@matheusbsbs / matheus-bagliano / 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

@@ -941,18 +941,21 @@ corrupt:

941 struct ewah_bitmap *bitmap_for_commit(struct bitmap_index *bitmap_git,

942 struct commit *commit)

943 {

944 - khiter_t hash_pos = kh_get_oid_map(bitmap_git->bitmaps,

945 - commit->object.oid);

944 + khiter_t hash_pos;

945 + if (!bitmap_git)

946 + return NULL;

947 +

948 + hash_pos = kh_get_oid_map(bitmap_git->bitmaps, commit->object.oid);

949 if (hash_pos >= kh_end(bitmap_git->bitmaps)) {

950 struct stored_bitmap *bitmap = NULL;

951 if (!bitmap_git->table_lookup)

949 - return NULL;

952 + return bitmap_for_commit(bitmap_git->base, commit);

953

954 /* this is a fairly hot codepath - no trace2_region please */

955 /* NEEDSWORK: cache misses aren't recorded */

956 bitmap = lazy_bitmap_for_commit(bitmap_git, commit);

957 if (!bitmap)

955 - return NULL;

958 + return bitmap_for_commit(bitmap_git->base, commit);

959 return lookup_stored_bitmap(bitmap);

960 }

961 return lookup_stored_bitmap(kh_value(bitmap_git->bitmaps, hash_pos));