From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Phillip Wood <phillip.wood123@gmail.com>
Cc: git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>,
Jeff King <peff@peff.net>
Subject: Re: [PATCH 5/7] xdiff: use GALLOC_GROW(), not XDL_ALLOC_GROW()
Date: Mon, 11 Jul 2022 12:48:47 +0200 [thread overview]
Message-ID: <220711.861qur9ays.gmgdl@evledraar.gmail.com> (raw)
In-Reply-To: <c2bc5c79-e71b-f9dc-ba97-261d3454e150@gmail.com>
On Mon, Jul 11 2022, Phillip Wood wrote:
> Hi Ævar
>
> On 08/07/2022 15:20, Ævar Arnfjörð Bjarmason wrote:
>> Replace the recently introduced XDL_ALLOC_GROW() with invocations of
>> the GALLOC_GROW() from git-shared-util.h.
>> As this change shows the macro + function indirection of
>> XDL_ALLOC_GROW() is something we needed only because the two callsites
>> we used it in wanted to use it as an expression, and we thus had to
>> pass the "sizeof" down.
>> Let's just check the value afterwards instead, which allows us to
>> use
>> the shared macro, we can also remove xdl_reallo(), this was its last
>> user.
>
> I don't think this expression->statement change is an
> improvement.
I think the use-as-statement is prettier too, but I think the uglyness
of having to pass down the sizeof() & re-implementing the macro version
of the alloc-or-die variant outweights that.
> This change also removes the overflow checks that are
> present in XDL_ALLOC_GROW()[...]
We end up calling st_mult(), which does that overflow check. Do you mean
that the POC shimmy layer I showed in another reply for libgit2 doesn't
have an st_mult() that detects overflows?
That's true, but as noted downthread of that we can & could ship that as
part of the shimmy layer, but that's unrelated to this change.
In your pre-image you use LONG_MAX instead of UINTMAX_MAX & I don't see
(but maybe I haven't looked at it carefully enough) how it does the same
dying on overflows. Doesn't it just fall back to LONG_MAX?
Part of this is that it's not clear to me from your commit(s) why you
need to rewrite alloc_nr() and rewrite (or drop?) st_mult().
> and fails to free the old allocation when
> realloc() fails. It is not a like for like replacement.
Yes, we should have a free() there. Wel spotted. But again, doing that
as part of the "gently" branch seems preferrable to have duplicate
versions for expression (non-fatal) v.s. statement (fatal) variants.
next prev parent reply other threads:[~2022-07-11 11:24 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-29 15:25 [PATCH 0/3] xdiff: introduce memory allocation macros Phillip Wood via GitGitGadget
2022-06-29 15:25 ` [PATCH 1/3] xdiff: introduce XDL_ALLOC_ARRAY() Phillip Wood via GitGitGadget
2022-06-29 15:25 ` [PATCH 2/3] xdiff: introduce XDL_CALLOC_ARRAY() Phillip Wood via GitGitGadget
2022-06-30 18:17 ` Junio C Hamano
2022-07-06 13:17 ` Phillip Wood
2022-06-29 15:25 ` [PATCH 3/3] xdiff: introduce XDL_ALLOC_GROW() Phillip Wood via GitGitGadget
2022-06-30 10:54 ` Ævar Arnfjörð Bjarmason
2022-06-30 12:03 ` Phillip Wood
2022-06-30 12:38 ` Phillip Wood
2022-06-30 13:25 ` Ævar Arnfjörð Bjarmason
2022-07-06 13:23 ` Phillip Wood
2022-07-07 11:17 ` Ævar Arnfjörð Bjarmason
2022-07-08 9:35 ` Phillip Wood
2022-07-08 14:20 ` [PATCH 0/7] xdiff: use standard alloc macros, share them via git-shared-util.h Ævar Arnfjörð Bjarmason
2022-07-08 14:20 ` [PATCH 1/7] xdiff: simplify freeing patterns around xdl_free_env() Ævar Arnfjörð Bjarmason
2022-07-08 14:20 ` [PATCH 2/7] git-shared-util.h: move "shared" allocation utilities here Ævar Arnfjörð Bjarmason
2022-07-08 14:20 ` [PATCH 3/7] git-shared-util.h: add G*() versions of *ALLOC_*() Ævar Arnfjörð Bjarmason
2022-07-11 10:06 ` Phillip Wood
2022-07-08 14:20 ` [PATCH 4/7] xdiff: use G[C]ALLOC_ARRAY(), not XDL_CALLOC_ARRAY() Ævar Arnfjörð Bjarmason
2022-07-11 10:10 ` Phillip Wood
2022-07-08 14:20 ` [PATCH 5/7] xdiff: use GALLOC_GROW(), not XDL_ALLOC_GROW() Ævar Arnfjörð Bjarmason
2022-07-11 10:13 ` Phillip Wood
2022-07-11 10:48 ` Ævar Arnfjörð Bjarmason [this message]
2022-07-13 9:09 ` Phillip Wood
2022-07-13 10:48 ` Ævar Arnfjörð Bjarmason
2022-07-13 13:21 ` Phillip Wood
2022-07-08 14:20 ` [PATCH 6/7] xdiff: remove xdl_malloc() wrapper, use malloc(), not xmalloc() Ævar Arnfjörð Bjarmason
2022-07-08 17:42 ` Phillip Wood
2022-07-08 21:44 ` Ævar Arnfjörð Bjarmason
2022-07-08 19:35 ` Jeff King
2022-07-08 21:47 ` Ævar Arnfjörð Bjarmason
2022-07-11 9:33 ` Jeff King
2022-07-08 14:20 ` [PATCH 7/7] xdiff: remove xdl_free(), use free() instead Ævar Arnfjörð Bjarmason
2022-07-08 17:51 ` Phillip Wood
2022-07-08 21:26 ` Ævar Arnfjörð Bjarmason
2022-07-11 9:26 ` Phillip Wood
2022-07-11 9:54 ` Phillip Wood
2022-07-11 10:02 ` Ævar Arnfjörð Bjarmason
2022-07-13 13:00 ` Phillip Wood
2022-07-13 13:18 ` Ævar Arnfjörð Bjarmason
2022-06-30 18:32 ` [PATCH 3/3] xdiff: introduce XDL_ALLOC_GROW() Junio C Hamano
2022-07-06 13:14 ` Phillip Wood
2022-06-30 10:46 ` [PATCH 0/3] xdiff: introduce memory allocation macros Ævar Arnfjörð Bjarmason
2022-07-08 16:25 ` [PATCH v2 0/4] " Phillip Wood via GitGitGadget
2022-07-08 16:25 ` [PATCH v2 1/4] xdiff: introduce XDL_ALLOC_ARRAY() Phillip Wood via GitGitGadget
2022-07-08 16:25 ` [PATCH v2 2/4] xdiff: introduce xdl_calloc Phillip Wood via GitGitGadget
2022-07-08 16:25 ` [PATCH v2 3/4] xdiff: introduce XDL_CALLOC_ARRAY() Phillip Wood via GitGitGadget
2022-07-08 16:25 ` [PATCH v2 4/4] xdiff: introduce XDL_ALLOC_GROW() Phillip Wood via GitGitGadget
2022-07-08 22:17 ` Ævar Arnfjörð Bjarmason
2022-07-11 10:00 ` Phillip Wood
2022-07-12 7:19 ` Jeff King
2022-07-13 9:38 ` Phillip Wood
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: http://vger.kernel.org/majordomo-info.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=220711.861qur9ays.gmgdl@evledraar.gmail.com \
--to=avarab@gmail.com \
--cc=git@vger.kernel.org \
--cc=gitster@pobox.com \
--cc=peff@peff.net \
--cc=phillip.wood123@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://80x24.org/mirrors/git.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).