content/browser/media/media_internals.h

   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_