/****************************************************************************

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** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).

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** This file is part of the QtXmlPatterns module of the Qt Toolkit.

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** No Commercial Usage

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** contained in the Technology Preview License Agreement accompanying

** this package.

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** GNU Lesser General Public License Usage

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** General Public License version 2.1 as published by the Free Software

** Foundation and appearing in the file LICENSE.LGPL included in the

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//

//  W A R N I N G

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

//

// This file is not part of the Qt API.  It exists purely as an

// implementation detail.  This header file may change from version to

// version without notice, or even be removed.

//

// We mean it.

#ifndef Patternist_MaintainingReader_H

#define Patternist_MaintainingReader_H

#include <QSet>

#include <QSourceLocation>

#include <QStack>

#include <QStringList>

#include <QXmlStreamReader>

#include "qxpathhelper_p.h"

#include "qxslttokenlookup_p.h"

class QUrl;

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist

{

    /**

     * @short A structure that lists the optional and required

     * attributes of an element. Used with MaintainingReader.

     *

     * A constant source to misunderstandings is mixing up the order of

     * arguments for functions that takes a local name and a namespace. Be wary

     * of this.

     *

     * @author Frans Englich <frans.englich@nokia.com>

     * @since 4.5

     */

    template<typename TokenLookupClass,

             typename LookupKey = typename TokenLookupClass::NodeName>

    class ElementDescription

    {

    public:

        typedef QHash<LookupKey, ElementDescription<TokenLookupClass, LookupKey> > Hash;

        QSet<typename TokenLookupClass::NodeName> requiredAttributes;

        QSet<typename TokenLookupClass::NodeName> optionalAttributes;

    };

    /**

     * @short Base class for tokenizers that reads XML formats. This is

     * XSLTTokenizer, and the W3C XML Schema parser.

     *

     * MaintainingReader is intended for sub-classing.

     *

     * @tparam TokenLookupClass The name of the class that is generated by

     * QTokenAutomaton and which supplies tokenizing tokens. For XSLTTokenizer,

     * this is XSLTTokenLookup, for instance.

     *

     * @tparam LookupKey The type that is passed to validateElement() and is

     * the key in ElementDescription. For the schema code, where elements have

     * different interpretations depending on context, the lookup key is hence

     * not equal element name.

     *

     * @author Frans Englich <frans.englich@nokia.com>

     * @since 4.5

     */

    template<typename TokenLookupClass,

             typename LookupKey = typename TokenLookupClass::NodeName>

    class MaintainingReader : public QXmlStreamReader

                            , protected TokenLookupClass

    {

    protected:

        MaintainingReader(const typename ElementDescription<TokenLookupClass, LookupKey>::Hash &elementDescriptions,

                          const QSet<typename TokenLookupClass::NodeName> &standardAttributes,

                          const ReportContext::Ptr &context,

                          QIODevice *const queryDevice);

        virtual ~MaintainingReader();

        TokenType readNext();

        /**

         * Returns the name of the current element.

         */

        inline typename TokenLookupClass::NodeName currentElementName() const;

        /**

         * @short Convenience function for calling ReportContext::error().

         */

        void error(const QString &message,

                   const ReportContext::ErrorCode code) const;

        /**

         * @short Convenience function for calling ReportContext::warning().

         */

        void warning(const QString &message) const;

        /**

         * @short Returns the location of the document that MaintainingReader

         * is parsing. Used for error reporting

         */

        virtual QUrl documentURI() const = 0;

        /**

         * @short Returns @c true, if any attribute is allowed on the

         * element currently being validated.

         */

        virtual bool isAnyAttributeAllowed() const = 0;

        /**

         * QXmlStreamReader::isWhitespace() returns true for whitespace that is

         * not expressed as character references, while XSL-T operatates ontop

         * of the XDM, which means we needs to return true for those too.

         *

         * @see <a href="http://www.w3.org/TR/xslt20/#data-model">4 Data Model</a>

         */

        bool isWhitespace() const;

        /**

         * This function is not merged with handleStandardAttributes() because

         * handleStandardAttributes() needs to be called for all elements,

         * while validateElement() only applies to XSL-T elements.

         *

         * @see handleStandardAttributes()

         */

        void validateElement(const LookupKey name) const;

        QXmlStreamAttributes                                                    m_currentAttributes;

        bool                                                                    m_hasHandledStandardAttributes;

        /**

         * This stack mirrors the depth of elements in the parsed document. If

         * no @c xml:space is present on the current element, MaintainingReader

         * simply pushes the current top(). However, it never sets the value

         * depending on @c xml:space's value.

         */

        QStack<bool>                                                            m_stripWhitespace;

        /**

         * @short Returns the value for attribute by name \a name.

         *

         * If it doesn't exist, an error is raised.

         *

         * It is assumed that m_reader's current state is

         * QXmlStreamReader::StartElement.

         */

        QString readAttribute(const QString &localName,

                              const QString &namespaceURI = QString()) const;

        /**

         * @short Returns @c true if the current element has an attribute whose

         * name is @p namespaceURI and local name is @p localName.

         */

        bool hasAttribute(const QString &namespaceURI, const QString &localName) const;

        /**

         * @short Returns @c true if the current element has an attribute whose

         * local name is @p localName and namespace URI is null.

         */

        inline bool hasAttribute(const QString &localName) const;

    private:

        typename TokenLookupClass::NodeName                                     m_currentElementName;

        /**

         * This member is private, see the error() and warning() functions in

         * this class.

         */

        const ReportContext::Ptr                                                m_context;

        /**

         * Returns the current location that QXmlStreamReader has.

         */

        inline QSourceLocation currentLocation() const;

        const typename ElementDescription<TokenLookupClass, LookupKey>::Hash    m_elementDescriptions;

        const QSet<typename TokenLookupClass::NodeName>                         m_standardAttributes;

        Q_DISABLE_COPY(MaintainingReader)

    };

#include "qmaintainingreader.cpp"

}

QT_END_NAMESPACE

QT_END_HEADER

#endif