content/browser/renderer_host/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_RENDERER_HOST_MEDIA_MIDI_HOST_H_
   6 #define CONTENT_BROWSER_RENDERER_HOST_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,
  36                                  bool* message_was_ok) OVERRIDE;
  37
  38   // MidiManagerClient implementation.
  39   virtual void CompleteStartSession(int client_id,
  40                                     media::MidiResult result) OVERRIDE;
  41   virtual void ReceiveMidiData(uint32 port,
  42                                const uint8* data,
  43                                size_t length,
  44                                double timestamp) OVERRIDE;
  45   virtual void AccumulateMidiBytesSent(size_t n) OVERRIDE;
  46
  47   // Start session to access MIDI hardware.
  48   void OnStartSession(int client_id);
  49
  50   // Data to be sent to a MIDI output port.
  51   void OnSendData(uint32 port,
  52                   const std::vector<uint8>& data,
  53                   double timestamp);
  54
  55  private:
  56   FRIEND_TEST_ALL_PREFIXES(MidiHostTest, IsValidWebMIDIData);
  57   friend class base::DeleteHelper<MidiHost>;
  58   friend class BrowserThread;
  59
  60   virtual ~MidiHost();
  61
  62   // Returns true if |data| fulfills the requirements of MidiOutput.send API
  63   // defined in the WebMIDI spec.
  64   // - |data| must be any number of complete MIDI messages (data abbreviation
  65   //    called "running status" is disallowed).
  66   // - 1-byte MIDI realtime messages can be placed at any position of |data|.
  67   static bool IsValidWebMIDIData(const std::vector<uint8>& data);
  68
  69   int renderer_process_id_;
  70
  71   // Represents if the renderer has a permission to send/receive MIDI SysEX
  72   // messages.
  73   bool has_sys_ex_permission_;
  74
  75   // |midi_manager_| talks to the platform-specific MIDI APIs.
  76   // It can be NULL if the platform (or our current implementation)
  77   // does not support MIDI.  If not supported then a call to
  78   // OnRequestAccess() will always refuse access and a call to
  79   // OnSendData() will do nothing.
  80   media::MidiManager* const midi_manager_;
  81
  82   // Buffers where data sent from each MIDI input port is stored.
  83   ScopedVector<media::MidiMessageQueue> received_messages_queues_;
  84
  85   // The number of bytes sent to the platform-specific MIDI sending
  86   // system, but not yet completed.
  87   size_t sent_bytes_in_flight_;
  88
  89   // The number of bytes successfully sent since the last time
  90   // we've acknowledged back to the renderer.
  91   size_t bytes_sent_since_last_acknowledgement_;
  92
  93   // Protects access to |sent_bytes_in_flight_|.
  94   base::Lock in_flight_lock_;
  95
  96   DISALLOW_COPY_AND_ASSIGN(MidiHost);
  97 };
  98
  99 }  // namespace content
 100
 101 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_MIDI_HOST_H_