@matheusbsbs / matheus-bagliano / commits / 97fd770ea1

midx: teach `midx_fanout_add_midx_fanout()` about incremental MIDXs

The function `midx_fanout_add_midx_fanout()` is used to help construct the fanout table when generating a MIDX by reusing data from an existing MIDX. Prepare this function to work with incremental MIDXs by making a few changes: - The bounds checks need to be adjusted to start object lookups taking into account the number of objects in the previous MIDX layer (i.e., by starting the lookups at position `m->num_objects_in_base` instead of position 0). - Likewise, the bounds checks need to end at `m->num_objects_in_base` objects after `m->num_objects`. - Finally, `midx_fanout_add_midx_fanout()` needs to recur on earlier MIDX layers when dealing with an incremental MIDX chain by calling itself when given a MIDX with a non-NULL `base_midx`. Note that after 0c5a62f14b (midx-write.c: do not read existing MIDX with `packs_to_include`, 2024-06-11), we do not use this function with an existing MIDX (incremental or not) when generating a MIDX with --stdin-packs, and likewise for incremental MIDXs. But it is still used when adding the fanout table from an incremental MIDX when generating a non-incremental MIDX (without --stdin-packs, of course). Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Taylor Blau committed Aug 6, 2024 at 11:37 UTC 97fd770ea1d2ccf9581c4962a1238d853540ec11

1 file changed +8 -4

midx-write.c

+8 -4

@@ -196,7 +196,7 @@ static int nth_midxed_pack_midx_entry(struct multi_pack_index *m,

196 struct pack_midx_entry *e,

197 uint32_t pos)

198 {

199 - if (pos >= m->num_objects)

199 + if (pos >= m->num_objects + m->num_objects_in_base)

200 return 1;

201

202 nth_midxed_object_oid(&e->oid, m, pos);

@@ -247,12 +247,16 @@ static void midx_fanout_add_midx_fanout(struct midx_fanout *fanout,

247 uint32_t cur_fanout,

248 int preferred_pack)

249 {

250 - uint32_t start = 0, end;

250 + uint32_t start = m->num_objects_in_base, end;

251 uint32_t cur_object;

252

253 + if (m->base_midx)

254 + midx_fanout_add_midx_fanout(fanout, m->base_midx, cur_fanout,

255 + preferred_pack);

256 +

257 if (cur_fanout)

254 - start = ntohl(m->chunk_oid_fanout[cur_fanout - 1]);

255 - end = ntohl(m->chunk_oid_fanout[cur_fanout]);

258 + start += ntohl(m->chunk_oid_fanout[cur_fanout - 1]);

259 + end = m->num_objects_in_base + ntohl(m->chunk_oid_fanout[cur_fanout]);

260

261 for (cur_object = start; cur_object < end; cur_object++) {

262 if ((preferred_pack > -1) &&