From: Junio C Hamano <gitster@pobox.com>
To: "René Scharfe" <l.s.r@web.de>
Cc: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"Git List" <git@vger.kernel.org>,
"Victoria Dye" <vdye@github.com>
Subject: Re: [PATCH] cache-tree: fix strbuf growth in prime_cache_tree_rec()
Date: Fri, 10 Feb 2023 12:33:00 -0800 [thread overview]
Message-ID: <xmqqwn4pgt1f.fsf@gitster.g> (raw)
In-Reply-To: <850c94d5-973a-335e-903f-e0ab7e52f37e@web.de> ("René Scharfe"'s message of "Fri, 10 Feb 2023 21:20:19 +0100")
René Scharfe <l.s.r@web.de> writes:
>>> - strbuf_grow(tree_path, base_path_len + entry.pathlen + 1);
>>> + strbuf_grow(tree_path, entry.pathlen + 1);
>>> strbuf_add(tree_path, entry.path, entry.pathlen);
>>> strbuf_addch(tree_path, '/');
>>> }
>>
>> The size_t conversion is trivially correct.
>>
>> But what do you mean with "don't double the[...]"? Do you mean that this
>> manages to evade growing these to 24 etc?
>
> strbuf_setlen() truncates the string to the directory name. strbuf_grow() then
> makes enough room to add that directory name again (that's what I mean with
> "double") plus the entry path. We don't add the directory name a second time,
> so we don't need to make room for it.
Yeah, I think I made the same mistake number of years ago, thinking
that strbuf_grow() was to grow the buffer to the given size, but in
reality it is to grow the buffer by the given size, which felt a bit
unnatural, at least to me. I do not feel it too strongly but we
might want to rename _grow() to _grow_by() and make _grow() call it
while giving deprecation warning X-<.
There are ~45 calls to strbuf_grow() in C files other than strbuf.c;
I suspect probably a half or more of them can and should be removed
to reduce the resulting code size without hurting anything.
next prev parent reply other threads:[~2023-02-10 20:33 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-04 19:10 [PATCH] cache-tree: fix strbuf growth in prime_cache_tree_rec() René Scharfe
2023-02-05 21:12 ` Ævar Arnfjörð Bjarmason
2023-02-06 15:27 ` Derrick Stolee
2023-02-06 16:18 ` Ævar Arnfjörð Bjarmason
2023-02-12 11:20 ` René Scharfe
2023-02-06 18:55 ` Junio C Hamano
2023-02-10 20:20 ` René Scharfe
2023-02-10 20:20 ` René Scharfe
2023-02-10 20:33 ` Junio C Hamano [this message]
2023-02-11 2:15 ` Jeff King
2023-02-11 2:46 ` Junio C Hamano
2023-02-10 20:20 ` [PATCH v2] " René Scharfe
2023-02-13 13:37 ` Derrick Stolee
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