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