On Tue, Sep 07 2021, Taylor Blau wrote:
> On Tue, Sep 07, 2021 at 09:42:36PM +0200, Ævar Arnfjörð Bjarmason wrote:
>> Change code added in 5889271114a (finish_tmp_packfile():use strbuf for
>
> s/Change code/Code/ ?
That would make it:
Change code added in X (...) to do strbuf_reset() instead...
Instead of:
Code added in X (...) to do strbuf_reset() instead...
> (I wondered also if the missing space in 5889271114a's subject line was
> intentional, but it does appear in the original commit.)
*Nod*, it was automatically generated.
> Reading this patch, I'm not sure I agree that this makes the later
> changes any easier. To be honest, replacing things like
>
>> if (rev_tmp_name) {
>> - strbuf_addf(name_buffer, "%s.rev", hash_to_hex(hash));
>> - if (rename(rev_tmp_name, name_buffer->buf))
>> + strbuf_addf(&sb, "%s%s.rev", tmp_basename->buf,
>> + hash_to_hex(hash));
>> + if (rename(rev_tmp_name, sb.buf))
>> die_errno("unable to rename temporary reverse-index file");
>> -
>> - strbuf_setlen(name_buffer, basename_len);
>> + strbuf_reset(&sb);
>
> Does not much help or hurt the readability, at least in my opinion. One
> advantage of the pre-image is that we're doing less copying, but that's
> probably splitting hairs at this point.
> So, I would probably be just as happy without this patch. You mentioned
> that it makes the later changes easier, but I couldn't come up with why.
> I may be missing something, in which case it may be helpful to know what
> that is and how it makes this change necessary.
It's not that continually appending/trimming the strbuf is per-se less
readable than having a "prefix" and copying/appending to it, and as you
point out this moves us towards more allocations, but in this case
that's not the bottleneck.
It's that if I retain the current pattern while splitting up these
functions I'd need to pass a "basename_len" owned by the caller between
the two, and we'd end up juggling the "tmpname" as the "if
(write_bitmap_index)" codepath is moved around.
So just having each site get the prefix and add its own suffix seemed
much easier to deal with,.
