content/browser/media/midi_host.h

   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 "base/synchronization/lock.h"
  15 #include "content/common/content_export.h"
  16 #include "content/public/browser/browser_message_filter.h"
  17 #include "content/public/browser/browser_thread.h"
  18 #include "media/midi/midi_manager.h"
  19 #include "media/midi/midi_port_info.h"
  20
  21 namespace media {
  22 namespace midi {
  23 class MidiManager;
  24 class MidiMessageQueue;
  25 }
  26 }
  27
  28 namespace content {
  29
  30 class CONTENT_EXPORT MidiHost : public BrowserMessageFilter,
  31                                 public media::midi::MidiManagerClient {
  32  public:
  33   // Called from UI thread from the owner of this object.
  34   MidiHost(int renderer_process_id, media::midi::MidiManager* midi_manager);
  35
  36   // BrowserMessageFilter implementation.
  37   void OnDestruct() const override;
  38   bool OnMessageReceived(const IPC::Message& message) override;
  39
  40   // MidiManagerClient implementation.
  41   void CompleteStartSession(media::midi::Result result) override;
  42   void AddInputPort(const media::midi::MidiPortInfo& info) override;
  43   void AddOutputPort(const media::midi::MidiPortInfo& info) override;
  44   void SetInputPortState(uint32 port,
  45                          media::midi::MidiPortState state) override;
  46   void SetOutputPortState(uint32 port,
  47                           media::midi::MidiPortState state) override;
  48   void ReceiveMidiData(uint32 port,
  49                        const uint8* data,
  50                        size_t length,
  51                        double timestamp) override;
  52   void AccumulateMidiBytesSent(size_t n) override;
  53
  54   // Start session to access MIDI hardware.
  55   void OnStartSession();
  56
  57   // Data to be sent to a MIDI output port.
  58   void OnSendData(uint32 port,
  59                   const std::vector<uint8>& data,
  60                   double timestamp);
  61
  62   void OnEndSession();
  63
  64  protected:
  65   ~MidiHost() override;
  66
  67  private:
  68   FRIEND_TEST_ALL_PREFIXES(MidiHostTest, IsValidWebMIDIData);
  69   friend class base::DeleteHelper<MidiHost>;
  70   friend class BrowserThread;
  71
  72   // Returns true if |data| fulfills the requirements of MidiOutput.send API
  73   // defined in the WebMIDI spec.
  74   // - |data| must be any number of complete MIDI messages (data abbreviation
  75   //    called "running status" is disallowed).
  76   // - 1-byte MIDI realtime messages can be placed at any position of |data|.
  77   static bool IsValidWebMIDIData(const std::vector<uint8>& data);
  78
  79   int renderer_process_id_;
  80
  81   // Represents if the renderer has a permission to send/receive MIDI SysEX
  82   // messages.
  83   bool has_sys_ex_permission_;
  84
  85   // Represents if a session is requested to start.
  86   bool is_session_requested_;
  87
  88   // |midi_manager_| talks to the platform-specific MIDI APIs.
  89   // It can be NULL if the platform (or our current implementation)
  90   // does not support MIDI.  If not supported then a call to
  91   // OnRequestAccess() will always refuse access and a call to
  92   // OnSendData() will do nothing.
  93   media::midi::MidiManager* const midi_manager_;
  94
  95   // Buffers where data sent from each MIDI input port is stored.
  96   ScopedVector<media::midi::MidiMessageQueue> received_messages_queues_;
  97
  98   // Protects access to |received_messages_queues_|;
  99   base::Lock messages_queues_lock_;
 100
 101   // The number of bytes sent to the platform-specific MIDI sending
 102   // system, but not yet completed.
 103   size_t sent_bytes_in_flight_;
 104
 105   // The number of bytes successfully sent since the last time
 106   // we've acknowledged back to the renderer.
 107   size_t bytes_sent_since_last_acknowledgement_;
 108
 109   // Protects access to |sent_bytes_in_flight_|.
 110   base::Lock in_flight_lock_;
 111
 112   // How many output port exists.
 113   uint32 output_port_count_;
 114
 115   // Protects access to |output_port_count_|.
 116   base::Lock output_port_count_lock_;
 117
 118   DISALLOW_COPY_AND_ASSIGN(MidiHost);
 119 };
 120
 121 }  // namespace content
 122
 123 #endif  // CONTENT_BROWSER_MEDIA_MIDI_HOST_H_