[tarantool-patches] Re: [PATCH v1 3/4] box: introduce box_space_id_by_name

[Kirill Shcherbatov <kshcherbatov@tarantool.org>]

> 1. The comment now is wrong - space_id_by_name will be used exactly for
> non-public API.
> 2. space_id_by_name must not take system_space_id as an argument. It must
> always use BOX_SPACE_ID.
>   * Return 0 on success, -1 on error.
>   * @param[out] space_id BOX_ID_NIL - not found. Else space_id is
>   *             saved.
> 3. Not _vspace.
> 4. space_id_by_name is not public function. You must not put it inside
> /** \cond public */.
> 5. Why can not you just port schema_find_id to C?
I've ported schema_find_id to C. This required change it's signature.

diff --git a/src/box/schema.cc b/src/box/schema.cc
index 2ddf920..c5055ee 100644
--- a/src/box/schema.cc
+++ b/src/box/schema.cc
@@ -224,28 +224,53 @@ sc_space_new(uint32_t id, const char *name, struct key_def *key_def,
 
 uint32_t
 schema_find_id(uint32_t system_space_id, uint32_t index_id,
-	       const char *name, uint32_t len)
+	       const char *name, uint32_t len, uint32_t *space_id)
 {
-	if (len > BOX_NAME_MAX)
-		return BOX_ID_NIL;
-	struct space *space = space_cache_find_xc(system_space_id);
-	struct index *index = index_find_system_xc(space, index_id);
+	*space_id = BOX_ID_NIL;
+	if (len > BOX_NAME_MAX) {
+		diag_set(SystemError,
+			 "name length %d is greater than BOX_NAME_MAX", len);
+		return -1;
+	}
+	struct space *space = space_cache_find(system_space_id);
+	if (space == NULL)
+		return -1;
+	if (!space_is_memtx(space)) {
+		diag_set(ClientError, ER_UNSUPPORTED,
+			 space->engine->name, "system data");
+		return -1;
+	}
+	struct index *index = index_find(space, index_id);
+	if (index == NULL)
+		return -1;
 	uint32_t size = mp_sizeof_str(len);
 	struct region *region = &fiber()->gc;
 	uint32_t used = region_used(region);
-	char *key = (char *) region_alloc_xc(region, size);
-	auto guard = make_scoped_guard([=] { region_truncate(region, used); });
+	char *key = (char *)region_alloc(region, size);
+	if (key == NULL) {
+		diag_set(OutOfMemory, size, "region", "new slab");
+		return -1;
+	}
 	mp_encode_str(key, name, len);
-
-	struct iterator *it = index_create_iterator_xc(index, ITER_EQ, key, 1);
-	IteratorGuard iter_guard(it);
-
-	struct tuple *tuple = iterator_next_xc(it);
+	struct iterator *it = index_create_iterator(index, ITER_EQ, key, 1);
+	if (it == NULL) {
+		region_truncate(region, used);
+		return -1;
+	}
+	int rc = 0;
+	struct tuple *tuple;
+	if (iterator_next(it, &tuple) != 0) {
+		rc = -1;
+		goto cleanup;
+	}
 	if (tuple) {
 		/* id is always field #1 */
-		return tuple_field_u32_xc(tuple, 0);
+		*space_id = tuple_field_u32_xc(tuple, 0);
 	}
-	return BOX_ID_NIL;
+cleanup:
+	iterator_delete(it);
+	region_truncate(region, used);
+	return rc;
 }
 
 /**
diff --git a/src/box/schema.h b/src/box/schema.h
index 1f7414f..099f9b0 100644
--- a/src/box/schema.h
+++ b/src/box/schema.h
@@ -102,6 +102,22 @@ space_is_system(struct space *space);
 struct sequence *
 sequence_by_id(uint32_t id);
 
+/**
+ * Find space id by name in specified system space with index.
+ *
+ * @param system_space_id identifier of the system space.
+ * @param index_id identifier of the index to lookup.
+ * @param name space to lookup name.
+ * @param len length of a name.
+ * @param space_id[out] space_id BOX_ID_NIL - not found.
+ *
+ * @retval 0 on success.
+ * @retval -1 on error.
+ */
+uint32_t
+schema_find_id(uint32_t system_space_id, uint32_t index_id,
+	       const char *name, uint32_t len, uint32_t *space_id);
+
 #if defined(__cplusplus)
 } /* extern "C" */
 
@@ -134,13 +150,6 @@ schema_free();
 
 struct space *schema_space(uint32_t id);
 
-/*
- * Find object id by object name.
- */
-uint32_t
-schema_find_id(uint32_t system_space_id, uint32_t index_id,
-	       const char *name, uint32_t len);
-
 /**
  * Insert a new function or update the old one.
  *
diff --git a/src/box/user.cc b/src/box/user.cc
index 7fa66da..3e7f466 100644
--- a/src/box/user.cc
+++ b/src/box/user.cc
@@ -450,7 +450,9 @@ user_find(uint32_t uid)
 struct user *
 user_find_by_name(const char *name, uint32_t len)
 {
-	uint32_t uid = schema_find_id(BOX_USER_ID, 2, name, len);
+	uint32_t uid;
+	if (schema_find_id(BOX_USER_ID, 2, name, len, &uid) != 0)
+		diag_raise();
 	struct user *user = user_by_id(uid);
 	if (user == NULL || user->def->type != SC_USER) {
 		diag_set(ClientError, ER_NO_SUCH_USER, tt_cstr(name, len));