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 "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
  19 namespace media {
  20 class MidiManager;
  21 class MidiMessageQueue;
  22 }
  23
  24 namespace content {
  25
  26 class 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_