/*

 * 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"

#include "GeckoProfiler.h"

#include "nsThreadUtils.h"

using namespace mozilla;

namespace WebCore {

// Singleton

nsTHashtable<HRTFDatabaseLoader::LoaderByRateEntry>*

    HRTFDatabaseLoader::s_loaderMap = nullptr;

size_t HRTFDatabaseLoader::sizeOfLoaders(mozilla::MallocSizeOf aMallocSizeOf)

{

    return s_loaderMap ? s_loaderMap->SizeOfIncludingThis(aMallocSizeOf) : 0;

}

already_AddRefed<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.forget();

    }

    loader = new HRTFDatabaseLoader(sampleRate);

    entry->mLoader = loader;

    loader->loadAsynchronously();

    return loader.forget();

}

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 final : public Runnable {

public:

  explicit ProxyReleaseEvent(HRTFDatabaseLoader* loader)

    : mozilla::Runnable("WebCore::HRTFDatabaseLoader::ProxyReleaseEvent")

    , mLoader(loader)

  {

  }

  NS_IMETHOD Run() override

  {

    mLoader->MainThreadRelease();

    return NS_OK;

    }

private:

    // Ownership transferred by ProxyRelease

    HRTFDatabaseLoader* MOZ_OWNING_REF mLoader;

};

void HRTFDatabaseLoader::ProxyRelease()

{

    nsCOMPtr<nsIEventTarget> mainTarget = GetMainThreadEventTarget();

    if (MOZ_LIKELY(mainTarget)) {

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

        DebugOnly<nsresult> rv =

            mainTarget->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)

{

    AUTO_PROFILER_REGISTER_THREAD("HRTFDatabaseLdr");

    NS_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;

}

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;

        for (auto iter = loaderMap->Iter(); !iter.Done(); iter.Next()) {

          iter.Get()->mLoader->waitForLoaderThreadCompletion();

        }

        delete loaderMap;

    }

}

} // namespace WebCore