/*

 * Copyright (C) 2008 Apple Inc. All Rights Reserved.

 * Copyright (C) 2009 Torch Mobile, Inc. http://www.torchmobile.com/

 * 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 "CSSPreloadScanner.h"

#include "CSSHelper.h"

#include "CachedCSSStyleSheet.h"

#include "DocLoader.h"

#include "Document.h"

#include "HTMLToken.h"

namespace WebCore {

static inline bool isWhitespace(UChar c)

{

    return c == ' ' || c == '\n' || c == '\r' || c == '\t';

}

CSSPreloadScanner::CSSPreloadScanner(Document* document)

    : m_document(document)

{

    reset();

}

void CSSPreloadScanner::reset()

{

    m_state = Initial;

    m_rule.clear();

    m_ruleValue.clear();

}

void CSSPreloadScanner::scan(const HTMLToken& token, bool scanningBody)

{

    m_scanningBody = scanningBody;

    const HTMLToken::DataVector& characters = token.characters();

    for (HTMLToken::DataVector::const_iterator iter = characters.begin();

         iter != characters.end(); ++iter) {

        tokenize(*iter);

    }

}

inline void CSSPreloadScanner::tokenize(UChar c)

{

    // We are just interested in @import rules, no need for real tokenization here

    // Searching for other types of resources is probably low payoff.

    switch (m_state) {

    case Initial:

        if (c == '@')

            m_state = RuleStart;

        else if (c == '/')

            m_state = MaybeComment;

        break;

    case MaybeComment:

        if (c == '*')

            m_state = Comment;

        else

            m_state = Initial;

        break;

    case Comment:

        if (c == '*')

            m_state = MaybeCommentEnd;

        break;

    case MaybeCommentEnd:

        if (c == '/')

            m_state = Initial;

        else if (c == '*')

            ;

        else

            m_state = Comment;

        break;

    case RuleStart:

        if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z')) {

            m_rule.clear();

            m_ruleValue.clear();

            m_rule.append(c);

            m_state = Rule;

        } else

            m_state = Initial;

        break;

    case Rule:

        if (isWhitespace(c))

            m_state = AfterRule;

        else if (c == ';')

            m_state = Initial;

        else

            m_rule.append(c);

        break;

    case AfterRule:

        if (isWhitespace(c))

            ;

        else if (c == ';')

            m_state = Initial;

        else {

            m_state = RuleValue;

            m_ruleValue.append(c);

        }

        break;

    case RuleValue:

        if (isWhitespace(c))

            m_state = AfterRuleValue;

        else if (c == ';') {

            emitRule();

            m_state = Initial;

        } else 

            m_ruleValue.append(c);

        break;

    case AfterRuleValue:

        if (isWhitespace(c))

            ;

        else if (c == ';') {

            emitRule();

            m_state = Initial;

        } else {

            // FIXME: media rules

            m_state = Initial;

        }

        break;

    }

}

void CSSPreloadScanner::emitRule()

{

    String rule(m_rule.data(), m_rule.size());

    if (equalIgnoringCase(rule, "import") && !m_ruleValue.isEmpty()) {

        String value(m_ruleValue.data(), m_ruleValue.size());

        String url = deprecatedParseURL(value);

        if (!url.isEmpty())

            m_document->docLoader()->preload(CachedResource::CSSStyleSheet, url, String(), m_scanningBody);

    }

    m_rule.clear();

    m_ruleValue.clear();

}

}