media/midi/usb_midi_device.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef MEDIA_MIDI_USB_MIDI_DEVICE_H_
   6 #define MEDIA_MIDI_USB_MIDI_DEVICE_H_
   7
   8 #include <vector>
   9
  10 #include "base/basictypes.h"
  11 #include "base/callback.h"
  12 #include "base/memory/scoped_vector.h"
  13 #include "base/time/time.h"
  14 #include "media/base/media_export.h"
  15
  16 namespace media {
  17
  18 class UsbMidiDevice;
  19
  20 // Delegate class for UsbMidiDevice.
  21 // Each method is called when an corresponding event arrives at the device.
  22 class MEDIA_EXPORT UsbMidiDeviceDelegate {
  23  public:
  24   virtual ~UsbMidiDeviceDelegate() {}
  25
  26   // Called when USB-MIDI data arrives at |device|.
  27   virtual void ReceiveUsbMidiData(UsbMidiDevice* device,
  28                                   int endpoint_number,
  29                                   const uint8* data,
  30                                   size_t size,
  31                                   base::TimeTicks time) = 0;
  32 };
  33
  34 // UsbMidiDevice represents a USB-MIDI device.
  35 // This is an interface class and each platform-dependent implementation class
  36 // will be a derived class.
  37 class MEDIA_EXPORT UsbMidiDevice {
  38  public:
  39   typedef ScopedVector<UsbMidiDevice> Devices;
  40
  41   // Factory class for USB-MIDI devices.
  42   // Each concrete implementation will find and create devices
  43   // in platform-dependent way.
  44   class Factory {
  45    public:
  46     typedef base::Callback<void(bool result, Devices* devices)> Callback;
  47     virtual ~Factory() {}
  48     // Enumerates devices.
  49     // Devices that have no USB-MIDI interfaces can be omitted.
  50     // When the operation succeeds, |callback| will be called with |true| and
  51     // devices.
  52     // Otherwise |callback| will be called with |false| and empty devices.
  53     // When this factory is destroyed during the operation, the operation
  54     // will be canceled silently (i.e. |callback| will not be called).
  55     // This function can be called at most once per instance.
  56     virtual void EnumerateDevices(UsbMidiDeviceDelegate* delegate,
  57                                   Callback callback) = 0;
  58   };
  59
  60   virtual ~UsbMidiDevice() {}
  61
  62   // Returns the descriptor of this device.
  63   virtual std::vector<uint8> GetDescriptor() = 0;
  64
  65   // Sends |data| to the given USB endpoint of this device.
  66   virtual void Send(int endpoint_number, const std::vector<uint8>& data) = 0;
  67 };
  68
  69 }  // namespace media
  70
  71 #endif  // MEDIA_MIDI_USB_MIDI_DEVICE_H_