object-name: move logic to iterate through packed prefixed objects

Similar to the preceding commit, move the logic to iterate through
objects that have a given prefix into "packfile.c".

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 174 insertions, 0 deletions

diff --git a/packfile.c b/packfile.c
index a6f3d2035d..2539a371c1 100644
--- a/packfile.c
+++ b/packfile.c
@@ -2371,6 +2371,177 @@ static int packfile_store_for_each_object_wrapper(const struct object_id *oid,
 	}
 }
 
+static int match_hash(unsigned len, const unsigned char *a, const unsigned char *b)
+{
+	do {
+		if (*a != *b)
+			return 0;
+		a++;
+		b++;
+		len -= 2;
+	} while (len > 1);
+	if (len)
+		if ((*a ^ *b) & 0xf0)
+			return 0;
+	return 1;
+}
+
+static int for_each_prefixed_object_in_midx(
+	struct packfile_store *store,
+	struct multi_pack_index *m,
+	const struct odb_for_each_object_options *opts,
+	struct packfile_store_for_each_object_wrapper_data *data)
+{
+	int ret;
+
+	for (; m; m = m->base_midx) {
+		uint32_t num, i, first = 0;
+		int len = opts->prefix_hex_len > m->source->odb->repo->hash_algo->hexsz ?
+			m->source->odb->repo->hash_algo->hexsz : opts->prefix_hex_len;
+
+		if (!m->num_objects)
+			continue;
+
+		num = m->num_objects + m->num_objects_in_base;
+
+		bsearch_one_midx(opts->prefix, m, &first);
+
+		/*
+		 * At this point, "first" is the location of the lowest
+		 * object with an object name that could match "opts->prefix".
+		 * See if we have 0, 1 or more objects that actually match(es).
+		 */
+		for (i = first; i < num; i++) {
+			const struct object_id *current = NULL;
+			struct object_id oid;
+
+			current = nth_midxed_object_oid(&oid, m, i);
+
+			if (!match_hash(len, opts->prefix->hash, current->hash))
+				break;
+
+			if (data->request) {
+				struct object_info oi = *data->request;
+
+				ret = packfile_store_read_object_info(store, current,
+								      &oi, 0);
+				if (ret)
+					goto out;
+
+				ret = data->cb(&oid, &oi, data->cb_data);
+				if (ret)
+					goto out;
+			} else {
+				ret = data->cb(&oid, NULL, data->cb_data);
+				if (ret)
+					goto out;
+			}
+		}
+	}
+
+	ret = 0;
+
+out:
+	return ret;
+}
+
+static int for_each_prefixed_object_in_pack(
+	struct packfile_store *store,
+	struct packed_git *p,
+	const struct odb_for_each_object_options *opts,
+	struct packfile_store_for_each_object_wrapper_data *data)
+{
+	uint32_t num, i, first = 0;
+	int len = opts->prefix_hex_len > p->repo->hash_algo->hexsz ?
+		p->repo->hash_algo->hexsz : opts->prefix_hex_len;
+	int ret;
+
+	num = p->num_objects;
+	bsearch_pack(opts->prefix, p, &first);
+
+	/*
+	 * At this point, "first" is the location of the lowest object
+	 * with an object name that could match "bin_pfx".  See if we have
+	 * 0, 1 or more objects that actually match(es).
+	 */
+	for (i = first; i < num; i++) {
+		struct object_id oid;
+
+		nth_packed_object_id(&oid, p, i);
+		if (!match_hash(len, opts->prefix->hash, oid.hash))
+			break;
+
+		if (data->request) {
+			struct object_info oi = *data->request;
+
+			ret = packfile_store_read_object_info(store, &oid, &oi, 0);
+			if (ret)
+				goto out;
+
+			ret = data->cb(&oid, &oi, data->cb_data);
+			if (ret)
+				goto out;
+		} else {
+			ret = data->cb(&oid, NULL, data->cb_data);
+			if (ret)
+				goto out;
+		}
+	}
+
+	ret = 0;
+
+out:
+	return ret;
+}
+
+static int packfile_store_for_each_prefixed_object(
+	struct packfile_store *store,
+	const struct odb_for_each_object_options *opts,
+	struct packfile_store_for_each_object_wrapper_data *data)
+{
+	struct packfile_list_entry *e;
+	struct multi_pack_index *m;
+	bool pack_errors = false;
+	int ret;
+
+	if (opts->flags)
+		BUG("flags unsupported");
+
+	store->skip_mru_updates = true;
+
+	m = get_multi_pack_index(store->source);
+	if (m) {
+		ret = for_each_prefixed_object_in_midx(store, m, opts, data);
+		if (ret)
+			goto out;
+	}
+
+	for (e = packfile_store_get_packs(store); e; e = e->next) {
+		if (e->pack->multi_pack_index)
+			continue;
+
+		if (open_pack_index(e->pack)) {
+			pack_errors = true;
+			continue;
+		}
+
+		if (!e->pack->num_objects)
+			continue;
+
+		ret = for_each_prefixed_object_in_pack(store, e->pack, opts, data);
+		if (ret)
+			goto out;
+	}
+
+	ret = 0;
+
+out:
+	store->skip_mru_updates = false;
+	if (!ret && pack_errors)
+		ret = -1;
+	return ret;
+}
+
 int packfile_store_for_each_object(struct packfile_store *store,
 				   const struct object_info *request,
 				   odb_for_each_object_cb cb,
@@ -2386,6 +2557,9 @@ int packfile_store_for_each_object(struct packfile_store *store,
 	struct packfile_list_entry *e;
 	int pack_errors = 0, ret;
 
+	if (opts->prefix)
+		return packfile_store_for_each_prefixed_object(store, opts, &data);
+
 	store->skip_mru_updates = true;
 
 	for (e = packfile_store_get_packs(store); e; e = e->next) {