/*

 * Copyright (C) 2007 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. 

 * 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 "config.h"

#include "Threading.h"

#include "Logging.h"

#include "Page.h"

#include <windows.h>

namespace WebCore {

static HWND threadingWindowHandle = 0;

static UINT threadingFiredMessage = 0;

const LPCWSTR kThreadingWindowClassName = L"ThreadingWindowClass";

static bool processingCustomThreadingMessage = false;

Mutex functionQueueMutex;

Vector<void(*)()> functionQueue;

static void callFunctionsOnMainThread()

{

    Vector<void(*)()> queueCopy;

    {

        MutexLocker locker(functionQueueMutex);

        queueCopy.swap(functionQueue);

    }

    LOG(Threading, "Calling %u functions on the main thread", queueCopy.size());

    for (unsigned i = 0; i < queueCopy.size(); ++i)

        queueCopy[i]();

}

LRESULT CALLBACK ThreadingWindowWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)

{

    if (message == threadingFiredMessage) {

        processingCustomThreadingMessage = true;

        callFunctionsOnMainThread();

        processingCustomThreadingMessage = false;

    } else

        return DefWindowProc(hWnd, message, wParam, lParam);

    return 0;

}

void initializeThreading()

{

    if (threadingWindowHandle)

        return;

    WNDCLASSEX wcex;

    memset(&wcex, 0, sizeof(WNDCLASSEX));

    wcex.cbSize = sizeof(WNDCLASSEX);

    wcex.lpfnWndProc    = ThreadingWindowWndProc;

    wcex.hInstance      = Page::instanceHandle();

    wcex.lpszClassName  = kThreadingWindowClassName;

    RegisterClassEx(&wcex);

    threadingWindowHandle = CreateWindow(kThreadingWindowClassName, 0, 0,

       CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, HWND_MESSAGE, 0, Page::instanceHandle(), 0);

    threadingFiredMessage = RegisterWindowMessage(L"com.apple.WebKit.MainThreadFired");

}

void callOnMainThread(void(*function)())

{

    ASSERT(function);

    ASSERT(threadingWindowHandle);

    if (processingCustomThreadingMessage)

        LOG(Threading, "callOnMainThread() called recursively.  Beware of nested PostMessage()s");

    {

        MutexLocker locker(functionQueueMutex);

        functionQueue.append(function);

    }

    PostMessage(threadingWindowHandle, threadingFiredMessage, 0, 0);

}

} // namespace WebCore