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 /*

  * 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.

  */

 #include "HRTFDatabaseLoader.h"

 #include "HRTFDatabase.h"

 using namespace mozilla;

 namespace WebCore {

 // Singleton

 nsTHashtable<HRTFDatabaseLoader::LoaderByRateEntry>*

     HRTFDatabaseLoader::s_loaderMap = nullptr;

 TemporaryRef<HRTFDatabaseLoader> HRTFDatabaseLoader::createAndLoadAsynchronouslyIfNecessary(float sampleRate)

 {

     MOZ_ASSERT(NS_IsMainThread());

     RefPtr<HRTFDatabaseLoader> loader;

     if (!s_loaderMap) {

         s_loaderMap = new nsTHashtable<LoaderByRateEntry>();

     }

     LoaderByRateEntry* entry = s_loaderMap->PutEntry(sampleRate);

     loader = entry->mLoader;

     if (loader) { // existing entry

         MOZ_ASSERT(sampleRate == loader->databaseSampleRate());

         return loader;

     }

     loader = new HRTFDatabaseLoader(sampleRate);

     entry->mLoader = loader;

     loader->loadAsynchronously();

     return loader;

 }

 HRTFDatabaseLoader::HRTFDatabaseLoader(float sampleRate)

     : m_refCnt(0)

     , m_threadLock("HRTFDatabaseLoader")

     , m_databaseLoaderThread(nullptr)

     , m_databaseSampleRate(sampleRate)

 {

     MOZ_ASSERT(NS_IsMainThread());

 }

 HRTFDatabaseLoader::~HRTFDatabaseLoader()

 {

     MOZ_ASSERT(NS_IsMainThread());

     waitForLoaderThreadCompletion();

     m_hrtfDatabase.reset();

     if (s_loaderMap) {

         // Remove ourself from the map.

         s_loaderMap->RemoveEntry(m_databaseSampleRate);

         if (s_loaderMap->Count() == 0) {

             delete s_loaderMap;

             s_loaderMap = nullptr;

         }

     }

 }

 size_t HRTFDatabaseLoader::sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const

 {

     size_t amount = aMallocSizeOf(this);

     // NB: Need to make sure we're not competing with the loader thread.

     const_cast<HRTFDatabaseLoader*>(this)->waitForLoaderThreadCompletion();

     if (m_hrtfDatabase) {

         amount += m_hrtfDatabase->sizeOfIncludingThis(aMallocSizeOf);

     }

     return amount;

 }

 class HRTFDatabaseLoader::ProxyReleaseEvent MOZ_FINAL : public nsRunnable {

 public:

     explicit ProxyReleaseEvent(HRTFDatabaseLoader* loader) : mLoader(loader) {}

     NS_IMETHOD Run() MOZ_OVERRIDE

     {

         mLoader->MainThreadRelease();

         return NS_OK;

     }

 private:

     HRTFDatabaseLoader* mLoader;

 };

 void HRTFDatabaseLoader::ProxyRelease()

 {

     nsCOMPtr<nsIThread> mainThread = do_GetMainThread();

     if (MOZ_LIKELY(mainThread)) {

         nsRefPtr<ProxyReleaseEvent> event = new ProxyReleaseEvent(this);

         DebugOnly<nsresult> rv =

             mainThread->Dispatch(event, NS_DISPATCH_NORMAL);

         MOZ_ASSERT(NS_SUCCEEDED(rv), "Failed to dispatch release event");

     } else {

         // Should be in XPCOM shutdown.

         MOZ_ASSERT(NS_IsMainThread(),

                    "Main thread is not available for dispatch.");

         MainThreadRelease();

     }

 }

 void HRTFDatabaseLoader::MainThreadRelease()

 {

     MOZ_ASSERT(NS_IsMainThread());

     int count = --m_refCnt;

     MOZ_ASSERT(count >= 0, "extra release");

     NS_LOG_RELEASE(this, count, "HRTFDatabaseLoader");

     if (count == 0) {

         // It is safe to delete here as the first reference can only be added

         // on this (main) thread.

         delete this;

     }

 }

 // Asynchronously load the database in this thread.

 static void databaseLoaderEntry(void* threadData)

 {

     PR_SetCurrentThreadName("HRTFDatabaseLdr");

     HRTFDatabaseLoader* loader = reinterpret_cast<HRTFDatabaseLoader*>(threadData);

     MOZ_ASSERT(loader);

     loader->load();

 }

 void HRTFDatabaseLoader::load()

 {

     MOZ_ASSERT(!NS_IsMainThread());

     MOZ_ASSERT(!m_hrtfDatabase.get(), "Called twice");

     // Load the default HRTF database.

     m_hrtfDatabase = HRTFDatabase::create(m_databaseSampleRate);

     // Notifies the main thread of completion.  See loadAsynchronously().

     Release();

 }

 void HRTFDatabaseLoader::loadAsynchronously()

 {

     MOZ_ASSERT(NS_IsMainThread());

     MOZ_ASSERT(m_refCnt, "Must not be called before a reference is added");

     // Add a reference so that the destructor won't run and wait for the

     // loader thread, until load() has completed.

     AddRef();

     MutexAutoLock locker(m_threadLock);

     MOZ_ASSERT(!m_hrtfDatabase.get() && !m_databaseLoaderThread,

                "Called twice");

     // Start the asynchronous database loading process.

     m_databaseLoaderThread =

         PR_CreateThread(PR_USER_THREAD, databaseLoaderEntry, this,

                         PR_PRIORITY_NORMAL, PR_GLOBAL_THREAD,

                         PR_JOINABLE_THREAD, 0);

 }

 bool HRTFDatabaseLoader::isLoaded() const

 {

     return m_hrtfDatabase.get();

 }

 void HRTFDatabaseLoader::waitForLoaderThreadCompletion()

 {

     MutexAutoLock locker(m_threadLock);

     // waitForThreadCompletion() should not be called twice for the same thread.

     if (m_databaseLoaderThread) {

         DebugOnly<PRStatus> status = PR_JoinThread(m_databaseLoaderThread);

         MOZ_ASSERT(status == PR_SUCCESS, "PR_JoinThread failed");

     }

     m_databaseLoaderThread = nullptr;

 }

 PLDHashOperator

 HRTFDatabaseLoader::shutdownEnumFunc(LoaderByRateEntry *entry, void* unused)

 {

     // Ensure the loader thread's reference is removed for leak analysis.

     entry->mLoader->waitForLoaderThreadCompletion();

     return PLDHashOperator::PL_DHASH_NEXT;

 }

 void HRTFDatabaseLoader::shutdown()

 {

     MOZ_ASSERT(NS_IsMainThread());

     if (s_loaderMap) {

         // Set s_loaderMap to nullptr so that the hashtable is not modified on

         // reference release during enumeration.

         nsTHashtable<LoaderByRateEntry>* loaderMap = s_loaderMap;

         s_loaderMap = nullptr;

         loaderMap->EnumerateEntries(shutdownEnumFunc, nullptr);

         delete loaderMap;

     }

 }

 } // namespace WebCore