@leroysheep / LeeRoySheep / commits / ae61324f0a

pack-bitmap.c: teach `bitmap_for_commit()` about incremental MIDXs

The pack-bitmap machinery uses `bitmap_for_commit()` to locate the EWAH-compressed bitmap corresponding to some given commit object. Teach this function about incremental MIDX bitmaps by teaching it to recur on earlier bitmap layers when it fails to find a given commit in the current layer. The changes to do so are as follows: - Avoid initializing hash_pos at its declaration, since bitmap_for_commit() is now a recursive function and may receive a NULL bitmap_index pointer as its first argument. - In cases where we would previously return NULL (to indicate that a lookup failed and the given bitmap_index does not contain an entry corresponding to the given commit), recursively call the function on the previous bitmap layer. Signed-off-by: Taylor Blau <me@ttaylorr.com> Acked-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Taylor Blau committed Mar 20, 2025 at 13:56 UTC ae61324f0a6124534a245b70d55d63b5abf3e5d4

1 file changed +7 -4

pack-bitmap.c

+7 -4

index e84211de15..17f1087fba 100644 --- a/pack-bitmap.c +++ b/pack-bitmap.c @@ -941,18 +941,21 @@ corrupt: struct ewah_bitmap *bitmap_for_commit(struct bitmap_index *bitmap_git, struct commit *commit) { - khiter_t hash_pos = kh_get_oid_map(bitmap_git->bitmaps, - commit->object.oid); + khiter_t hash_pos; + if (!bitmap_git) + return NULL; + + hash_pos = kh_get_oid_map(bitmap_git->bitmaps, commit->object.oid); if (hash_pos >= kh_end(bitmap_git->bitmaps)) { struct stored_bitmap *bitmap = NULL; if (!bitmap_git->table_lookup) - return NULL; + return bitmap_for_commit(bitmap_git->base, commit); /* this is a fairly hot codepath - no trace2_region please */ /* NEEDSWORK: cache misses aren't recorded */ bitmap = lazy_bitmap_for_commit(bitmap_git, commit); if (!bitmap) - return NULL; + return bitmap_for_commit(bitmap_git->base, commit); return lookup_stored_bitmap(bitmap); } return lookup_stored_bitmap(kh_value(bitmap_git->bitmaps, hash_pos));