On Thu, Aug 21, 2025 at 09:39:10AM +0200, Patrick Steinhardt wrote:
> We have a recurring pattern where we essentially perform an upsert of a
> packfile in case it isn't yet known by the packfile store. The logic to
> do so is non-trivial as we have to reconstruct the packfile's key, check
> the map of packfiles, then create the new packfile and finally add it to
> the store.
>
> Introduce a new function that does this dance for us. Refactor callsites
> to use it.
Nice, I have definitely noticed this pattern before and thought it would
be nice to DRY it up a bit, but never got around to doing so ;-).
> Signed-off-by: Patrick Steinhardt <ps@xxxxxx>
> ---
> builtin/fast-import.c | 4 ++--
> builtin/index-pack.c | 10 +++-------
> midx.c | 18 ++----------------
> packfile.c | 44 +++++++++++++++++++++++++++++++-------------
> packfile.h | 8 ++++++++
> 5 files changed, 46 insertions(+), 38 deletions(-)
>
> diff --git a/builtin/fast-import.c b/builtin/fast-import.c
> index e9d82b31c3..a26e79689d 100644
> --- a/builtin/fast-import.c
> +++ b/builtin/fast-import.c
> @@ -897,11 +897,11 @@ static void end_packfile(void)
> idx_name = keep_pack(create_index());
>
> /* Register the packfile with core git's machinery. */
> - new_p = add_packed_git(pack_data->repo, idx_name, strlen(idx_name), 1);
> + new_p = packfile_store_load_pack(pack_data->repo->objects->packfiles,
> + idx_name, 1);
> if (!new_p)
> die("core git rejected index %s", idx_name);
> all_packs[pack_id] = new_p;
> - packfile_store_add_pack(the_repository->objects->packfiles, new_p);
OK, we can now avoid calling packfile_store_add_pack() explicitly here,
since that is part of the new packfile_store_load_pack() function which
is called a few lines up. That does change the order of operations a
little bit (previously the new pack would end up in 'all_packs' first
before being installed, now it's the other way around), but not in a way
that I think matters.
> diff --git a/builtin/index-pack.c b/builtin/index-pack.c
> index ed490dfad4..2b78ba7fe4 100644
> --- a/builtin/index-pack.c
> +++ b/builtin/index-pack.c
> @@ -1640,13 +1640,9 @@ static void final(const char *final_pack_name, const char *curr_pack_name,
> rename_tmp_packfile(&final_index_name, curr_index_name, &index_name,
> hash, "idx", 1);
>
> - if (do_fsck_object) {
> - struct packed_git *p;
> - p = add_packed_git(the_repository, final_index_name,
> - strlen(final_index_name), 0);
> - if (p)
> - packfile_store_add_pack(the_repository->objects->packfiles, p);
> - }
> + if (do_fsck_object)
> + packfile_store_load_pack(the_repository->objects->packfiles,
> + final_index_name, 0);
Looks obviously correct to me.
> diff --git a/midx.c b/midx.c
> index 3cfe7884ad..d30feda019 100644
> --- a/midx.c
> +++ b/midx.c
> @@ -454,7 +454,6 @@ int prepare_midx_pack(struct repository *r, struct multi_pack_index *m,
> uint32_t pack_int_id)
> {
> struct strbuf pack_name = STRBUF_INIT;
> - struct strbuf key = STRBUF_INIT;
> struct packed_git *p;
>
> pack_int_id = midx_for_pack(&m, pack_int_id);
> @@ -466,22 +465,9 @@ int prepare_midx_pack(struct repository *r, struct multi_pack_index *m,
>
> strbuf_addf(&pack_name, "%s/pack/%s", m->object_dir,
> m->pack_names[pack_int_id]);
> -
> - /* pack_map holds the ".pack" name, but we have the .idx */
> - strbuf_addbuf(&key, &pack_name);
> - strbuf_strip_suffix(&key, ".idx");
> - strbuf_addstr(&key, ".pack");
> - p = hashmap_get_entry_from_hash(&r->objects->packfiles->map,
> - strhash(key.buf), key.buf,
> - struct packed_git, packmap_ent);
> - if (!p) {
> - p = add_packed_git(r, pack_name.buf, pack_name.len, m->local);
> - if (p)
> - packfile_store_add_pack(r->objects->packfiles, p);
> - }
> -
> + p = packfile_store_load_pack(r->objects->packfiles,
> + pack_name.buf, m->local);
Nice. This all looks like it preserves the right behavior, and it's nice
to see the "we have a thing that ends in '.pack', but we need one that
ends in '.idx'" logic get inlined, too.
> diff --git a/packfile.c b/packfile.c
> index a79d0fc1fa..f7a9967c9d 100644
> --- a/packfile.c
> +++ b/packfile.c
> @@ -793,6 +793,33 @@ void packfile_store_add_pack(struct packfile_store *store,
> list_add_tail(&pack->mru, &store->mru);
> }
>
> +struct packed_git *packfile_store_load_pack(struct packfile_store *store,
> + const char *idx_path, int local)
> +{
> + struct strbuf key = STRBUF_INIT;
> + struct packed_git *p;
> +
> + /*
> + * We're being called with the path to the index file, but `pack_map`
> + * holds the path to the packfile itself.
> + */
> + strbuf_addstr(&key, idx_path);
> + strbuf_strip_suffix(&key, ".idx");
> + strbuf_addstr(&key, ".pack");
> +
> + p = hashmap_get_entry_from_hash(&store->map, strhash(key.buf), key.buf,
> + struct packed_git, packmap_ent);
> + if (!p) {
> + p = add_packed_git(store->odb->repo, idx_path,
> + strlen(idx_path), local);
> + if (p)
> + packfile_store_add_pack(store, p);
> + }
> +
> + strbuf_release(&key);
> + return p;
> +}
> +
This all looks good too, and matches the behavior of the callees which
are being refactored.
> void (*report_garbage)(unsigned seen_bits, const char *path);
>
> static void report_helper(const struct string_list *list,
> @@ -892,23 +919,14 @@ static void prepare_pack(const char *full_name, size_t full_name_len,
> const char *file_name, void *_data)
> {
> struct prepare_pack_data *data = (struct prepare_pack_data *)_data;
> - struct packed_git *p;
> size_t base_len = full_name_len;
>
> if (strip_suffix_mem(full_name, &base_len, ".idx") &&
> !(data->m && midx_contains_pack(data->m, file_name))) {
> - struct hashmap_entry hent;
> - char *pack_name = xstrfmt("%.*s.pack", (int)base_len, full_name);
> - unsigned int hash = strhash(pack_name);
> - hashmap_entry_init(&hent, hash);
> -
> - /* Don't reopen a pack we already have. */
> - if (!hashmap_get(&data->r->objects->packfiles->map, &hent, pack_name)) {
> - p = add_packed_git(data->r, full_name, full_name_len, data->local);
> - if (p)
> - packfile_store_add_pack(data->r->objects->packfiles, p);
> - }
> - free(pack_name);
> + char *trimmed_path = xstrndup(full_name, full_name_len);
> + packfile_store_load_pack(data->r->objects->packfiles,
> + trimmed_path, data->local);
I think we could avoid the allocation here by passing along the length
of the string we want to use, as in:
packfile_store_load_pack(data->r->objects->packfiles,
full_name, full_name_len,
data->local);
, but I prefer the way it is written here.
Thanks,
Taylor
