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