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

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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_XQueryTokenizer_H

#define Patternist_XQueryTokenizer_H

#include <QHash>

#include <QSet>

#include <QStack>

#include <QString>

#include <QUrl>

#include "qtokenizer_p.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist

{

    struct TokenMap;

    /**

     * @short A hand-written tokenizer which tokenizes XQuery 1.0 & XPath 2.0,

     * and delivers tokens to the Bison generated parser.

     *

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

     */

    class XQueryTokenizer : public Tokenizer

    {

    public:

        /**

         * Tokenizer states. Organized alphabetically.

         */

        enum State

        {

            AfterAxisSeparator,

            AposAttributeContent,

            Axis,

            Default,

            ElementContent,

            EndTag,

            ItemType,

            KindTest,

            KindTestForPI,

            NamespaceDecl,

            NamespaceKeyword,

            OccurrenceIndicator,

            Operator,

            Pragma,

            PragmaContent,

            ProcessingInstructionContent,

            ProcessingInstructionName,

            QuotAttributeContent,

            StartTag,

            VarName,

            XMLComment,

            XMLSpaceDecl,

            XQueryVersion

        };

        XQueryTokenizer(const QString &query,

                        const QUrl &location,

                        const State startingState = Default);

        virtual Token nextToken(YYLTYPE *const sourceLocator);

        virtual int commenceScanOnly();

        virtual void resumeTokenizationFrom(const int position);

        /**

         * Does nothing.

         */

        virtual void setParserContext(const ParserContext::Ptr &parseInfo);

    private:

        /**

         * Returns the character corresponding to the builtin reference @p

         * reference. For instance, passing @c gt will give you '>' in return.

         *

         * If @p reference is an invalid character reference, a null QChar is

         * returned.

         *

         * @see QChar::isNull()

         */

        QChar charForReference(const QString &reference);

        inline Token tokenAndChangeState(const TokenType code,

                                         const State state,

                                         const int advance = 1);

        inline Token tokenAndChangeState(const TokenType code,

                                         const QString &value,

                                         const State state);

        inline Token tokenAndAdvance(const TokenType code,

                                     const int advance = 1);

        QString tokenizeCharacterReference();

        inline Token tokenizeStringLiteral();

        inline Token tokenizeNumberLiteral();

        /**

         * @returns the character @p length characters from the current

         * position.

         */

        inline char peekAhead(const int length = 1) const;

        /**

         * @returns whether the stream, starting from @p offset from the

         * current position, matches @p chs. The length of @p chs is @p len.

         */

        inline bool aheadEquals(const char *const chs,

                                const int len,

                                const int offset = 1) const;

        inline Token tokenizeNCName();

        static inline bool isOperatorKeyword(const TokenType);

        static inline bool isDigit(const char ch);

        static inline Token error();

        inline TokenType consumeWhitespace();

        /**

         * @short Returns the character at the current position, converted to

         * @c ASCII.

         *

         * Equivalent to calling:

         *

         * @code

         * current().toAscii();

         * @endcode

         */

        inline char peekCurrent() const;

        /**

         * Disregarding encoding conversion, equivalent to calling:

         *

         * @code

         * peekAhead(0);

         * @endcode

         */

        inline const QChar current() const;

        /**

         * @p hadWhitespace is always set to a proper value.

         *

         * @returns the length of whitespace scanned before reaching "::", or

         * -1 if something else was found.

         */

        int peekForColonColon() const;

        static inline bool isNCNameStart(const QChar ch);

        static inline bool isNCNameBody(const QChar ch);

        static inline const TokenMap *lookupKeyword(const QString &keyword);

        inline void popState();

        inline void pushState(const State state);

        inline State state() const;

        inline void setState(const State s);

        static bool isTypeToken(const TokenType t);

        inline Token tokenizeNCNameOrQName();

        /**

         * Advances m_pos until content is encountered.

         *

         * Returned is the length stretching from m_pos when starting, until

         * @p content is encountered. @p content is not included in the length.

         */

        int scanUntil(const char *const content);

        /**

         * Same as calling:

         * @code

         * pushState(currentState());

         * @endcode

         */

        inline void pushState();

        /**

         * Consumes only whitespace, in the traditional sense. The function exits

         * if non-whitespace is encountered, such as the start of a comment.

         *

         * @returns @c true if the end was reached, otherwise @c false

         */

        inline bool consumeRawWhitespace();

        /**

         * @short Parses comments: <tt>(: comment content :)</tt>. It recurses for

         * parsing nested comments.

         *

         * It is assumed that the start token for the comment, "(:", has

         * already been parsed.

         *

         * Typically, don't call this function, but ignoreWhitespace().

         *

         * @see <a href="http://www.w3.org/TR/xpath20/#comments">XML Path Language (XPath)

         * 2.0, 2.6 Comments</a>

         * @returns

         * - SUCCESS if everything went ok

         * - ERROR if there was an error in parsing one or more comments

         * - END_OF_FILE if the end was reached

         */

        Tokenizer::TokenType consumeComment();

        /**

         * Determines whether @p code is a keyword

         * that is followed by a second keyword. For instance <tt>declare

         * function</tt>.

         */

        static inline bool isPhraseKeyword(const TokenType code);

        /**

         * A set of indexes into a QString, the one being passed to

         * normalizeEOL() whose characters shouldn't be normalized. */

        typedef QSet<int> CharacterSkips;

        /**

         * Returns @p input, normalized according to

         * <a href="http://www.w3.org/TR/xquery/#id-eol-handling">XQuery 1.0:

         * An XML Query Language, A.2.3 End-of-Line Handling</a>

         */

        static QString normalizeEOL(const QString &input,

                                    const CharacterSkips &characterSkips);

        inline bool atEnd() const

        {

            return m_pos == m_length;

        }

        Token nextToken();

        /**

         * Instead of recognizing and tokenizing embedded expressions in

         * direct attriute constructors, this function is essentially a mini

         * recursive-descent parser that has the necessary logic to recognize

         * embedded expressions and their potentially interfering string literals, in

         * order to scan to the very end of the attribute value, and return the

         * whole as a string.

         *

         * There is of course syntax errors this function will not detect, but

         * that is ok since the attributes will be parsed once more.

         *

         * An inelegant solution, but which gets the job done.

         *

         * @see commenceScanOnly(), resumeTokenizationFrom()

         */

        Token attributeAsRaw(const QChar separator,

                             int &stack,

                             const int startPos,

                             const bool inLiteral,

                             QString &result);

        const QString           m_data;

        const int               m_length;

        State                   m_state;

        QStack<State>           m_stateStack;

        int                     m_pos;

        /**

         * The current line number.

         *

         * The line number and column number both starts at 1.

         */

        int                     m_line;

        /**

         * The offset into m_length for where

         * the current column starts. So m_length - m_columnOffset

         * is the current column.

         *

         * The line number and column number both starts at 1.

         */

        int                     m_columnOffset;

        const NamePool::Ptr     m_namePool;

        QStack<Token>           m_tokenStack;

        QHash<QString, QChar>   m_charRefs;

        bool                    m_scanOnly;

        Q_DISABLE_COPY(XQueryTokenizer)

    };

}

QT_END_NAMESPACE

QT_END_HEADER

#endif