midx: implement `midx_locate_pack()`

The multi-pack index API exposes a `midx_contains_pack()` function that takes in a string ending in either ".idx" or ".pack" and returns whether or not the MIDX contains a given pack corresponding to that string. There is no corresponding function to locate the position of a pack within the MIDX's pack order (sorted lexically by pack filename). We could add an optional out parameter to `midx_contains_pack()` that is filled out with the pack's position when the parameter is non-NULL. To minimize the amount of fallout from this change, instead introduce a new function by renaming `midx_contains_pack()` to `midx_locate_pack()`, adding that output parameter, and then reimplementing `midx_contains_pack()` in terms of it. Future patches will make use of this new function. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Taylor Blau committed Dec 14, 2023 at 17:23 UTC 307d75bbe6b33267872633173a5d9b5d88b87793
2 files changed +15 -3
midx.c
+11 -2
index de25612b0c..beaf0c0de4 100644 --- a/midx.c +++ b/midx.c @@ -428,7 +428,8 @@ static int cmp_idx_or_pack_name(const char *idx_or_pack_name, return strcmp(idx_or_pack_name, idx_name); } -int midx_contains_pack(struct multi_pack_index *m, const char *idx_or_pack_name) +int midx_locate_pack(struct multi_pack_index *m, const char *idx_or_pack_name, + uint32_t *pos) { uint32_t first = 0, last = m->num_packs; @@ -439,8 +440,11 @@ int midx_contains_pack(struct multi_pack_index *m, const char *idx_or_pack_name) current = m->pack_names[mid]; cmp = cmp_idx_or_pack_name(idx_or_pack_name, current); - if (!cmp) + if (!cmp) { + if (pos) + *pos = mid; return 1; + } if (cmp > 0) { first = mid + 1; continue; @@ -451,6 +455,11 @@ int midx_contains_pack(struct multi_pack_index *m, const char *idx_or_pack_name) return 0; } +int midx_contains_pack(struct multi_pack_index *m, const char *idx_or_pack_name) +{ + return midx_locate_pack(m, idx_or_pack_name, NULL); +} + int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, int local) { struct multi_pack_index *m;
midx.h
+4 -1
index b404235db5..89c5aa637e 100644 --- a/midx.h +++ b/midx.h @@ -70,7 +70,10 @@ struct object_id *nth_midxed_object_oid(struct object_id *oid, struct multi_pack_index *m, uint32_t n); int fill_midx_entry(struct repository *r, const struct object_id *oid, struct pack_entry *e, struct multi_pack_index *m); -int midx_contains_pack(struct multi_pack_index *m, const char *idx_or_pack_name); +int midx_contains_pack(struct multi_pack_index *m, + const char *idx_or_pack_name); +int midx_locate_pack(struct multi_pack_index *m, const char *idx_or_pack_name, + uint32_t *pos); int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, int local); /*