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@xxxxxxxxxxxx>
---
midx-write.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/midx-write.c b/midx-write.c
index a77ee73c68..0accbdbb04 100644
--- a/midx-write.c
+++ b/midx-write.c
@@ -196,7 +196,7 @@ static int nth_midxed_pack_midx_entry(struct multi_pack_index *m,
struct pack_midx_entry *e,
uint32_t pos)
{
- if (pos >= m->num_objects)
+ if (pos >= m->num_objects + m->num_objects_in_base)
return 1;
nth_midxed_object_oid(&e->oid, m, pos);
@@ -247,12 +247,16 @@ static void midx_fanout_add_midx_fanout(struct midx_fanout *fanout,
uint32_t cur_fanout,
int preferred_pack)
{
- uint32_t start = 0, end;
+ uint32_t start = m->num_objects_in_base, end;
uint32_t cur_object;
+ if (m->base_midx)
+ midx_fanout_add_midx_fanout(fanout, m->base_midx, cur_fanout,
+ preferred_pack);
+
if (cur_fanout)
- start = ntohl(m->chunk_oid_fanout[cur_fanout - 1]);
- end = ntohl(m->chunk_oid_fanout[cur_fanout]);
+ start += ntohl(m->chunk_oid_fanout[cur_fanout - 1]);
+ end = m->num_objects_in_base + ntohl(m->chunk_oid_fanout[cur_fanout]);
for (cur_object = start; cur_object < end; cur_object++) {
if ((preferred_pack > -1) &&
--
2.46.0.46.g406f326d27.dirty
