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