(* hey emacs, this is OCaml code: -*- tuareg -*- *)
(* libnbd OCaml test case
 * Copyright Red Hat
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *)

(* Note: Uses the old NBD.Buffer.t from libnbd <= 1.18 *)

open Ocaml_test_config

open Printf

(* These can be any two unique errors.  They are just used as a sentinel. *)
let test_error1 = Unix.ENETDOWN
let test_error2 = Unix.ENETUNREACH

let expected =
  let b = Bytes.create 512 in
  for i = 0 to 512/8-1 do
    let i64 = Int64.of_int (i*8) in
    bytes_set_int64_be b (i*8) i64
  done;
  b

let chunk user_data buf2 offset s err =
  assert (!err = 0);
  err := NBD.errno_of_unix_error test_error1;
  if user_data <> 42 then invalid_arg "this should be turned into NBD.Error";
  assert (buf2 = expected);
  assert (offset = 0_L);
  assert (s = Int32.to_int NBD.read_data);
  0

let callback user_data err =
  if fst user_data = 42 then
    assert (!err = 0)
  else
    assert (!err = NBD.errno_of_unix_error test_error1);
  err := NBD.errno_of_unix_error test_error2;
  if snd user_data <> 42 then
    invalid_arg "this should be turned into NBD.Error";
  0

let () =
  let nbd = NBD.create () in
  NBD.connect_command nbd [nbdkit; "-s"; "--exit-with-parent"; "-v";
                           "pattern"; "size=512"];

  (* First try: succeed in both callbacks *)
  let buf = NBD.Buffer.alloc 512 in
  let cookie = NBD.aio_pread_structured nbd buf 0_L (chunk 42)
                 ~completion:(callback (42, 42)) in
  while not (NBD.aio_command_completed nbd cookie) do
    ignore (NBD.poll nbd (-1))
  done;

  let buf = NBD.Buffer.to_bytes buf in

  assert (buf = expected);

  (* Second try: fail only during callback *)
  let buf = NBD.Buffer.alloc 512 in
  let cookie = NBD.aio_pread_structured nbd buf 0_L (chunk 42)
                 ~completion:(callback (42, 43)) in
  (try
     while not (NBD.aio_command_completed nbd cookie) do
       ignore (NBD.poll nbd (-1))
     done;
     assert false
   with
   | NBD.Error (_, Some errno) when errno = test_error2 -> ()
   | NBD.Error (_, _) -> assert false
  );

  (* Third try: fail during both *)
  let buf = NBD.Buffer.alloc 512 in
  let cookie = NBD.aio_pread_structured nbd buf 0_L (chunk 44)
                 ~completion:(callback (43, 43)) in
  (try
     while not (NBD.aio_command_completed nbd cookie) do
       ignore (NBD.poll nbd (-1))
     done;
     assert false
   with
   | NBD.Error (_, Some errno) when errno = test_error2 -> ()
   | NBD.Error (_, _) -> assert false
  );

  (* Fourth try: fail only during chunk *)
  let buf = NBD.Buffer.alloc 512 in
  let cookie = NBD.aio_pread_structured nbd buf 0_L (chunk 43)
                 ~completion:(callback (43, 42)) in
  (try
     while not (NBD.aio_command_completed nbd cookie) do
       ignore (NBD.poll nbd (-1))
     done;
     assert false
   with
   | NBD.Error (_, Some errno) when errno = test_error1 -> ()
   | NBD.Error (_, _) -> assert false
  )

let () = Gc.compact ()
