1 files changed, 148 insertions, 0 deletions
diff --git a/dom/media/webaudio/blink/HRTFDatabaseLoader.h b/dom/media/webaudio/blink/HRTFDatabaseLoader.h
new file mode 100644
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--- /dev/null
+++ b/dom/media/webaudio/blink/HRTFDatabaseLoader.h
@@ -0,0 +1,148 @@
+/*
+ * 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
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * 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 "nsHashKeys.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/Mutex.h"
+#include "HRTFDatabase.h"
+
+template <class EntryType> class nsTHashtable;
+template <class T> class nsAutoRef;
+
+namespace WebCore {
+
+// HRTFDatabaseLoader will asynchronously load the default HRTFDatabase in a new thread.
+
+class HRTFDatabaseLoader {
+public:
+    // 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 already_AddRefed<HRTFDatabaseLoader> createAndLoadAsynchronouslyIfNecessary(float sampleRate);
+
+    // AddRef and Release may be called from any thread.
+    void AddRef()
+    {
+#if defined(DEBUG) || defined(NS_BUILD_REFCNT_LOGGING)
+        int count =
+#endif
+          ++m_refCnt;
+        MOZ_ASSERT(count > 0, "invalid ref count");
+        NS_LOG_ADDREF(this, count, "HRTFDatabaseLoader", sizeof(*this));
+    }
+
+    void Release()
+    {
+        // The last reference can't be removed on a non-main thread because
+        // the object can be accessed on the main thread from the hash
+        // table via createAndLoadAsynchronouslyIfNecessary().
+        int count = m_refCnt;
+        MOZ_ASSERT(count > 0, "extra release");
+        // Optimization attempt to possibly skip proxying the release to the
+        // main thread.
+        if (count != 1 && m_refCnt.compareExchange(count, count - 1)) {
+            NS_LOG_RELEASE(this, count - 1, "HRTFDatabaseLoader");
+            return;
+        }
+
+        ProxyRelease();
+    }
+
+    // Returns true once the default database has been completely loaded.
+    bool isLoaded() const;
+
+    // waitForLoaderThreadCompletion() may be called more than once,
+    // on any thread except m_databaseLoaderThread.
+    void waitForLoaderThreadCompletion();
+    
+    HRTFDatabase* database() { return m_hrtfDatabase.get(); }
+
+    float databaseSampleRate() const { return m_databaseSampleRate; }
+
+    static void shutdown();
+    
+    // Called in asynchronous loading thread.
+    void load();
+
+    // Sums the size of all cached database loaders.
+    static size_t sizeOfLoaders(mozilla::MallocSizeOf aMallocSizeOf);
+
+private:
+    // Both constructor and destructor must be called from the main thread.
+    explicit HRTFDatabaseLoader(float sampleRate);
+    ~HRTFDatabaseLoader();
+
+    size_t sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
+
+    void ProxyRelease(); // any thread
+    void MainThreadRelease(); // main thread only
+    class ProxyReleaseEvent;
+
+    // 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();
+
+    // Map from sample-rate to loader.
+    class LoaderByRateEntry : public nsFloatHashKey {
+    public:
+        explicit LoaderByRateEntry(KeyTypePointer aKey)
+            : nsFloatHashKey(aKey)
+            , mLoader() // so PutEntry() will zero-initialize
+        {
+        }
+
+        size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
+        {
+            return mLoader ? mLoader->sizeOfIncludingThis(aMallocSizeOf) : 0;
+        }
+
+        HRTFDatabaseLoader* mLoader;
+    };
+
+    // Keeps track of loaders on a per-sample-rate basis.
+    static nsTHashtable<LoaderByRateEntry> *s_loaderMap; // singleton
+
+    mozilla::Atomic<int> m_refCnt;
+
+    nsAutoRef<HRTFDatabase> m_hrtfDatabase;
+
+    // Holding a m_threadLock is required when accessing m_databaseLoaderThread.
+    mozilla::Mutex m_threadLock;
+    PRThread* m_databaseLoaderThread;
+
+    float m_databaseSampleRate;
+};
+
+} // namespace WebCore
+
+#endif // HRTFDatabaseLoader_h