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      1 // Copyright (c) 2012 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_MEDIA_INTERNALS_H_
      6 #define CONTENT_BROWSER_MEDIA_MEDIA_INTERNALS_H_
      7 
      8 #include <string>
      9 #include <vector>
     10 
     11 #include "base/callback_forward.h"
     12 #include "base/compiler_specific.h"
     13 #include "base/lazy_instance.h"
     14 #include "base/strings/string16.h"
     15 #include "base/synchronization/lock.h"
     16 #include "base/values.h"
     17 #include "content/common/content_export.h"
     18 #include "media/audio/audio_logging.h"
     19 
     20 namespace media {
     21 class AudioParameters;
     22 struct MediaLogEvent;
     23 }
     24 
     25 namespace content {
     26 
     27 // This class stores information about currently active media.
     28 class CONTENT_EXPORT MediaInternals
     29     : NON_EXPORTED_BASE(public media::AudioLogFactory) {
     30  public:
     31   static MediaInternals* GetInstance();
     32 
     33   virtual ~MediaInternals();
     34 
     35   // Called when a MediaEvent occurs.
     36   void OnMediaEvents(int render_process_id,
     37                      const std::vector<media::MediaLogEvent>& events);
     38 
     39   // Called with the update string.
     40   typedef base::Callback<void(const base::string16&)> UpdateCallback;
     41 
     42   // Add/remove update callbacks (see above).  Must be called on the IO thread.
     43   void AddUpdateCallback(const UpdateCallback& callback);
     44   void RemoveUpdateCallback(const UpdateCallback& callback);
     45 
     46   // Sends all cached data to each registered UpdateCallback.
     47   void SendEverything();
     48 
     49   // AudioLogFactory implementation.  Safe to call from any thread.
     50   virtual scoped_ptr<media::AudioLog> CreateAudioLog(
     51       AudioComponent component) OVERRIDE;
     52 
     53  private:
     54   friend class AudioLogImpl;
     55   friend class MediaInternalsTest;
     56   friend struct base::DefaultLazyInstanceTraits<MediaInternals>;
     57 
     58   MediaInternals();
     59 
     60   // Sends |update| to each registered UpdateCallback.  Safe to call from any
     61   // thread, but will forward to the IO thread.
     62   void SendUpdate(const base::string16& update);
     63 
     64   // Caches |value| under |cache_key| so that future SendEverything() calls will
     65   // include the current data.  Calls JavaScript |function|(|value|) for each
     66   // registered UpdateCallback.  SendUpdateAndPurgeCache() is similar but purges
     67   // the cache entry after completion instead.
     68   void SendUpdateAndCache(const std::string& cache_key,
     69                           const std::string& function,
     70                           const base::DictionaryValue* value);
     71   void SendUpdateAndPurgeCache(const std::string& cache_key,
     72                                const std::string& function,
     73                                const base::DictionaryValue* value);
     74   // Must only be accessed on the IO thread.
     75   std::vector<UpdateCallback> update_callbacks_;
     76 
     77   // All variables below must be accessed under |lock_|.
     78   base::Lock lock_;
     79   base::DictionaryValue cached_data_;
     80   int owner_ids_[AUDIO_COMPONENT_MAX];
     81 
     82   DISALLOW_COPY_AND_ASSIGN(MediaInternals);
     83 };
     84 
     85 } // namespace content
     86 
     87 #endif  // CONTENT_BROWSER_MEDIA_MEDIA_INTERNALS_H_
     88