Re: [Tarantool-patches] [PATCH v2 4/4] sql: introduce mem_cmp_msgpack()

[Vladislav Shpilevoy via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

Thanks for the fixes!

See 2 comments below.

> diff --git a/src/box/sql.c b/src/box/sql.c
> index 790ca7f70..a5afcfabb 100644
> --- a/src/box/sql.c
> +++ b/src/box/sql.c
> @@ -765,10 +765,12 @@ tarantoolsqlIdxKeyCompare(struct BtCursor *cursor,
>  			}
>  		}
>  		next_fieldno = fieldno + 1;
> -		rc = sqlVdbeCompareMsgpack(&p, unpacked, i);
> +		struct key_part *part = &unpacked->key_def->parts[i];
> +		struct Mem *mem = unpacked->aMem + i;
> +		struct coll *coll = part->coll;
> +		mem_cmp_msgpack(mem, &p, &rc, coll);

1. The same as in the previous patch - you either need to fill
rc out parameter even in case of a fail, or check result of
mem_cmp_msgpack() to keep the results stable. Not depending on
the stack's garbage content.

The same in the other places where it is called.

>  		if (rc != 0) {
> -			if (unpacked->key_def->parts[i].sort_order !=
> -			    SORT_ORDER_ASC)
> +			if (part->sort_order == SORT_ORDER_ASC)
>  				rc = -rc;
>  			goto out;
>  		}
> diff --git a/src/box/sql/mem.c b/src/box/sql/mem.c
> index da27cd191..4062ff4b3 100644
> --- a/src/box/sql/mem.c
> +++ b/src/box/sql/mem.c
> @@ -2077,35 +2077,78 @@ mem_cmp_scalar(const struct Mem *a, const struct Mem *b, int *result,

<...>

> +	case MP_EXT: {
> +		int8_t type;
> +		const char *buf = *b;
> +		uint32_t len = mp_decode_extl(&buf, &type);
> +		if (type == MP_UUID) {
> +			assert(len == UUID_LEN);
> +			mem.type = MEM_TYPE_UUID;
> +			if (mp_decode_uuid(b, &mem.u.uuid) == NULL)
> +				return -1;
> +			break;
> +		}
> +		len += buf - *b;
> +		mem.type = MEM_TYPE_BIN;
> +		mem.z = (char *)*b;
> +		mem.n = len;
> +		mem.flags = MEM_Ephem;
> +		*b += len;
> +		break;

2. I just remembered now, that we have uuid_unpack(). It is better
to use when you already decoded the EXT header. Consider this:

====================
@@ -2129,20 +2129,18 @@ mem_cmp_msgpack(const struct Mem *a, const char **b, int *result,
 	case MP_EXT: {
 		int8_t type;
 		const char *buf = *b;
-		uint32_t len = mp_decode_extl(&buf, &type);
+		uint32_t len = mp_decode_extl(b, &type);
 		if (type == MP_UUID) {
-			assert(len == UUID_LEN);
-			mem.type = MEM_TYPE_UUID;
-			if (mp_decode_uuid(b, &mem.u.uuid) == NULL)
+			if (uuid_unpack(&b, len, &mem.u.uuid) == NULL)
 				return -1;
+			mem.type = MEM_TYPE_UUID;
 			break;
 		}
-		len += buf - *b;
 		mem.type = MEM_TYPE_BIN;
-		mem.z = (char *)*b;
-		mem.n = len;
+		mem.z = (char *)buf;
+		mem.n = b - buf + len;
 		mem.flags = MEM_Ephem;
-		*b += len;
+		b += len;
 		break;
 	}
 	default:
====================

(I didn't test though.)