Caching AudioOutputDevice instances in mixer manager

content/renderer/media/audio_renderer_mixer_manager.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_MEDIA_AUDIO_RENDERER_MIXER_MANAGER_H_
 #define CONTENT_RENDERER_MEDIA_AUDIO_RENDERER_MIXER_MANAGER_H_
 
 #include <map>
+#include <memory>
 #include <string>
-#include <utility>
 
 #include "base/macros.h"
 #include "base/synchronization/lock.h"
 #include "content/common/content_export.h"
 #include "media/audio/audio_device_description.h"
 #include "media/base/audio_parameters.h"
+#include "media/base/audio_renderer_mixer_pool.h"
 #include "media/base/output_device_info.h"
 #include "url/origin.h"
 
 namespace media {
-class AudioHardwareConfig;
 class AudioRendererMixer;
 class AudioRendererMixerInput;
 class AudioRendererSink;
 }
 
 namespace content {
+class AudioRendererSinkCache;
 
 // Manages sharing of an AudioRendererMixer among AudioRendererMixerInputs based
 // on their AudioParameters configuration.  Inputs with the same AudioParameters
 // configuration will share a mixer while a new AudioRendererMixer will be
-// lazily created if one with the exact AudioParameters does not exist.
+// lazily created if one with the exact AudioParameters does not exist. When an
+// AudioRendererMixer is returned by AudioRendererMixerInput, it will be deleted
+// if its only other reference is held by AudioRendererMixerManager.
 //
 // There should only be one instance of AudioRendererMixerManager per render
 // thread.
 //
 // TODO(dalecurtis): Right now we require AudioParameters to be an exact match
 // when we should be able to ignore bits per channel since we're only dealing
 // with floats.  However, bits per channel is currently used to interleave the
 // audio data by AudioOutputDevice::AudioThreadCallback::Process for consumption
 // via the shared memory.  See http://crbug.com/114700.
-class CONTENT_EXPORT AudioRendererMixerManager {
+class CONTENT_EXPORT AudioRendererMixerManager
+    : public media::AudioRendererMixerPool {
  public:
-  AudioRendererMixerManager();
-  ~AudioRendererMixerManager();
+  ~AudioRendererMixerManager() final;
+
+  static std::unique_ptr<AudioRendererMixerManager> Create();
 
   // Creates an AudioRendererMixerInput with the proper callbacks necessary to
   // retrieve an AudioRendererMixer instance from AudioRendererMixerManager.
   // |source_render_frame_id| refers to the RenderFrame containing the entity
   // rendering the audio.  Caller must ensure AudioRendererMixerManager outlives
   // the returned input. |device_id|, |session_id| and |security_origin|
   // identify the output device to use. If |device_id| is empty and |session_id|
   // is nonzero, output device associated with the opened input device
   // designated by |session_id| is used. Otherwise, |session_id| is ignored.
   media::AudioRendererMixerInput* CreateInput(
       int source_render_frame_id,
       int session_id,
       const std::string& device_id,
       const url::Origin& security_origin);
 
-  // Returns a mixer instance based on AudioParameters; an existing one if one
-  // with the provided AudioParameters exists or a new one if not.
-  media::AudioRendererMixer* GetMixer(int source_render_frame_id,
-                                      const media::AudioParameters& params,
-                                      const std::string& device_id,
-                                      const url::Origin& security_origin,
-                                      media::OutputDeviceStatus* device_status);
+  // AudioRendererMixerPool implementation.
 
-  // Remove a mixer instance given a mixer if the only other reference is held
-  // by AudioRendererMixerManager.  Every AudioRendererMixer owner must call
-  // this method when it's done with a mixer.
-  void RemoveMixer(int source_render_frame_id,
+  media::AudioRendererMixer* GetMixer(
+      int source_render_frame_id,
+      const media::AudioParameters& params,
+      const std::string& device_id,
+      const url::Origin& security_origin,
+      media::OutputDeviceStatus* device_status) final;
+
+  void ReturnMixer(int source_render_frame_id,
                    const media::AudioParameters& params,
                    const std::string& device_id,
-                   const url::Origin& security_origin);
+                   const url::Origin& security_origin) final;
+
+  media::OutputDeviceInfo GetOutputDeviceInfo(
+      int source_render_frame_id,
+      int session_id,
+      const std::string& device_id,
+      const url::Origin& security_origin) final;
+
+ protected:
+  explicit AudioRendererMixerManager(
+      std::unique_ptr<AudioRendererSinkCache> sink_cache);
 
  private:
   friend class AudioRendererMixerManagerTest;
 
   // Define a key so that only those AudioRendererMixerInputs from the same
   // RenderView, AudioParameters and output device can be mixed together.
   struct MixerKey {
     MixerKey(int source_render_frame_id,
              const media::AudioParameters& params,
              const std::string& device_id,
@@ skipping 34 matching lines @@
       return a.security_origin < b.security_origin;
     }
   };
 
   // Map of MixerKey to <AudioRendererMixer, Count>.  Count allows
   // AudioRendererMixerManager to keep track explicitly (v.s. RefCounted which
   // is implicit) of the number of outstanding AudioRendererMixers.
   struct AudioRendererMixerReference {
     media::AudioRendererMixer* mixer;
     int ref_count;
+    // Mixer sink pointer, to remove a sink from cache upon mixer destruction.
+    const media::AudioRendererSink* sink_ptr;
   };
-  typedef std::map<MixerKey, AudioRendererMixerReference, MixerKeyCompare>
-      AudioRendererMixerMap;
+
+  using AudioRendererMixerMap =
+      std::map<MixerKey, AudioRendererMixerReference, MixerKeyCompare>;
 
   // Active mixers.
   AudioRendererMixerMap mixers_;
   base::Lock mixers_lock_;
 
+  // Mixer sink cache.
+  const std::unique_ptr<AudioRendererSinkCache> sink_cache_;
+
   DISALLOW_COPY_AND_ASSIGN(AudioRendererMixerManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_AUDIO_RENDERER_MIXER_MANAGER_H_