Re: [PATCH 1/4] rust: alloc: implement `Borrow` and `BorrowMut` for `Vec`

["Alexandre Courbot" <acourbot@nvidia.com>]

Hi Benno,

On Mon Jun 2, 2025 at 1:11 AM JST, Benno Lossin wrote:
> On Sun Jun 1, 2025 at 5:00 AM CEST, Alexandre Courbot wrote:
>> Implement these two common traits, which allow generic types to store
>> either an owned value or a reference to it.
>
> I don't understand the second part of the sentence.

I want to say that Borrow allows you to do something like:

    struct Foo<B: Borrow<u32>>(B);

    // `foo1` owns its value...
    let foo1 = Foo(0x12);

    let i = 0x24;
    // ... but `foo2` just borrows it, subject to the lifetime of `i`.
    let foo2 = Foo(&i);

And the implementations in this series also let you do:

    // `foo3`'s value is owned, but heap-allocated
    let foo3 = Arc::new(KBox::new(0x56, GFP_KERNEL)?);

    let j = Arc::new(0x78, GFP_KERNEL)?;
    // `foo4`'s value is shared and its lifetime runtime-managed.
    let foo4 = Foo(j.clone());