[Tarantool-patches] [PATCH 11/20] net.box: rewrite response decoder in C

[Cyrill Gorcunov]

On Fri, Jul 23, 2021 at 02:07:21PM +0300, Vladimir Davydov via Tarantool-patches wrote:
> This patch moves method_decoder table from Lua to C. This is a step
> towards rewriting performance-critical parts of net.box in C.
...
> +static int
> +netbox_decode_method(struct lua_State *L)
> +{
> +	typedef void (*method_decoder_f)(struct lua_State *L, const char **data,
> +					 const char *data_end,
> +					 struct tuple_format *format);
> +	static method_decoder_f method_decoder[] = {
> +		[NETBOX_PING]		= netbox_decode_nil,
> +		[NETBOX_CALL_16]	= netbox_decode_select,
...
> +		[NETBOX_INJECT]		= netbox_decode_table,
> +	};
> +	enum netbox_method method = lua_tointeger(L, 1);
> +	assert(method < netbox_method_MAX);

Should not it be runtime testing like

	if (method < 0 || method >= lengthof(method_decoder) ||
	    method_decoder[method] == NULL) {
		// Some Lua error thrown
		return luaT_error();
	}

or we've validated this data somewhere already?