/*

 * 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.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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

 * 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 "HTMLParserScheduler.h"

#include "FrameView.h" // Only for isLayoutTimerActive

#include "HTMLDocumentParser.h"

#include "Document.h"

// defaultParserChunkSize is used to define how many tokens the parser will

// process before checking against parserTimeLimit and possibly yielding.

// This is a performance optimization to prevent checking after every token.

static const int defaultParserChunkSize = 4096;

// defaultParserTimeLimit is the seconds the parser will run in one write() call

// before yielding.  Inline <script> execution can cause it to excede the limit.

// FIXME: We would like this value to be 0.2.

static const double defaultParserTimeLimit = 0.500;

namespace WebCore {

static double parserTimeLimit(Page* page)

{

    // We're using the poorly named customHTMLTokenizerTimeDelay setting.

    if (page && page->hasCustomHTMLTokenizerTimeDelay())

        return page->customHTMLTokenizerTimeDelay();

    return defaultParserTimeLimit;

}

static int parserChunkSize(Page* page)

{

    // FIXME: We may need to divide the value from customHTMLTokenizerChunkSize

    // by some constant to translate from the "character" based behavior of the

    // old LegacyHTMLDocumentParser to the token-based behavior of this parser.

    if (page && page->hasCustomHTMLTokenizerChunkSize())

        return page->customHTMLTokenizerChunkSize();

    return defaultParserChunkSize;

}

HTMLParserScheduler::HTMLParserScheduler(HTMLDocumentParser* parser)

    : m_parser(parser)

    , m_parserTimeLimit(parserTimeLimit(m_parser->document()->page()))

    , m_parserChunkSize(parserChunkSize(m_parser->document()->page()))

    , m_continueNextChunkTimer(this, &HTMLParserScheduler::continueNextChunkTimerFired)

{

}

HTMLParserScheduler::~HTMLParserScheduler()

{

    m_continueNextChunkTimer.stop();

}

// FIXME: This belongs on Document.

static bool isLayoutTimerActive(Document* doc)

{

    ASSERT(doc);

    return doc->view() && doc->view()->layoutPending() && !doc->minimumLayoutDelay();

}

void HTMLParserScheduler::continueNextChunkTimerFired(Timer<HTMLParserScheduler>* timer)

{

    ASSERT_UNUSED(timer, timer == &m_continueNextChunkTimer);

    // FIXME: The timer class should handle timer priorities instead of this code.

    // If a layout is scheduled, wait again to let the layout timer run first.

    if (isLayoutTimerActive(m_parser->document())) {

        m_continueNextChunkTimer.startOneShot(0);

        return;

    }

    m_parser->resumeParsingAfterYield();

}

}