6C0EEMS35DV@vincent>
Cc:     "Miguel Ojeda" <ojeda@kernel.org>,
        "Alex Gaynor" <alex.gaynor@gmail.com>,
        "Boqun Feng" <boqun.feng@gmail.com>, "Gary Guo" <gary@garyguo.net>,
        =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>,
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 5/7] rust: sync: allow type of `self` to be
 `ArcBorrow<T>`
From:   "Vincenzo" <vincenzopalazzodev@gmail.com>
To:     "Wedson Almeida Filho" <wedsonaf@gmail.com>,
        <rust-for-linux@vger.kernel.org>
References: <20221228060346.352362-1-wedsonaf@gmail.com>
 <20221228060346.352362-5-wedsonaf@gmail.com>
In-Reply-To: <20221228060346.352362-5-wedsonaf@gmail.com>
Precedence: bulk


Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>

On Wed Dec 28, 2022 at 7:03 AM CET, Wedson Almeida Filho wrote:
> This allows associated functions whose `self` argument has
> `ArcBorrow<T>` as their type. This, in turn, allows callers to use the
> dot syntax to make calls.
>
> Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com>
> ---
>  rust/kernel/sync/arc.rs | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
>
> diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs
> index f68bfc02c81a..84f31c85a513 100644
> --- a/rust/kernel/sync/arc.rs
> +++ b/rust/kernel/sync/arc.rs
> @@ -255,11 +255,34 @@ impl<T: ?Sized> Drop for Arc<T> {
>  /// // Assert that both `obj` and `cloned` point to the same underlying =
object.
>  /// assert!(core::ptr::eq(&*obj, &*cloned));
>  /// ```
> +///
> +/// Using `ArcBorrow<T>` as the type of `self`:
> +///
> +/// ```
> +/// use crate::sync::{Arc, ArcBorrow};
> +///
> +/// struct Example {
> +///     a: u32,
> +///     b: u32,
> +/// }
> +///
> +/// impl Example {
> +///     fn use_reference(self: ArcBorrow<'_, Self>) {
> +///         // ...
> +///     }
> +/// }
> +///
> +/// let obj =3D Arc::try_new(Example { a: 10, b: 20 })?;
> +/// obj.as_arc_borrow().use_reference();
> +/// ```
>  pub struct ArcBorrow<'a, T: ?Sized + 'a> {
>      inner: NonNull<ArcInner<T>>,
>      _p: PhantomData<&'a ()>,
>  }
> =20
> +// This is to allow [`ArcBorrow`] (and variants) to be used as the type =
of `self`.
> +impl<T: ?Sized> core::ops::Receiver for ArcBorrow<'_, T> {}
> +
>  impl<T: ?Sized> Clone for ArcBorrow<'_, T> {
>      fn clone(&self) -> Self {
>          *self
> --=20
> 2.34.1