/*
 * Copyright (C) 2000 Peter Kelly (pmk@post.com)
 * Copyright (C) 2005, 2006, 2008 Apple Inc. All rights reserved.
 * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
 * Copyright (C) 2007 Samuel Weinig (sam@webkit.org)
 * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
 * Copyright (C) 2008 Holger Hans Peter Freyther
 * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "config.h"
#include "XMLDocumentParser.h"

#include "CDATASection.h"
#include "CachedScript.h"
#include "Comment.h"
#include "CachedResourceLoader.h"
#include "Document.h"
#include "DocumentFragment.h"
#include "DocumentType.h"
#include "ExceptionCodePlaceholder.h"
#include "Frame.h"
#include "FrameLoader.h"
#include "FrameView.h"
#include "HTMLEntityParser.h"
#include "HTMLHtmlElement.h"
#include "HTMLLinkElement.h"
#include "HTMLNames.h"
#include "HTMLStyleElement.h"
#include "ProcessingInstruction.h"
#include "ResourceError.h"
#include "ResourceHandle.h"
#include "ResourceRequest.h"
#include "ResourceResponse.h"
#include "ScriptableDocumentParser.h"
#include "ScriptElement.h"
#include "ScriptSourceCode.h"
#include "ScriptValue.h"
#include "TextResourceDecoder.h"
#include "TransformSource.h"
#include "XMLNSNames.h"
#include <QDebug>
#include <wtf/StringExtras.h>
#include <wtf/Threading.h>
#include <wtf/Vector.h>
#include <wtf/text/CString.h>

using namespace std;

namespace WebCore {

static inline void setAttributes(Element* element, Vector<Attribute>& attributeVector, ParserContentPolicy parserContentPolicy)
{
    if (!scriptingContentIsAllowed(parserContentPolicy))
        element->stripScriptingAttributes(attributeVector);
    element->parserSetAttributes(attributeVector);
}

class EntityResolver : public QXmlStreamEntityResolver {
    virtual QString resolveUndeclaredEntity(const QString &name);
};

static QString decodeNamedEntity(const QString& entityName)
{
    UChar utf16DecodedEntity[4];
    size_t numberOfCodePoints = decodeNamedEntityToUCharArray(entityName.toUtf8().constData(), utf16DecodedEntity);
    return QString(reinterpret_cast<const QChar*>(utf16DecodedEntity), numberOfCodePoints);
}

QString EntityResolver::resolveUndeclaredEntity(const QString &name)
{
    return decodeNamedEntity(name);
}

// --------------------------------

bool XMLDocumentParser::supportsXMLVersion(const String& version)
{
    return version == "1.0";
}

XMLDocumentParser::XMLDocumentParser(Document* document, FrameView* frameView)
    : ScriptableDocumentParser(document)
    , m_view(frameView)
    , m_wroteText(false)
    , m_currentNode(document)
    , m_sawError(false)
    , m_sawCSS(false)
    , m_sawXSLTransform(false)
    , m_sawFirstElement(false)
    , m_isXHTMLDocument(false)
    , m_parserPaused(false)
    , m_requestingScript(false)
    , m_finishCalled(false)
    , m_xmlErrors(document)
    , m_pendingScript(0)
    , m_scriptStartPosition(TextPosition::belowRangePosition())
    , m_parsingFragment(false)
{
    m_stream.setEntityResolver(new EntityResolver);
}

XMLDocumentParser::XMLDocumentParser(DocumentFragment* fragment, Element* parentElement, ParserContentPolicy parserContentPolicy)
    : ScriptableDocumentParser(fragment->document(), parserContentPolicy)
    , m_view(0)
    , m_wroteText(false)
    , m_currentNode(fragment)
    , m_sawError(false)
    , m_sawCSS(false)
    , m_sawXSLTransform(false)
    , m_sawFirstElement(false)
    , m_isXHTMLDocument(false)
    , m_parserPaused(false)
    , m_requestingScript(false)
    , m_finishCalled(false)
    , m_xmlErrors(fragment->document())
    , m_pendingScript(0)
    , m_scriptStartPosition(TextPosition::belowRangePosition())
    , m_parsingFragment(true)
{
    fragment->ref();

    // Add namespaces based on the parent node
    Vector<Element*> elemStack;
    while (parentElement) {
        elemStack.append(parentElement);

        Node* n = parentElement->parentNode();
        if (!n || !n->isElementNode())
            break;
        parentElement = toElement(n);
    }

    if (elemStack.isEmpty())
        return;

    QXmlStreamNamespaceDeclarations namespaces;
    for (Element* element = elemStack.last(); !elemStack.isEmpty(); elemStack.removeLast()) {
        element->synchronizeAllAttributes();
        if (const ElementData* attrs = element->elementData()) {
            for (unsigned i = 0; i < attrs->length(); i++) {
                const Attribute* attr = attrs->attributeItem(i);
                if (attr->localName() == "xmlns")
                    m_defaultNamespaceURI = attr->value();
                else if (attr->prefix() == "xmlns")
                    namespaces.append(QXmlStreamNamespaceDeclaration(attr->localName(), attr->value()));
            }
        }
    }
    m_stream.addExtraNamespaceDeclarations(namespaces);
    m_stream.setEntityResolver(new EntityResolver);

    // If the parent element is not in document tree, there may be no xmlns attribute; just default to the parent's namespace.
    if (m_defaultNamespaceURI.isNull() && !parentElement->inDocument())
        m_defaultNamespaceURI = parentElement->namespaceURI();
}

XMLDocumentParser::~XMLDocumentParser()
{
    clearCurrentNodeStack();
    if (m_pendingScript)
        m_pendingScript->removeClient(this);
    delete m_stream.entityResolver();
}

void XMLDocumentParser::doWrite(const String& parseString)
{
    m_wroteText = true;

    if (document()->decoder() && document()->decoder()->sawError()) {
        // If the decoder saw an error, report it as fatal (stops parsing)
        handleError(XMLErrors::fatal, "Encoding error", textPosition());
        return;
    }

    QString data(parseString);
    if (!data.isEmpty()) {
        // JavaScript may cause the parser to detach,
        // keep this alive until this function is done.
        RefPtr<XMLDocumentParser> protect(this);

        m_stream.addData(data);
        parse();
    }

    return;
}

void XMLDocumentParser::initializeParserContext(const CString&)
{
    DocumentParser::startParsing();
    m_sawError = false;
    m_sawCSS = false;
    m_sawXSLTransform = false;
    m_sawFirstElement = false;
}

void XMLDocumentParser::doEnd()
{
#if ENABLE(XSLT)
    if (m_sawXSLTransform) {
        document()->setTransformSource(adoptPtr(new TransformSource(m_originalSourceForTransform.toString())));
        document()->setParsing(false); // Make the doc think it's done, so it will apply xsl sheets.
        document()->styleResolverChanged(RecalcStyleImmediately);

        // styleResolverChanged() call can detach the parser and null out its document.
        // In that case, we just bail out.
        if (isDetached())
            return;

        document()->setParsing(true);
        DocumentParser::stopParsing();
    }
#endif

    if (m_stream.error() == QXmlStreamReader::PrematureEndOfDocumentError
        || (m_wroteText && !m_sawFirstElement && !m_sawXSLTransform && !m_sawError))
        handleError(XMLErrors::fatal, qPrintable(m_stream.errorString()), textPosition());
}

OrdinalNumber XMLDocumentParser::lineNumber() const
{
    return OrdinalNumber::fromOneBasedInt(m_stream.lineNumber());
}

OrdinalNumber XMLDocumentParser::columnNumber() const
{
    return OrdinalNumber::fromOneBasedInt(m_stream.columnNumber());
}

TextPosition XMLDocumentParser::textPosition() const
{
    return TextPosition(lineNumber(), columnNumber());
}

void XMLDocumentParser::stopParsing()
{
    ScriptableDocumentParser::stopParsing();
}

void XMLDocumentParser::resumeParsing()
{
    ASSERT(m_parserPaused);

    m_parserPaused = false;

    // First, execute any pending callbacks
    parse();
    if (m_parserPaused)
        return;

    // Then, write any pending data
    SegmentedString rest = m_pendingSrc;
    m_pendingSrc.clear();
    append(rest.toString().impl());

    // Finally, if finish() has been called and append() didn't result
    // in any further callbacks being queued, call end()
    if (m_finishCalled && !m_parserPaused && !m_pendingScript)
        end();
}

bool XMLDocumentParser::appendFragmentSource(const String& source)
{
    ASSERT(!m_sawFirstElement);
    append(String("<qxmlstreamdummyelement>").impl());
    append(source.impl());
    append(String("</qxmlstreamdummyelement>").impl());
    return !hasError();
}

// --------------------------------

struct AttributeParseState {
    HashMap<String, String> attributes;
    bool gotAttributes;
};

static void attributesStartElementNsHandler(AttributeParseState* state, const QXmlStreamAttributes& attrs)
{
    if (attrs.count() <= 0)
        return;

    state->gotAttributes = true;

    for (int i = 0; i < attrs.count(); i++) {
        const QXmlStreamAttribute& attr = attrs[i];
        String attrLocalName = attr.name();
        String attrValue     = attr.value();
        String attrURI       = attr.namespaceUri();
        String attrQName     = attr.qualifiedName();
        state->attributes.set(attrQName, attrValue);
    }
}

HashMap<String, String> parseAttributes(const String& string, bool& attrsOK)
{
    AttributeParseState state;
    state.gotAttributes = false;

    QXmlStreamReader stream;
    QString dummy = QString(QLatin1String("<?xml version=\"1.0\"?><attrs %1 />")).arg(string);
    stream.addData(dummy);
    while (!stream.atEnd()) {
        stream.readNext();
        if (stream.isStartElement()) {
            attributesStartElementNsHandler(&state, stream.attributes());
        }
    }
    attrsOK = state.gotAttributes;
    return state.attributes;
}

static inline String prefixFromQName(const QString& qName)
{
    const int offset = qName.indexOf(QLatin1Char(':'));
    if (offset <= 0)
        return String();
    else
        return qName.left(offset);
}

static inline void handleNamespaceAttributes(Vector<Attribute>& prefixedAttributes, const QXmlStreamNamespaceDeclarations &ns, ExceptionCode& ec)
{
    for (int i = 0; i < ns.count(); ++i) {
        const QXmlStreamNamespaceDeclaration &decl = ns[i];
        String namespaceURI = decl.namespaceUri();
        String namespaceQName = decl.prefix().isEmpty() ? String("xmlns") : String("xmlns:");
        namespaceQName.append(decl.prefix());

        QualifiedName parsedName = anyName;
        if (!Element::parseAttributeName(parsedName, XMLNSNames::xmlnsNamespaceURI, namespaceQName, ec))
            return;

        prefixedAttributes.append(Attribute(parsedName, namespaceURI));
    }
}

static inline void handleElementAttributes(Vector<Attribute>& prefixedAttributes, const QXmlStreamAttributes &attrs, ExceptionCode& ec)
{
    for (int i = 0; i < attrs.count(); ++i) {
        const QXmlStreamAttribute &attr = attrs[i];
        String attrLocalName = attr.name();
        String attrValue     = attr.value();
        String attrURI       = attr.namespaceUri().isEmpty() ? String() : String(attr.namespaceUri());
        String attrQName     = attr.qualifiedName();

        QualifiedName parsedName = anyName;
        if (!Element::parseAttributeName(parsedName, attrURI, attrQName, ec))
            return;

        prefixedAttributes.append(Attribute(parsedName, attrValue));
    }
}

void XMLDocumentParser::parse()
{
    while (!isStopped() && !m_parserPaused && !m_stream.atEnd()) {
        m_stream.readNext();
        switch (m_stream.tokenType()) {
        case QXmlStreamReader::StartDocument:
            startDocument();
            break;
        case QXmlStreamReader::EndDocument:
            endDocument();
            break;
        case QXmlStreamReader::StartElement:
            parseStartElement();
            break;
        case QXmlStreamReader::EndElement:
            parseEndElement();
            break;
        case QXmlStreamReader::Characters: {
            if (m_stream.isCDATA()) {
                //cdata
                parseCdata();
            } else {
                //characters
                parseCharacters();
            }
            break;
        }
        case QXmlStreamReader::Comment:
            parseComment();
            break;
        case QXmlStreamReader::DTD:
            //qDebug()<<"------------- DTD";
            parseDtd();
            break;
        case QXmlStreamReader::EntityReference: {
            //qDebug()<<"---------- ENTITY = "<<m_stream.name().toString()
            //        <<", t = "<<m_stream.text().toString();
            if (isXHTMLDocument()) {
                QString entity = m_stream.name().toString();
                if (!m_leafTextNode)
                    enterText();
                // qDebug()<<" ------- adding entity "<<str;
                m_leafTextNode->appendData(decodeNamedEntity(entity), IGNORE_EXCEPTION);
            }
            break;
        }
        case QXmlStreamReader::ProcessingInstruction:
            parseProcessingInstruction();
            break;
        default: {
            if (m_stream.error() != QXmlStreamReader::PrematureEndOfDocumentError) {
                XMLErrors::ErrorType type = (m_stream.error() == QXmlStreamReader::NotWellFormedError) ?
                                 XMLErrors::fatal : XMLErrors::warning;
                handleError(type, qPrintable(m_stream.errorString()), textPosition());
            }
            break;
        }
        }
    }
}

void XMLDocumentParser::startDocument()
{
    initializeParserContext();

    if (!m_parsingFragment) {
        document()->setXMLStandalone(m_stream.isStandaloneDocument(), IGNORE_EXCEPTION);

        QStringRef version = m_stream.documentVersion();
        if (!version.isEmpty())
            document()->setXMLVersion(version, IGNORE_EXCEPTION);
        QStringRef encoding = m_stream.documentEncoding();
        if (!encoding.isEmpty())
            document()->setXMLEncoding(encoding);
        document()->setHasXMLDeclaration(!version.isEmpty());
    }
}

void XMLDocumentParser::parseStartElement()
{
    if (!m_sawFirstElement && m_parsingFragment) {
        // skip dummy element for fragments
        m_sawFirstElement = true;
        return;
    }

    exitText();

    String localName = m_stream.name();
    String uri       = m_stream.namespaceUri();
    String prefix    = prefixFromQName(m_stream.qualifiedName().toString());

    if (m_parsingFragment && uri.isNull()) {
        Q_ASSERT(prefix.isNull());
        uri = m_defaultNamespaceURI;
    }

    QualifiedName qName(prefix, localName, uri);
    RefPtr<Element> newElement = document()->createElement(qName, true);
    if (!newElement) {
        stopParsing();
        return;
    }

    bool isFirstElement = !m_sawFirstElement;
    m_sawFirstElement = true;

    Vector<Attribute> prefixedAttributes;
    ExceptionCode ec = 0;
    handleNamespaceAttributes(prefixedAttributes, m_stream.namespaceDeclarations(), ec);
    if (ec) {
        setAttributes(newElement.get(), prefixedAttributes, parserContentPolicy());
        stopParsing();
        return;
    }

    handleElementAttributes(prefixedAttributes, m_stream.attributes(), ec);
    setAttributes(newElement.get(), prefixedAttributes, parserContentPolicy());
    if (ec) {
        stopParsing();
        return;
    }

    ScriptElement* scriptElement = toScriptElementIfPossible(newElement.get());
    if (scriptElement)
        m_scriptStartPosition = textPosition();

    m_currentNode->parserAppendChild(newElement.get());

    pushCurrentNode(newElement.get());
    if (m_view && !newElement->attached())
        newElement->attach();

    if (newElement->hasTagName(HTMLNames::htmlTag))
        static_cast<HTMLHtmlElement*>(newElement.get())->insertedByParser();

    if (isFirstElement && document()->frame())
        document()->frame()->loader()->dispatchDocumentElementAvailable();
}

void XMLDocumentParser::parseEndElement()
{
    exitText();

    RefPtr<ContainerNode> n = m_currentNode;
    n->finishParsingChildren();

    if (!scriptingContentIsAllowed(parserContentPolicy()) && n->isElementNode() && toScriptElementIfPossible(toElement(n.get()))) {
        popCurrentNode();
        n->remove(IGNORE_EXCEPTION);
        return;
    }

    if (!n->isElementNode() || !m_view) {
        if (!m_currentNodeStack.isEmpty())
            popCurrentNode();
        return;
    }

    Element* element = toElement(n.get());

    // The element's parent may have already been removed from document.
    // Parsing continues in this case, but scripts aren't executed.
    if (!element->inDocument()) {
        popCurrentNode();
        return;
    }

    ScriptElement* scriptElement = toScriptElementIfPossible(element);
    if (!scriptElement) {
        popCurrentNode();
        return;
    }

    // don't load external scripts for standalone documents (for now)
    ASSERT(!m_pendingScript);
    m_requestingScript = true;

    if (scriptElement->prepareScript(m_scriptStartPosition, ScriptElement::AllowLegacyTypeInTypeAttribute)) {
        if (scriptElement->readyToBeParserExecuted())
            scriptElement->executeScript(ScriptSourceCode(scriptElement->scriptContent(), document()->url(), m_scriptStartPosition));
        else if (scriptElement->willBeParserExecuted()) {
            m_pendingScript = scriptElement->cachedScript();
            m_scriptElement = element;
            m_pendingScript->addClient(this);

            // m_pendingScript will be 0 if script was already loaded and addClient() executed it.
            if (m_pendingScript)
                pauseParsing();
        } else
            m_scriptElement = 0;
    }
    m_requestingScript = false;
    popCurrentNode();
}

void XMLDocumentParser::parseCharacters()
{
    if (!m_leafTextNode)
        enterText();
    m_leafTextNode->appendData(m_stream.text(), IGNORE_EXCEPTION);
}

void XMLDocumentParser::parseProcessingInstruction()
{
    exitText();

    // ### handle exceptions
    int exception = 0;
    RefPtr<ProcessingInstruction> pi = document()->createProcessingInstruction(
        m_stream.processingInstructionTarget(),
        m_stream.processingInstructionData(), exception);
    if (exception)
        return;

    pi->setCreatedByParser(true);

    m_currentNode->parserAppendChild(pi.get());
    if (m_view && !pi->attached())
        pi->attach();

    pi->finishParsingChildren();

    if (pi->isCSS())
        m_sawCSS = true;
#if ENABLE(XSLT)
    m_sawXSLTransform = !m_sawFirstElement && pi->isXSL();
    if (m_sawXSLTransform && !document()->transformSourceDocument())
        stopParsing();
#endif
}

void XMLDocumentParser::parseCdata()
{
    exitText();

    RefPtr<CDATASection> newNode = CDATASection::create(document(), m_stream.text());

    m_currentNode->parserAppendChild(newNode.get());
    if (m_view && !newNode->attached())
        newNode->attach();
}

void XMLDocumentParser::parseComment()
{
    exitText();

    RefPtr<Comment> newNode = Comment::create(document(), m_stream.text());

    m_currentNode->parserAppendChild(newNode.get());
    if (m_view && !newNode->attached())
        newNode->attach();
}

void XMLDocumentParser::endDocument()
{
}

bool XMLDocumentParser::hasError() const
{
    return m_stream.hasError();
}

void XMLDocumentParser::parseDtd()
{
    QStringRef name = m_stream.dtdName();
    QStringRef publicId = m_stream.dtdPublicId();
    QStringRef systemId = m_stream.dtdSystemId();

    //qDebug() << dtd << name << publicId << systemId;
    if ((publicId == QLatin1String("-//W3C//DTD XHTML 1.0 Transitional//EN"))
        || (publicId == QLatin1String("-//W3C//DTD XHTML 1.1//EN"))
        || (publicId == QLatin1String("-//W3C//DTD XHTML 1.0 Strict//EN"))
        || (publicId == QLatin1String("-//W3C//DTD XHTML 1.0 Frameset//EN"))
        || (publicId == QLatin1String("-//W3C//DTD XHTML Basic 1.0//EN"))
        || (publicId == QLatin1String("-//W3C//DTD XHTML 1.1 plus MathML 2.0//EN"))
        || (publicId == QLatin1String("-//W3C//DTD XHTML 1.1 plus MathML 2.0 plus SVG 1.1//EN"))
        || (publicId == QLatin1String("-//WAPFORUM//DTD XHTML Mobile 1.0//EN"))
        || (publicId == QLatin1String("-//WAPFORUM//DTD XHTML Mobile 1.1//EN"))
        || (publicId == QLatin1String("-//WAPFORUM//DTD XHTML Mobile 1.2//EN"))
       )
        setIsXHTMLDocument(true); // controls if we replace entities or not.
    if (!m_parsingFragment)
        document()->parserAppendChild(DocumentType::create(document(), name, publicId, systemId));

}
}