union Any {
  Accept,
  Cache,
  Chdir,
  Chmod,
  Chown,
  Close,
  CopyFile,
  CreateWorker,
  CreateWorkerRes,
  Cwd,
  CwdRes,
  Dial,
  Environ,
  EnvironRes,
  Exit,
  Fetch,
  FetchModuleMetaData,
  FetchModuleMetaDataRes,
  FetchRes,
  FormatError,
  FormatErrorRes,
  GetRandomValues,
  GlobalTimer,
  GlobalTimerRes,
  GlobalTimerStop,
  HostGetMessage,
  HostGetMessageRes,
  HostGetWorkerClosed,
  HostPostMessage,
  IsTTY,
  IsTTYRes,
  Kill,
  Link,
  Listen,
  ListenRes,
  MakeTempDir,
  MakeTempDirRes,
  Metrics,
  MetricsRes,
  Mkdir,
  NewConn,
  Now,
  NowRes,
  Open,
  OpenRes,
  PermissionRevoke,
  Permissions,
  PermissionsRes,
  Read,
  ReadDir,
  ReadDirRes,
  ReadRes,
  Readlink,
  ReadlinkRes,
  Remove,
  Rename,
  ReplReadline,
  ReplReadlineRes,
  ReplStart,
  ReplStartRes,
  Resources,
  ResourcesRes,
  Run,
  RunRes,
  RunStatus,
  RunStatusRes,
  Seek,
  SetEnv,
  Shutdown,
  Start,
  StartRes,
  Stat,
  StatRes,
  Symlink,
  Truncate,
  Utime,
  WorkerGetMessage,
  WorkerGetMessageRes,
  WorkerPostMessage,
  Write,
  WriteRes,
}

enum ErrorKind: byte {
  NoError = 0,

  // io errors

  NotFound,
  PermissionDenied,
  ConnectionRefused,
  ConnectionReset,
  ConnectionAborted,
  NotConnected,
  AddrInUse,
  AddrNotAvailable,
  BrokenPipe,
  AlreadyExists,
  WouldBlock,
  InvalidInput,
  InvalidData,
  TimedOut,
  Interrupted,
  WriteZero,
  Other,
  UnexpectedEof,
  BadResource,
  CommandFailed,

  // url errors

  EmptyHost,
  IdnaError,
  InvalidPort,
  InvalidIpv4Address,
  InvalidIpv6Address,
  InvalidDomainCharacter,
  RelativeUrlWithoutBase,
  RelativeUrlWithCannotBeABaseBase,
  SetHostOnCannotBeABaseUrl,
  Overflow,

  // hyper errors

  HttpUser,
  HttpClosed,
  HttpCanceled,
  HttpParse,
  HttpOther,
  TooLarge,

  // custom errors
  InvalidUri,
  InvalidSeekMode,
  OpNotAvailable,
  WorkerInitFailed,
  UnixError,
  NoAsyncSupport,
  NoSyncSupport,
  ImportMapError,

  // other kinds
  Diagnostic,
  JSError,
}

table Cwd {}

table CwdRes {
  cwd: string;
}

enum MediaType: byte {
  JavaScript = 0,
  TypeScript,
  Json,
  Unknown
}

table Base {
  cmd_id: uint32;
  sync: bool = false;
  error_kind: ErrorKind = NoError;
  error: string;
  inner: Any;
}

table Start {
  unused: int8;
}

table StartRes {
  cwd: string;
  pid: uint32;
  argv: [string];
  exec_path: string;
  main_module: string; // Absolute URL.
  debug_flag: bool;
  deps_flag: bool;
  types_flag: bool;
  version_flag: bool;
  deno_version: string;
  v8_version: string;
  no_color: bool;
  xeval_delim: string;
}

table FormatError {
  error: string;
}

table FormatErrorRes {
  error: string;
}

// Create worker as host
table CreateWorker {
  specifier: string;
}

table CreateWorkerRes {
  rid: uint32;
}

table HostGetWorkerClosed {
  rid: uint32;
}

// Get message from guest worker as host
table HostGetMessage {
  rid: uint32;
}

table HostGetMessageRes {
  data: [ubyte];
}

// Post message to guest worker as host
table HostPostMessage {
  rid: uint32;
  // data passed thru the zero-copy data parameter.
}

// Get message from host as guest worker
table WorkerGetMessage {
  unused: int8;
}

table WorkerGetMessageRes {
  data: [ubyte];
}

// Post message to host as guest worker
table WorkerPostMessage {
  // data passed thru the zero-copy data parameter.
}

table FetchModuleMetaData {
  specifier: string;
  referrer: string;
}

table FetchModuleMetaDataRes {
  // If it's a non-http module, moduleName and filename will be the same.
  // For http modules, module_name is its resolved http URL, and filename
  // is the location of the locally downloaded source code.
  module_name: string;
  filename: string;
  media_type: MediaType;
  data: [ubyte];
}

table Cache {
  extension: string;
  module_id: string;
  contents: string;
}

table Chdir {
  directory: string;
}

table GlobalTimer {
  timeout: int;
}

table GlobalTimerRes { }

table GlobalTimerStop { }

table Exit {
  code: int;
}

table Environ {}

table SetEnv {
  key: string;
  value: string;
}

table EnvironRes {
  map: [KeyValue];
}

table KeyValue {
  key: string;
  value: string;
}

table Permissions {}

table PermissionRevoke {
  permission: string;
}

table PermissionsRes {
  run: bool;
  read: bool;
  write: bool;
  net: bool;
  env: bool;
  hrtime: bool;
}

// Note this represents The WHOLE header of an http message, not just the key
// value pairs. That means it includes method and url for Requests and status
// for responses. This is why it is singular "Header" instead of "Headers".
table HttpHeader {
  is_request: bool;
  // Request only:
  method: string;
  url: string;
  // Response only:
  status: uint16;
  // Both:
  fields: [KeyValue];
}

table Fetch {
  header: HttpHeader;
}

table FetchRes {
  header: HttpHeader;
  body_rid: uint32;
}

table MakeTempDir {
  dir: string;
  prefix: string;
  suffix: string;
}

table MakeTempDirRes {
  path: string;
}

table Mkdir {
  path: string;
  recursive: bool;
  mode: uint; // Specified by https://godoc.org/os#FileMode
}

table Chmod {
  path: string;
  mode: uint; // Specified by https://godoc.org/os#FileMode
}

table Chown {
  path: string;
  uid: uint;
  gid: uint;  // Specified by https://godoc.org/os#Chown
}

table Remove {
  path: string;
  recursive: bool;
}

table ReadDir {
  path: string;
}

table ReadDirRes {
  entries: [StatRes];
}

table CopyFile {
  from: string;
  to: string;
}

table Rename {
  oldpath: string;
  newpath: string;
}

table Readlink {
  name: string;
}

table ReadlinkRes {
  path: string;
}

table ReplStart {
  history_file: string;
  // TODO add config
}

table ReplStartRes {
  rid: uint32;
}

table ReplReadline {
  rid: uint32;
  prompt: string;
}

table ReplReadlineRes {
  line: string;
}

table Resources {}

table Resource {
  rid: uint32;
  repr: string;
}

table ResourcesRes {
  resources: [Resource];
}

table Symlink {
  oldname: string;
  newname: string;
}

table Link {
  oldname: string;
  newname: string;
}

table Stat {
  filename: string;
  lstat: bool;
}

table StatRes {
  is_file: bool;
  is_symlink: bool;
  len: ulong;
  modified:ulong;
  accessed:ulong;
  created:ulong;
  mode: uint;
  has_mode: bool; // false on windows
  name: string;
}

table Truncate {
  name: string;
  len: uint;
}

table Utime {
  filename: string;
  atime: uint64;
  mtime: uint64;
}

table Open {
  filename: string;
  perm: uint;
  mode: string;
}

table OpenRes {
  rid: uint32;
}

table Read {
  rid: uint32;
  // (ptr, len) is passed as second parameter to Deno.core.send().
}

table ReadRes {
  nread: uint;
  eof: bool;
}

table Write {
  rid: uint32;
}

table WriteRes {
  nbyte: uint;
}

table Close {
  rid: uint32;
}

table Kill {
  pid: int32;
  signo: int32;
}

table Shutdown {
  rid: uint32;
  how: uint;
}

table Listen {
  network: string;
  address: string;
}

table ListenRes {
  rid: uint32;
}

table Accept {
  rid: uint32;
}

table Dial {
  network: string;
  address: string;
}

// Response to Accept and Dial.
table NewConn {
  rid: uint32;
  remote_addr: string;
  local_addr: string;
}

table Metrics {}

table MetricsRes {
  ops_dispatched: uint64;
  ops_completed: uint64;
  bytes_sent_control: uint64;
  bytes_sent_data: uint64;
  bytes_received: uint64;
}

enum ProcessStdio: byte { Inherit, Piped, Null }

table Run {
  args: [string];
  cwd: string;
  env: [KeyValue];
  stdin: ProcessStdio;
  stdout: ProcessStdio;
  stderr: ProcessStdio;
}

table RunRes {
  rid: uint32;
  pid: uint32;
  // The following stdio rids are only valid if "Piped" was specified for the
  // corresponding stdio stream. The caller MUST issue a close op for all valid
  // stdio streams.
  stdin_rid: uint32;
  stdout_rid: uint32;
  stderr_rid: uint32;
}

table RunStatus {
  rid: uint32;
}

table RunStatusRes {
  got_signal: bool;
  exit_code: int;
  exit_signal: int;
}

table Now {}

table NowRes {
  seconds: uint64;
  subsec_nanos: uint32;
}

table IsTTY {}

table IsTTYRes {
  stdin: bool;
  stdout: bool;
  stderr: bool;
}

table Seek {
  rid: uint32;
  offset: int;
  whence: uint;
}

table GetRandomValues {}

root_type Base;