From: "brian m. carlson" <sandals@crustytoothpaste•net>
To: Taylor Blau <me@ttaylorr•com>
Cc: Ezekiel Newren via GitGitGadget <gitgitgadget@gmail•com>,
git@vger•kernel.org, Elijah Newren <newren@gmail•com>,
Ezekiel Newren <ezekielnewren@gmail•com>
Subject: Re: [PATCH 4/7] xdiff: make fields of xrecord_t Rust friendly
Date: Thu, 17 Jul 2025 23:13:14 +0000 [thread overview]
Message-ID: <aHmDiqsBsDJJ6m8C@fruit.crustytoothpaste.net> (raw)
In-Reply-To: <aHl9YLc823uWwgIp@nand.local>
[-- Attachment #1: Type: text/plain, Size: 2447 bytes --]
On 2025-07-17 at 22:46:56, Taylor Blau wrote:
> On Thu, Jul 17, 2025 at 08:32:21PM +0000, 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.
>
> Hmm, interesting. I am not super familiar with how people typically
> handle interoperability between C and Rust, but having to change types
> on the C side to make it work with Rust is a bit surprising to me.
>
> I would have expected that the Rust side would have declared its types
> using libc::c_int, libc::size_t, and so on. I think I have a vague
> preference towards putting the burden of casting on the Rust side, but,
> again, I am not super familiar with how transitions like these are
> typically approached.
Rust normally handles byte strings as slices or vectors of u8 (that is,
C's uint8_t). C handles them as char, which may or may not be unsigned,
as we all know, which leads to some "entertaining" problems from time to
time.
Also, in general, Rust doesn't offer generic system-specific types, such
as `long`, except for C FFI. This is actually a strong benefit, since
it means we're not inclined to write `unsigned long` and then wonder why
things are broken on Windows: instead, we write either `usize` (the
equivalent of `size_t`) or `u64` (for things like file sizes). This is
much more ingrained than it is in Go, which has a tendency to use `int`
(Rust's `isize`) a lot and much less often specific types.
If we're going to move this code entirely into Rust, then it makes sense
to cast temporarily, and I'm fine doing that in C, since it's C that has
the weird system-dependent behaviour (arbitrary decisions on the
signedness of char). That actually allows us to have more confidence in
the safety and maintainability of the Rust code since it is less system
dependent and leave the suspect pieces in C. It may also, interestingly
enough, also allow us to easily get rid of the weird 2 GB limit on diffs
due to the unpleasant dependency on `int` in the xdiff code, which I
would absolutely love to see.
However, I'm not dead set against casting in Rust if that's what
everyone else wants instead.
--
brian m. carlson (they/them)
Toronto, Ontario, CA
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next prev parent reply other threads:[~2025-07-17 23:13 UTC|newest]
Thread overview: 204+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-17 20:32 [PATCH 0/7] RFC: Accelerate xdiff and begin its rustification Ezekiel Newren via GitGitGadget
2025-07-17 20:32 ` [PATCH 1/7] xdiff: introduce rust Ezekiel Newren via GitGitGadget
2025-07-17 21:30 ` brian m. carlson
2025-07-17 21:54 ` Junio C Hamano
2025-07-17 22:39 ` Taylor Blau
2025-07-18 23:15 ` Ezekiel Newren
2025-07-23 21:57 ` brian m. carlson
2025-07-23 22:26 ` Junio C Hamano
2025-07-28 19:11 ` Ezekiel Newren
2025-07-31 22:37 ` brian m. carlson
2025-07-22 22:02 ` Mike Hommey
2025-07-22 23:52 ` brian m. carlson
2025-07-17 22:38 ` Taylor Blau
2025-07-17 20:32 ` [PATCH 2/7] xdiff/xprepare: remove superfluous forward declarations Ezekiel Newren via GitGitGadget
2025-07-17 22:41 ` Taylor Blau
2025-07-17 20:32 ` [PATCH 3/7] xdiff: delete unnecessary fields from xrecord_t and xdfile_t Ezekiel Newren via GitGitGadget
2025-07-17 20:32 ` [PATCH 4/7] xdiff: make fields of xrecord_t Rust friendly Ezekiel Newren via GitGitGadget
2025-07-17 22:46 ` Taylor Blau
2025-07-17 23:13 ` brian m. carlson [this message]
2025-07-17 23:37 ` Elijah Newren
2025-07-18 0:23 ` Taylor Blau
2025-07-18 0:21 ` Taylor Blau
2025-07-18 13:35 ` Phillip Wood
2025-07-28 19:34 ` Ezekiel Newren
2025-07-28 19:52 ` Phillip Wood
2025-07-28 20:14 ` Ezekiel Newren
2025-07-31 14:20 ` Phillip Wood
2025-07-31 20:58 ` Ezekiel Newren
2025-08-01 9:14 ` Phillip Wood
2025-07-28 20:53 ` Junio C Hamano
2025-07-28 20:00 ` Collin Funk
2025-07-20 1:39 ` Johannes Schindelin
2025-07-17 20:32 ` [PATCH 5/7] xdiff: separate parsing lines from hashing them Ezekiel Newren via GitGitGadget
2025-07-17 22:59 ` Taylor Blau
2025-07-18 13:34 ` Phillip Wood
2025-07-17 20:32 ` [PATCH 6/7] xdiff: conditionally use Rust's implementation of xxhash Ezekiel Newren via GitGitGadget
2025-07-17 23:29 ` Taylor Blau
2025-07-18 19:00 ` Junio C Hamano
2025-07-31 21:13 ` Ezekiel Newren
2025-08-02 7:53 ` Matthias Aßhauer
2025-07-19 21:53 ` Johannes Schindelin
2025-07-20 10:14 ` Phillip Wood
2025-09-23 9:57 ` gitoxide-compatible licensing of Git's Rust code, was " Johannes Schindelin
2025-09-23 17:48 ` Jeff King
2025-09-24 13:48 ` Phillip Wood
2025-09-25 2:25 ` Jeff King
2025-09-25 5:42 ` Patrick Steinhardt
2025-09-26 10:06 ` Phillip Wood
2025-10-03 3:18 ` Jeff King
2025-10-03 9:51 ` Phillip Wood
2025-10-07 9:11 ` Patrick Steinhardt
2025-11-17 13:37 ` Johannes Schindelin
2025-10-05 5:32 ` Yee Cheng Chin
2025-07-17 20:32 ` [PATCH 7/7] github_workflows: install rust Ezekiel Newren via GitGitGadget
2025-07-17 21:23 ` brian m. carlson
2025-07-18 23:01 ` Ezekiel Newren
2025-07-25 23:56 ` Ben Knoble
2025-07-19 21:54 ` Johannes Schindelin
2025-07-17 21:51 ` [PATCH 0/7] RFC: Accelerate xdiff and begin its rustification brian m. carlson
2025-07-17 22:25 ` Taylor Blau
2025-07-18 0:29 ` brian m. carlson
2025-07-22 12:21 ` Patrick Steinhardt
2025-07-22 15:56 ` Junio C Hamano
2025-07-22 16:03 ` Sam James
2025-07-22 21:37 ` Elijah Newren
2025-07-22 21:55 ` Sam James
2025-07-22 22:08 ` Collin Funk
2025-07-18 9:23 ` Christian Brabandt
2025-07-18 16:26 ` Junio C Hamano
2025-07-19 0:32 ` Elijah Newren
2025-07-18 13:34 ` Phillip Wood
2025-07-18 21:25 ` Eli Schwartz
2025-07-19 0:48 ` Haelwenn (lanodan) Monnier
2025-07-22 12:21 ` Patrick Steinhardt
2025-07-22 14:24 ` Patrick Steinhardt
2025-07-22 15:14 ` Eli Schwartz
2025-07-22 15:56 ` Sam James
2025-07-23 4:32 ` Patrick Steinhardt
2025-07-24 9:01 ` Pierre-Emmanuel Patry
2025-07-24 10:00 ` Patrick Steinhardt
2025-07-28 9:06 ` Pierre-Emmanuel Patry
2025-07-18 14:38 ` Junio C Hamano
2025-07-18 21:56 ` Ezekiel Newren
2025-07-21 10:14 ` Phillip Wood
2025-07-21 18:33 ` Junio C Hamano
2025-07-19 21:53 ` Johannes Schindelin
2025-07-20 8:45 ` Matthias Aßhauer
2025-08-15 1:22 ` [PATCH v2 00/17] " Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 01/17] doc: add a policy for using Rust brian m. carlson via GitGitGadget
2025-08-15 17:03 ` Matthias Aßhauer
2025-08-15 21:31 ` Junio C Hamano
2025-08-16 8:06 ` Matthias Aßhauer
2025-08-19 2:06 ` Ezekiel Newren
2025-08-15 1:22 ` [PATCH v2 02/17] xdiff: introduce rust Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 03/17] xdiff/xprepare: remove superfluous forward declarations Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 04/17] xdiff: delete unnecessary fields from xrecord_t and xdfile_t Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 05/17] xdiff: make fields of xrecord_t Rust friendly Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 06/17] xdiff: separate parsing lines from hashing them Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 07/17] xdiff: conditionally use Rust's implementation of xxhash Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 08/17] github workflows: install rust Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 09/17] Do support Windows again after requiring Rust Johannes Schindelin via GitGitGadget
2025-08-15 17:12 ` Matthias Aßhauer
2025-08-15 21:48 ` Junio C Hamano
2025-08-15 22:11 ` Johannes Schindelin
2025-08-15 23:37 ` Junio C Hamano
2025-08-15 23:37 ` Junio C Hamano
2025-08-16 8:53 ` Matthias Aßhauer
2025-08-17 15:57 ` Junio C Hamano
2025-08-19 2:22 ` Ezekiel Newren
2025-08-15 1:22 ` [PATCH v2 10/17] win+Meson: allow for xdiff to be compiled with MSVC Johannes Schindelin via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 11/17] win+Meson: do allow linking with the Rust-built xdiff Johannes Schindelin via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 12/17] github workflows: define rust versions and targets in the same place Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 13/17] github workflows: upload Cargo.lock Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 14/17] xdiff: implement a white space iterator in Rust Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 15/17] xdiff: create line_hash() and line_equal() Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 16/17] xdiff: optimize case where --ignore-cr-at-eol is the only whitespace flag Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 17/17] xdiff: use rust's version of whitespace processing Ezekiel Newren via GitGitGadget
2025-08-15 15:07 ` [-SPAM-] [PATCH v2 00/17] RFC: Accelerate xdiff and begin its rustification Ramsay Jones
2025-08-19 2:00 ` Elijah Newren
2025-08-24 16:52 ` Patrick Steinhardt
2025-08-18 22:31 ` Junio C Hamano
2025-08-18 23:52 ` Ben Knoble
2025-08-19 1:52 ` Elijah Newren
2025-08-19 9:47 ` Junio C Hamano
2025-08-23 3:55 ` [PATCH v3 00/15] RFC: Cleanup " Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 01/15] doc: add a policy for using Rust brian m. carlson via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 02/15] xdiff: introduce rust Ezekiel Newren via GitGitGadget
2025-08-23 13:43 ` rsbecker
2025-08-23 14:26 ` Kristoffer Haugsbakk
2025-08-23 15:06 ` rsbecker
2025-08-23 18:30 ` Elijah Newren
2025-08-23 19:24 ` brian m. carlson
2025-08-23 20:04 ` rsbecker
2025-08-23 20:36 ` Sam James
2025-08-23 21:17 ` Haelwenn (lanodan) Monnier
2025-08-27 1:57 ` Taylor Blau
2025-08-27 14:39 ` rsbecker
2025-08-27 17:06 ` Junio C Hamano
2025-08-27 17:15 ` rsbecker
2025-08-27 20:12 ` Taylor Blau
2025-08-27 20:22 ` Junio C Hamano
2025-09-02 11:16 ` Patrick Steinhardt
2025-09-02 11:30 ` Sam James
2025-09-02 17:27 ` brian m. carlson
2025-09-02 18:47 ` Sam James
2025-09-03 18:22 ` Collin Funk
2025-09-03 5:40 ` Patrick Steinhardt
2025-09-03 16:22 ` Ramsay Jones
2025-09-03 22:10 ` Junio C Hamano
2025-09-03 22:48 ` Josh Steadmon
2025-09-04 11:10 ` Patrick Steinhardt
2025-09-04 15:45 ` Junio C Hamano
2025-09-05 8:23 ` Patrick Steinhardt
2025-09-04 0:57 ` brian m. carlson
2025-09-04 11:39 ` Patrick Steinhardt
2025-09-04 13:53 ` Sam James
2025-09-05 3:55 ` Elijah Newren
2025-09-04 23:17 ` Ezekiel Newren
2025-09-05 3:54 ` Elijah Newren
2025-09-05 6:50 ` Patrick Steinhardt
2025-09-07 4:10 ` Elijah Newren
2025-09-07 16:09 ` rsbecker
2025-09-08 10:12 ` Phillip Wood
2025-09-08 15:32 ` rsbecker
2025-09-08 15:10 ` Ezekiel Newren
2025-09-08 15:41 ` rsbecker
2025-09-08 15:31 ` Elijah Newren
2025-09-08 15:36 ` rsbecker
2025-09-08 16:13 ` Elijah Newren
2025-09-08 17:01 ` rsbecker
2025-09-08 6:40 ` Patrick Steinhardt
2025-09-05 10:31 ` Phillip Wood
2025-09-05 11:32 ` Sam James
2025-09-05 13:14 ` Phillip Wood
2025-09-05 13:23 ` Patrick Steinhardt
2025-09-05 15:37 ` Junio C Hamano
2025-09-08 6:40 ` Patrick Steinhardt
2025-08-23 14:29 ` Ezekiel Newren
2025-08-23 3:55 ` [PATCH v3 03/15] github workflows: install rust Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 04/15] win+Meson: do allow linking with the Rust-built xdiff Johannes Schindelin via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 05/15] github workflows: upload Cargo.lock Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 06/15] ivec: create a vector type that is interoperable between C and Rust Ezekiel Newren via GitGitGadget
2025-08-23 8:12 ` Kristoffer Haugsbakk
2025-08-23 9:29 ` Ezekiel Newren
2025-08-23 16:14 ` Junio C Hamano
2025-08-23 16:37 ` Ezekiel Newren
2025-08-23 18:05 ` Junio C Hamano
2025-08-23 20:29 ` Ezekiel Newren
2025-08-25 19:16 ` Elijah Newren
2025-08-26 5:40 ` Junio C Hamano
2025-08-24 13:31 ` Ben Knoble
2025-08-25 20:40 ` Ezekiel Newren
2025-08-26 13:30 ` D. Ben Knoble
2025-08-26 18:47 ` Ezekiel Newren
2025-08-26 22:01 ` brian m. carlson
2025-08-23 3:55 ` [PATCH v3 07/15] xdiff/xprepare: remove superfluous forward declarations Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 08/15] xdiff: delete unnecessary fields from xrecord_t and xdfile_t Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 09/15] xdiff: make fields of xrecord_t Rust friendly Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 10/15] xdiff: use one definition for freeing xdfile_t Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 11/15] xdiff: replace chastore with an ivec in xdfile_t Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 12/15] xdiff: delete nrec field from xdfile_t Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 13/15] xdiff: delete recs " Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 14/15] xdiff: make xdfile_t more rust friendly Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 15/15] xdiff: implement xdl_trim_ends() in Rust Ezekiel Newren via GitGitGadget
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