Support multiple HRTFDatabases for different sample-rates

Source/core/platform/audio/HRTFDatabaseLoader.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 12 matching lines @@
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef HRTFDatabaseLoader_h
 #define HRTFDatabaseLoader_h
 
 #include "core/platform/audio/HRTFDatabase.h"
-#include <wtf/PassRefPtr.h>
-#include <wtf/RefCounted.h>
-#include <wtf/RefPtr.h>
-#include <wtf/Threading.h>
+#include "wtf/HashMap.h"
+#include "wtf/PassRefPtr.h"
+#include "wtf/RefCounted.h"
+#include "wtf/RefPtr.h"
+#include "wtf/Threading.h"
 
 namespace WebCore {
 
 // HRTFDatabaseLoader will asynchronously load the default HRTFDatabase in a new thread.
 
 class HRTFDatabaseLoader : public RefCounted<HRTFDatabaseLoader> {
 public:
-    // Lazily creates the singleton HRTFDatabaseLoader (if not already created) and starts loading asynchronously (when created the first time).
-    // Returns the singleton HRTFDatabaseLoader.
+    // Lazily creates a HRTFDatabaseLoader (if not already created) for the given sample-rate
+    // and starts loading asynchronously (when created the first time).
+    // Returns the HRTFDatabaseLoader.
     // Must be called from the main thread.
     static PassRefPtr<HRTFDatabaseLoader> createAndLoadAsynchronouslyIfNecessary(float sampleRate);
 
-    // Returns the singleton HRTFDatabaseLoader.
-    static HRTFDatabaseLoader* loader() { return s_loader; }
-    
     // Both constructor and destructor must be called from the main thread.
     ~HRTFDatabaseLoader();
     
     // Returns true once the default database has been completely loaded.
     bool isLoaded() const;
 
     // waitForLoaderThreadCompletion() may be called more than once and is thread-safe.
     void waitForLoaderThreadCompletion();
     
     HRTFDatabase* database() { return m_hrtfDatabase.get(); }
 
     float databaseSampleRate() const { return m_databaseSampleRate; }
     
     // Called in asynchronous loading thread.
     void load();
 
-    // defaultHRTFDatabase() gives access to the loaded database.
-    // This can be called from any thread, but it is the callers responsibilty to call this while the context (and thus HRTFDatabaseLoader)
-    // is still alive.  Otherwise this will return 0.
-    static HRTFDatabase* defaultHRTFDatabase();
+    void reportMemoryUsage(MemoryObjectInfo*) const;
 
-    void reportMemoryUsage(MemoryObjectInfo*) const;
+    // Map from sample-rate to loader.
+    class LoaderMap : public HashMap<double, HRTFDatabaseLoader*> {
+    public:
+        void reportMemoryUsage(MemoryObjectInfo*) const;
+    };
+
+    static HRTFDatabaseLoader::LoaderMap* loaderMap() { return s_loaderMap; }
 
 private:
     // Both constructor and destructor must be called from the main thread.
     explicit HRTFDatabaseLoader(float sampleRate);
     
     // If it hasn't already been loaded, creates a new thread and initiates asynchronous loading of the default database.
     // This must be called from the main thread.
     void loadAsynchronously();
 
-    static HRTFDatabaseLoader* s_loader; // singleton
+    // Keeps track of loaders on a per-sample-rate basis.
+    static LoaderMap* s_loaderMap; // singleton
+
     OwnPtr<HRTFDatabase> m_hrtfDatabase;
 
     // Holding a m_threadLock is required when accessing m_databaseLoaderThread.
     Mutex m_threadLock;
     ThreadIdentifier m_databaseLoaderThread;
 
     float m_databaseSampleRate;
 };
 
 } // namespace WebCore
 
 #endif // HRTFDatabaseLoader_h