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_MEDIA_MIDI_HOST_H_
6#define CONTENT_BROWSER_MEDIA_MIDI_HOST_H_
7
8#include <vector>
9
10#include "base/gtest_prod_util.h"
11#include "base/memory/ref_counted.h"
12#include "base/memory/scoped_ptr.h"
13#include "base/memory/scoped_vector.h"
14#include "content/common/content_export.h"
15#include "content/public/browser/browser_message_filter.h"
16#include "content/public/browser/browser_thread.h"
17#include "media/midi/midi_manager.h"
18
19namespace media {
20class MidiManager;
21class MidiMessageQueue;
22}
23
24namespace content {
25
26class CONTENT_EXPORT MidiHost
27    : public BrowserMessageFilter,
28      public media::MidiManagerClient {
29 public:
30  // Called from UI thread from the owner of this object.
31  MidiHost(int renderer_process_id, media::MidiManager* midi_manager);
32
33  // BrowserMessageFilter implementation.
34  virtual void OnDestruct() const OVERRIDE;
35  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
36
37  // MidiManagerClient implementation.
38  virtual void CompleteStartSession(int client_id,
39                                    media::MidiResult result) OVERRIDE;
40  virtual void ReceiveMidiData(uint32 port,
41                               const uint8* data,
42                               size_t length,
43                               double timestamp) OVERRIDE;
44  virtual void AccumulateMidiBytesSent(size_t n) OVERRIDE;
45
46  // Start session to access MIDI hardware.
47  void OnStartSession(int client_id);
48
49  // Data to be sent to a MIDI output port.
50  void OnSendData(uint32 port,
51                  const std::vector<uint8>& data,
52                  double timestamp);
53
54 private:
55  FRIEND_TEST_ALL_PREFIXES(MidiHostTest, IsValidWebMIDIData);
56  friend class base::DeleteHelper<MidiHost>;
57  friend class BrowserThread;
58
59  virtual ~MidiHost();
60
61  // Returns true if |data| fulfills the requirements of MidiOutput.send API
62  // defined in the WebMIDI spec.
63  // - |data| must be any number of complete MIDI messages (data abbreviation
64  //    called "running status" is disallowed).
65  // - 1-byte MIDI realtime messages can be placed at any position of |data|.
66  static bool IsValidWebMIDIData(const std::vector<uint8>& data);
67
68  int renderer_process_id_;
69
70  // Represents if the renderer has a permission to send/receive MIDI SysEX
71  // messages.
72  bool has_sys_ex_permission_;
73
74  // |midi_manager_| talks to the platform-specific MIDI APIs.
75  // It can be NULL if the platform (or our current implementation)
76  // does not support MIDI.  If not supported then a call to
77  // OnRequestAccess() will always refuse access and a call to
78  // OnSendData() will do nothing.
79  media::MidiManager* const midi_manager_;
80
81  // Buffers where data sent from each MIDI input port is stored.
82  ScopedVector<media::MidiMessageQueue> received_messages_queues_;
83
84  // The number of bytes sent to the platform-specific MIDI sending
85  // system, but not yet completed.
86  size_t sent_bytes_in_flight_;
87
88  // The number of bytes successfully sent since the last time
89  // we've acknowledged back to the renderer.
90  size_t bytes_sent_since_last_acknowledgement_;
91
92  // Protects access to |sent_bytes_in_flight_|.
93  base::Lock in_flight_lock_;
94
95  DISALLOW_COPY_AND_ASSIGN(MidiHost);
96};
97
98}  // namespace content
99
100#endif  // CONTENT_BROWSER_MEDIA_MIDI_HOST_H_
101