On Fri, Jan 08, 2021 at 01:18:06PM -0500, Taylor Blau wrote:
> To prepare for on-disk reverse indexes, remove a spot in
> 'offset_to_pack_pos()' that looks at the 'revindex' array in 'struct
> packed_git'.
>
> Even though this use of the revindex pointer is within pack-revindex.c,
> this clean up is still worth doing. Since the 'revindex' pointer will be
> NULL when reading from an on-disk reverse index (instead the
> 'revindex_data' pointer will be mmaped to the 'pack-*.rev' file), this
> call-site would have to include a conditional to lookup the offset for
> position 'mi' each iteration through the search.
>
> So instead of open-coding 'pack_pos_to_offset()', call it directly from
> within 'offset_to_pack_pos()'.
This definitely makes sense in the long run. I could take or leave it as
a final patch in _this_ series (as opposed to the first patch in a
subsequent series adding the rev files).
> do {
> const unsigned mi = lo + (hi - lo) / 2;
> - if (revindex[mi].offset == ofs) {
> + off_t got = pack_pos_to_offset(p, mi);
They're both constant-time, so performance should be the same big-O. The
function has extra BUG() checks. I doubt those are measurable in
practice, though.
-Peff
