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      1 /*
      2  * Copyright (C) 2010 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  *
      8  * 1.  Redistributions of source code must retain the above copyright
      9  *     notice, this list of conditions and the following disclaimer.
     10  * 2.  Redistributions in binary form must reproduce the above copyright
     11  *     notice, this list of conditions and the following disclaimer in the
     12  *     documentation and/or other materials provided with the distribution.
     13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
     14  *     its contributors may be used to endorse or promote products derived
     15  *     from this software without specific prior written permission.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
     18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
     21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #ifndef HRTFDatabaseLoader_h
     30 #define HRTFDatabaseLoader_h
     31 
     32 #include "platform/audio/HRTFDatabase.h"
     33 #include "public/platform/WebThread.h"
     34 #include "wtf/HashMap.h"
     35 #include "wtf/PassRefPtr.h"
     36 #include "wtf/RefCounted.h"
     37 #include "wtf/RefPtr.h"
     38 #include "wtf/ThreadingPrimitives.h"
     39 
     40 namespace WebCore {
     41 
     42 // HRTFDatabaseLoader will asynchronously load the default HRTFDatabase in a new thread.
     43 
     44 class PLATFORM_EXPORT HRTFDatabaseLoader : public RefCounted<HRTFDatabaseLoader> {
     45 public:
     46     // Lazily creates a HRTFDatabaseLoader (if not already created) for the given sample-rate
     47     // and starts loading asynchronously (when created the first time).
     48     // Returns the HRTFDatabaseLoader.
     49     // Must be called from the main thread.
     50     static PassRefPtr<HRTFDatabaseLoader> createAndLoadAsynchronouslyIfNecessary(float sampleRate);
     51 
     52     // Both constructor and destructor must be called from the main thread.
     53     ~HRTFDatabaseLoader();
     54 
     55     // Returns true once the default database has been completely loaded.
     56     bool isLoaded() const;
     57 
     58     // waitForLoaderThreadCompletion() may be called more than once and is thread-safe.
     59     void waitForLoaderThreadCompletion();
     60 
     61     HRTFDatabase* database() { return m_hrtfDatabase.get(); }
     62 
     63     float databaseSampleRate() const { return m_databaseSampleRate; }
     64 
     65     // Called in asynchronous loading thread.
     66     void load();
     67 
     68 private:
     69     // Both constructor and destructor must be called from the main thread.
     70     explicit HRTFDatabaseLoader(float sampleRate);
     71 
     72     // If it hasn't already been loaded, creates a new thread and initiates asynchronous loading of the default database.
     73     // This must be called from the main thread.
     74     void loadAsynchronously();
     75 
     76     // Map from sample-rate to loader.
     77     typedef HashMap<double, HRTFDatabaseLoader*> LoaderMap;
     78 
     79     // Keeps track of loaders on a per-sample-rate basis.
     80     static LoaderMap* s_loaderMap; // singleton
     81 
     82     OwnPtr<HRTFDatabase> m_hrtfDatabase;
     83 
     84     // Holding a m_threadLock is required when accessing m_databaseLoaderThread since we access it from multiple threads.
     85     Mutex m_threadLock;
     86     OwnPtr<blink::WebThread> m_databaseLoaderThread;
     87 
     88     float m_databaseSampleRate;
     89 };
     90 
     91 } // namespace WebCore
     92 
     93 #endif // HRTFDatabaseLoader_h
     94