[PATCH v3 2/4] box: refactor key_validate_parts to return key_end

[Kirill Shcherbatov <kshcherbatov@tarantool.org>]

The key_validate_parts helper is refactored to return a pointer
to the end of a given key argument in case of success.
This is required to effectively validate a sequence of keys in
scope of functional multikey indexes.

Needed for #1260
---
 src/box/index.cc      | 6 ++++--
 src/box/key_def.c     | 4 +++-
 src/box/key_def.h     | 4 +++-
 src/box/lua/key_def.c | 5 +++--
 src/box/vinyl.c       | 4 +++-
 5 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/src/box/index.cc b/src/box/index.cc
index 7f26c9bc2..843d0e73d 100644
--- a/src/box/index.cc
+++ b/src/box/index.cc
@@ -126,8 +126,9 @@ key_validate(const struct index_def *index_def, enum iterator_type type,
 				 part_count);
 			return -1;
 		}
+		const char *key_end;
 		if (key_validate_parts(index_def->key_def, key,
-				       part_count, true) != 0)
+				       part_count, true, &key_end) != 0)
 			return -1;
 	}
 	return 0;
@@ -143,7 +144,8 @@ exact_key_validate(struct key_def *key_def, const char *key,
 			 part_count);
 		return -1;
 	}
-	return key_validate_parts(key_def, key, part_count, false);
+	const char *key_end;
+	return key_validate_parts(key_def, key, part_count, false, &key_end);
 }
 
 char *
diff --git a/src/box/key_def.c b/src/box/key_def.c
index 2aa095091..ee758eefa 100644
--- a/src/box/key_def.c
+++ b/src/box/key_def.c
@@ -834,7 +834,8 @@ out:
 
 int
 key_validate_parts(const struct key_def *key_def, const char *key,
-		   uint32_t part_count, bool allow_nullable)
+		   uint32_t part_count, bool allow_nullable,
+		   const char **key_end)
 {
 	for (uint32_t i = 0; i < part_count; i++) {
 		const struct key_part *part = &key_def->parts[i];
@@ -844,5 +845,6 @@ key_validate_parts(const struct key_def *key_def, const char *key,
 			return -1;
 		mp_next(&key);
 	}
+	*key_end = key;
 	return 0;
 }
diff --git a/src/box/key_def.h b/src/box/key_def.h
index ab4b7c087..df83d055c 100644
--- a/src/box/key_def.h
+++ b/src/box/key_def.h
@@ -443,13 +443,15 @@ key_def_find_pk_in_cmp_def(const struct key_def *cmp_def,
  * @param key MessagePack'ed data for matching.
  * @param part_count Field count in the key.
  * @param allow_nullable True if nullable parts are allowed.
+ * @param key_end[out] The end of the validated key.
  *
  * @retval 0  The key is valid.
  * @retval -1 The key is invalid.
  */
 int
 key_validate_parts(const struct key_def *key_def, const char *key,
-		   uint32_t part_count, bool allow_nullable);
+		   uint32_t part_count, bool allow_nullable,
+		   const char **key_end);
 
 /**
  * Return true if @a index_def defines a sequential key without
diff --git a/src/box/lua/key_def.c b/src/box/lua/key_def.c
index 052a1c85d..041b5ec98 100644
--- a/src/box/lua/key_def.c
+++ b/src/box/lua/key_def.c
@@ -338,9 +338,10 @@ lbox_key_def_compare_with_key(struct lua_State *L)
 	struct region *region = &fiber()->gc;
 	size_t region_svp = region_used(region);
 	size_t key_len;
-	const char *key = lbox_encode_tuple_on_gc(L, 3, &key_len);
+	const char *key_end, *key = lbox_encode_tuple_on_gc(L, 3, &key_len);
 	uint32_t part_count = mp_decode_array(&key);
-	if (key_validate_parts(key_def, key, part_count, true) != 0) {
+	if (key_validate_parts(key_def, key, part_count, true,
+			       &key_end) != 0) {
 		region_truncate(region, region_svp);
 		tuple_unref(tuple);
 		return luaT_error(L);
diff --git a/src/box/vinyl.c b/src/box/vinyl.c
index f68958ba1..cf7af26b7 100644
--- a/src/box/vinyl.c
+++ b/src/box/vinyl.c
@@ -1751,7 +1751,9 @@ vy_unique_key_validate(struct vy_lsm *lsm, const char *key,
 			 original_part_count, part_count);
 		return -1;
 	}
-	return key_validate_parts(lsm->cmp_def, key, part_count, false);
+	const char *key_end;
+	return key_validate_parts(lsm->cmp_def, key, part_count, false,
+				  &key_end);
 }
 
 /**
-- 
2.22.0