media/midi/midi_service.mojom

// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

module midi.mojom;

import "mojo/public/mojom/base/time.mojom";

enum Result {
  NOT_INITIALIZED,
  OK,
  NOT_SUPPORTED,
  INITIALIZATION_ERROR,

  // New code should be inserted here so that existing members keep the same
  // assigned value. //tools/metrics/histograms/histograms.xml contains a enum
  // entry that should be consistent with enum Result.

  // |MAX| is used in content/common/media/midi_messages.h with
  // IPC_ENUM_TRAITS_MAX_VALUE macro. Keep the value up to date. Otherwise
  // a new value can not be passed to the renderer.
  // TODO(toyoshim): Remove |MAX| once IPC is replaced with Mojo.
  // http://crbug.com/582327
  MAX = INITIALIZATION_ERROR,
};

enum PortState {
  DISCONNECTED,
  CONNECTED,
  OPENED,
  // TODO(toyosim): Remove |LAST| once IPC is replaced with Mojo.
  // http://crbug.com/582327
  LAST = OPENED,
};

struct PortInfo {
  string id;
  string manufacturer;
  string name;
  string version;
  PortState state;
};

// Interface for MIDI related browser to renderer messages.
interface MidiSessionClient {
  // These functions are called in 2 cases:
  //  (1) Just before calling |SessionStarted|, to notify the recipient about
  //      existing ports.
  //  (2) To notify the recipient that a new device was connected and that new
  //      ports have been created.
  AddInputPort(PortInfo info);
  AddOutputPort(PortInfo info);

  // Used to notify clients when a device is disconnected or reconnected. The
  // ports correspond to ports already sent to the client using AddInputPort/
  // AddOutputPort.
  SetInputPortState(uint32 port, PortState state);
  SetOutputPortState(uint32 port, PortState state);

  // Called in response to StartSession and indicates if a connection with
  // MIDI hardware was successfully made.
  SessionStarted(Result result);

  // Used to inform the client incrementally of how many bytes have been
  // successfully sent. This is only called after the client calls SendData().
  AcknowledgeSentData(uint32 bytes);

  // Called to send MIDI data to the client.
  DataReceived(uint32 port,
               array<uint8> data,
               mojo_base.mojom.TimeTicks timestamp);
};

// Interface used by the renderer to start a MIDI session in the browser.
interface MidiSessionProvider {
  // Start session to access MIDI hardware.
  StartSession(MidiSession& request, MidiSessionClient client);
};

// Represents an active MIDI session.
interface MidiSession {
  // Send data to a MIDI output port. The output port should be a port already
  // sent to the client (via AddOutputPort).
  SendData(uint32 port, array<uint8> data, mojo_base.mojom.TimeTicks timestamp);
};