From 92a655ae00a2f15fdd80eb96cd23526c0d8f0bfd Mon Sep 17 00:00:00 2001
From: Wedson Almeida Filho <wedsonaf@gmail.com>
Date: Wed, 28 Dec 2022 06:03:44 +0000
Subject: rust: sync: allow type of `self` to be `ArcBorrow<T>`

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>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Acked-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 rust/kernel/sync/arc.rs | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

(limited to 'rust')

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 = 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 ()>,
 }
 
+// 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
-- 
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