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      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_
    100