/*

 * Copyright (C) 2010 Apple 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.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE INC. 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 INC. 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 "WorkQueue.h"

#include <process.h>

#include <wtf/Threading.h>

void WorkQueue::registerHandle(HANDLE handle, PassOwnPtr<WorkItem> item)

{

    // Add the item.

    {

        MutexLocker locker(m_handlesLock);

        m_handles.set(handle, item.leakPtr());

    }

    // Set the work event.

    ::SetEvent(m_performWorkEvent);

}

void* WorkQueue::workQueueThreadBody(void *context)

{

    static_cast<WorkQueue*>(context)->workQueueThreadBody();

    return 0;

}

void WorkQueue::workQueueThreadBody()

{

    while (true) {

        Vector<HANDLE> handles;

        {

            // Copy the handles to our handles vector.

            MutexLocker locker(m_handlesLock);

            copyKeysToVector(m_handles, handles);

        }

        // Add the "perform work" event handle.

        handles.append(m_performWorkEvent);

        // Now we wait.

        DWORD result = ::WaitForMultipleObjects(handles.size(), handles.data(), FALSE, INFINITE);

        if (result == handles.size() - 1)

            performWork();

        else {

            // FIXME: If we ever decide to support unregistering handles we would need to copy the hash map.

            WorkItem* workItem;

            HANDLE handle = handles[result];

            {

                MutexLocker locker(m_handlesLock);

                workItem = m_handles.get(handle);

            }

            // Execute the work item.

            workItem->execute();

        }

        // Check if this queue is invalid.

        {

            MutexLocker locker(m_isValidMutex);

            if (!m_isValid)

                break;

        }

    }

}

void WorkQueue::platformInitialize(const char* name)

{

    // Create our event.

    m_performWorkEvent = ::CreateEvent(0, false, false, 0);

    m_workQueueThread = createThread(&WorkQueue::workQueueThreadBody, this, name);

}

void WorkQueue::platformInvalidate()

{

    ::CloseHandle(m_performWorkEvent);

    // FIXME: Stop the thread and do other cleanup.

}

void WorkQueue::scheduleWork(PassOwnPtr<WorkItem> item)

{

    MutexLocker locker(m_workItemQueueLock);

    m_workItemQueue.append(item.leakPtr());

    // Set the work event.

    ::SetEvent(m_performWorkEvent);

}

void WorkQueue::performWork()

{

    Vector<WorkItem*> workItemQueue;

    {

        MutexLocker locker(m_workItemQueueLock);

        m_workItemQueue.swap(workItemQueue);

    }

    for (size_t i = 0; i < workItemQueue.size(); ++i) {

        OwnPtr<WorkItem> item(workItemQueue[i]);

        MutexLocker locker(m_isValidMutex);

        if (m_isValid)

            item->execute();

    }

}