Re: [PATCH 4/7] xdiff: make fields of xrecord_t Rust friendly

From: Ezekiel Newren <ezekielnewren@gmail.com>
Date: Jul 28, 2025, 19:34 UTC
Message-ID: <CAH=ZcbCnEpBokM9rxmmkeM9GT948n7+RipXODHLfPssuwJuVCw@mail.gmail.com>
In-Reply-To: <91f6352f-abc4-4e99-938b-6a56aba2faed@gmail.com>

On Fri, Jul 18, 2025 at 7:35 AM Phillip Wood <phillip.wood123@gmail.com> wrote:

Show 14 quoted lines

>
> Hi Ezekiel
>
> On 17/07/2025 21:32, Ezekiel Newren via GitGitGadget wrote:
> > From: Ezekiel Newren <ezekielnewren@gmail.com>
> >
> > A few commits ago, we added definitions for Rust primitive types,
> > to facilitate interoperability between C and Rust. Switch a
> > few variables to use these types. Which, for now, will
> > require adding some casts.
>
> How necessary is it to change char' to 'u8' so long as the rust and C
> sides both use a type that is the same size? Also what's the advantage
> of using these typedefs rather than the normal C types like unit8_t ?

Rust defines char as 32 bits. C treats char as signed 8 bits. What git really means by char* is treat everything like a byte string, and u8 is how raw bytes are handled in Rust.

Show 13 quoted lines

> > diff --git a/xdiff/xdiffi.c b/xdiff/xdiffi.c
> > index 5a96e36dfbea..3b364c61f671 100644
> > --- a/xdiff/xdiffi.c
> > +++ b/xdiff/xdiffi.c
> > @@ -418,7 +418,7 @@ static int get_indent(xrecord_t *rec)
> >       long i;
> >       int ret = 0;
> >
> > -     for (i = 0; i < rec->size; i++) {
> > +     for (i = 0; i < (long) rec->size; i++) {
>
> i is a loop counter and array index so we can lose this cast by
> changeing i to size_t

Ok, but I'm going to change the type of i to usize and stuff it inside the loop i.e. for (usize i = 0; ...

> Thanks
>
> Phillip