1// Copyright (c) 2013 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 CONTENT_BROWSER_RENDERER_HOST_MEDIA_MIDI_HOST_H_
6#define CONTENT_BROWSER_RENDERER_HOST_MEDIA_MIDI_HOST_H_
7
8#include "base/memory/ref_counted.h"
9#include "base/memory/scoped_ptr.h"
10#include "content/common/content_export.h"
11#include "content/public/browser/browser_message_filter.h"
12#include "content/public/browser/browser_thread.h"
13#include "media/midi/midi_manager.h"
14
15namespace media {
16class MIDIManager;
17}
18
19namespace content {
20
21class CONTENT_EXPORT MIDIHost
22    : public BrowserMessageFilter,
23      public media::MIDIManagerClient {
24 public:
25  // Called from UI thread from the owner of this object.
26  MIDIHost(media::MIDIManager* midi_manager);
27
28  // BrowserMessageFilter implementation.
29  virtual void OnChannelClosing() OVERRIDE;
30  virtual void OnDestruct() const OVERRIDE;
31  virtual bool OnMessageReceived(const IPC::Message& message,
32                                 bool* message_was_ok) OVERRIDE;
33
34  // MIDIManagerClient implementation.
35  virtual void ReceiveMIDIData(
36      int port_index,
37      const uint8* data,
38      size_t length,
39      double timestamp) OVERRIDE;
40  virtual void AccumulateMIDIBytesSent(size_t n) OVERRIDE;
41
42  // Start session to access MIDI hardware.
43  void OnStartSession(int client_id);
44
45  // Data to be sent to a MIDI output port.
46  void OnSendData(int port,
47                  const std::vector<uint8>& data,
48                  double timestamp);
49
50 private:
51  friend class base::DeleteHelper<MIDIHost>;
52  friend class BrowserThread;
53
54  virtual ~MIDIHost();
55
56  // |midi_manager_| talks to the platform-specific MIDI APIs.
57  // It can be NULL if the platform (or our current implementation)
58  // does not support MIDI.  If not supported then a call to
59  // OnRequestAccess() will always refuse access and a call to
60  // OnSendData() will do nothing.
61  media::MIDIManager* const midi_manager_;
62
63  // The number of bytes sent to the platform-specific MIDI sending
64  // system, but not yet completed.
65  size_t sent_bytes_in_flight_;
66
67  // The number of bytes successfully sent since the last time
68  // we've acknowledged back to the renderer.
69  size_t bytes_sent_since_last_acknowledgement_;
70
71  // Protects access to |sent_bytes_in_flight_|.
72  base::Lock in_flight_lock_;
73
74  DISALLOW_COPY_AND_ASSIGN(MIDIHost);
75};
76
77}  // namespace content
78
79#endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_MIDI_HOST_H_
80