fs.open using macros

gistfile1.txt

#define SETUP_REQ \
  uv_fs_cb cb = NULL;                                             \
  uv_loop_t *loop = luv_get_loop(L);                              \
  fs_req_holder *holder = (fs_req_holder *)create_obj_init_ref(L, \
      sizeof(fs_req_holder), "lev.fs");                           \
  /* NOTE: set_call needs "object" to be stack at index 1 */      \
  lua_insert(L, 1);                                               \
  uv_fs_t *req = &holder->req;

#define SET_OPT_CB(index, c_callback) \
  if (lua_isfunction(L, (index))) {                               \
    set_callback(L, CALLBACK_NAME, (index));                      \
    lev_handle_ref(L, (LevRefStruct_t *)holder, -1);              \
    cb = (c_callback);                                            \
  }

#define POST_OPERATION \
  /* NOTE: remove "object" */                                     \
  lua_remove(L, 1);                                               \
  if (req->result == -1) {                                        \
    lev_push_uv_err(L, LEV_UV_ERR_FROM_REQ(req));                 \
    return 1;                                                     \
  }                                                               \
  if (cb) {                                                       \
    return 0;                                                     \
  } else {                                                        \
    int ret_n = push_results(L, req);                             \
    uv_fs_req_cleanup(req);                                       \
    return ret_n;                                                 \
  }


/*
 * fs.open
 */
static int fs_open(lua_State* L) {
  SETUP_REQ;

  /* NOTE: index is added by 1 because of holder above. */
  const char *path = luaL_checkstring(L, 2);
  int flags = fs_checkflags(L, 3);
  int mode = luaL_optint(L, 4, 0666);
  SET_OPT_CB(5, on_fs_callback);

  uv_fs_open(loop, req, path, flags, mode, cb);

  POST_OPERATION;
}