michael@0: /*
michael@0:  * Copyright (C) 2010 Google Inc. All rights reserved.
michael@0:  *
michael@0:  * Redistribution and use in source and binary forms, with or without
michael@0:  * modification, are permitted provided that the following conditions
michael@0:  * are met:
michael@0:  *
michael@0:  * 1.  Redistributions of source code must retain the above copyright
michael@0:  *     notice, this list of conditions and the following disclaimer.
michael@0:  * 2.  Redistributions in binary form must reproduce the above copyright
michael@0:  *     notice, this list of conditions and the following disclaimer in the
michael@0:  *     documentation and/or other materials provided with the distribution.
michael@0:  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
michael@0:  *     its contributors may be used to endorse or promote products derived
michael@0:  *     from this software without specific prior written permission.
michael@0:  *
michael@0:  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
michael@0:  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
michael@0:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
michael@0:  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
michael@0:  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
michael@0:  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
michael@0:  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
michael@0:  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
michael@0:  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0:  */
michael@0: 
michael@0: #ifndef HRTFDatabaseLoader_h
michael@0: #define HRTFDatabaseLoader_h
michael@0: 
michael@0: #include "nsHashKeys.h"
michael@0: #include "mozilla/RefPtr.h"
michael@0: #include "mozilla/MemoryReporting.h"
michael@0: #include "mozilla/Mutex.h"
michael@0: #include "HRTFDatabase.h"
michael@0: 
michael@0: template <class EntryType> class nsTHashtable;
michael@0: template <class T> class nsAutoRef;
michael@0: 
michael@0: namespace WebCore {
michael@0: 
michael@0: // HRTFDatabaseLoader will asynchronously load the default HRTFDatabase in a new thread.
michael@0: 
michael@0: class HRTFDatabaseLoader {
michael@0: public:
michael@0:     // Lazily creates a HRTFDatabaseLoader (if not already created) for the given sample-rate
michael@0:     // and starts loading asynchronously (when created the first time).
michael@0:     // Returns the HRTFDatabaseLoader.
michael@0:     // Must be called from the main thread.
michael@0:     static mozilla::TemporaryRef<HRTFDatabaseLoader> createAndLoadAsynchronouslyIfNecessary(float sampleRate);
michael@0: 
michael@0:     // AddRef and Release may be called from any thread.
michael@0:     void AddRef()
michael@0:     {
michael@0: #if defined(DEBUG) || defined(NS_BUILD_REFCNT_LOGGING)
michael@0:         int count =
michael@0: #endif
michael@0:           ++m_refCnt;
michael@0:         MOZ_ASSERT(count > 0, "invalid ref count");
michael@0:         NS_LOG_ADDREF(this, count, "HRTFDatabaseLoader", sizeof(*this));
michael@0:     }
michael@0: 
michael@0:     void Release()
michael@0:     {
michael@0:         // The last reference can't be removed on a non-main thread because
michael@0:         // the object can be accessed on the main thread from the hash
michael@0:         // table via createAndLoadAsynchronouslyIfNecessary().
michael@0:         int count = m_refCnt;
michael@0:         MOZ_ASSERT(count > 0, "extra release");
michael@0:         // Optimization attempt to possibly skip proxying the release to the
michael@0:         // main thread.
michael@0:         if (count != 1 && m_refCnt.compareExchange(count, count - 1)) {
michael@0:             NS_LOG_RELEASE(this, count - 1, "HRTFDatabaseLoader");
michael@0:             return;
michael@0:         }
michael@0: 
michael@0:         ProxyRelease();
michael@0:     }
michael@0: 
michael@0:     // Returns true once the default database has been completely loaded.
michael@0:     bool isLoaded() const;
michael@0: 
michael@0:     // waitForLoaderThreadCompletion() may be called more than once,
michael@0:     // on any thread except m_databaseLoaderThread.
michael@0:     void waitForLoaderThreadCompletion();
michael@0:     
michael@0:     HRTFDatabase* database() { return m_hrtfDatabase.get(); }
michael@0: 
michael@0:     float databaseSampleRate() const { return m_databaseSampleRate; }
michael@0: 
michael@0:     static void shutdown();
michael@0:     
michael@0:     // Called in asynchronous loading thread.
michael@0:     void load();
michael@0: 
michael@0:     size_t sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
michael@0: 
michael@0: private:
michael@0:     // Both constructor and destructor must be called from the main thread.
michael@0:     explicit HRTFDatabaseLoader(float sampleRate);
michael@0:     ~HRTFDatabaseLoader();
michael@0:     
michael@0:     void ProxyRelease(); // any thread
michael@0:     void MainThreadRelease(); // main thread only
michael@0:     class ProxyReleaseEvent;
michael@0: 
michael@0:     // If it hasn't already been loaded, creates a new thread and initiates asynchronous loading of the default database.
michael@0:     // This must be called from the main thread.
michael@0:     void loadAsynchronously();
michael@0: 
michael@0:     // Map from sample-rate to loader.
michael@0:     class LoaderByRateEntry : public nsFloatHashKey {
michael@0:     public:
michael@0:         LoaderByRateEntry(KeyTypePointer aKey)
michael@0:             : nsFloatHashKey(aKey)
michael@0:             , mLoader() // so PutEntry() will zero-initialize
michael@0:         {
michael@0:         }
michael@0:         HRTFDatabaseLoader* mLoader;
michael@0:     };
michael@0: 
michael@0:     static PLDHashOperator shutdownEnumFunc(LoaderByRateEntry *entry,
michael@0:                                             void* unused);
michael@0: 
michael@0:     // Keeps track of loaders on a per-sample-rate basis.
michael@0:     static nsTHashtable<LoaderByRateEntry> *s_loaderMap; // singleton
michael@0: 
michael@0:     mozilla::Atomic<int> m_refCnt;
michael@0: 
michael@0:     nsAutoRef<HRTFDatabase> m_hrtfDatabase;
michael@0: 
michael@0:     // Holding a m_threadLock is required when accessing m_databaseLoaderThread.
michael@0:     mozilla::Mutex m_threadLock;
michael@0:     PRThread* m_databaseLoaderThread;
michael@0: 
michael@0:     float m_databaseSampleRate;
michael@0: };
michael@0: 
michael@0: } // namespace WebCore
michael@0: 
michael@0: #endif // HRTFDatabaseLoader_h