Re: [tarantool-patches] [PATCH v3 4/7] iproto: replace obuf by mpstream in execute.c

[Vladimir Davydov <vdavydov.dev@gmail.com>]

On Tue, Nov 27, 2018 at 10:25:43PM +0300, imeevma@tarantool.org wrote:
> @@ -627,81 +610,53 @@ sql_prepare_and_execute(const struct sql_request *request,
>  }
>  
>  int
> -sql_response_dump(struct sql_response *response, int *keys, struct obuf *out)
> +sql_response_dump(struct sql_response *response, int *keys,
> +		  struct mpstream *stream)
>  {
>  	sqlite3 *db = sql_get();
>  	struct sqlite3_stmt *stmt = (struct sqlite3_stmt *) response->prep_stmt;
> -	struct port_tuple *port_tuple = (struct port_tuple *) &response->port;
>  	int rc = 0, column_count = sqlite3_column_count(stmt);
>  	if (column_count > 0) {
> -		if (sql_get_description(stmt, out, column_count) != 0) {
> +		if (sql_get_description(stmt, stream, column_count) != 0) {
>  err:
>  			rc = -1;
>  			goto finish;
>  		}
>  		*keys = 2;
> -		int size = mp_sizeof_uint(IPROTO_DATA) +
> -			   mp_sizeof_array(port_tuple->size);
> -		char *pos = (char *) obuf_alloc(out, size);
> -		if (pos == NULL) {
> -			diag_set(OutOfMemory, size, "obuf_alloc", "pos");
> -			goto err;
> -		}
> -		pos = mp_encode_uint(pos, IPROTO_DATA);
> -		pos = mp_encode_array(pos, port_tuple->size);
> -		/*
> -		 * Just like SELECT, SQL uses output format compatible
> -		 * with Tarantool 1.6
> -		 */
> -		if (port_dump_msgpack_16(&response->port, out) < 0) {
> +		mpstream_encode_uint(stream, IPROTO_DATA);
> +		mpstream_flush(stream);
> +		if (port_dump_msgpack(&response->port, stream->ctx) < 0) {

stream->ctx isn't guaranteed to be an obuf

And when you introduce vstream later, you simply move this code to
another file. This is confusing. May be we should pass alloc/reserve
used in mpstream to port_dump instead of obuf?