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

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

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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_ParserContext_H

#define Patternist_ParserContext_H

#include <QFlags>

#include <QSharedData>

#include <QStack>

#include <QStringList>

#include <QtGlobal>

#include <QXmlQuery>

#include "qbuiltintypes_p.h"

#include "qfunctionsignature_p.h"

#include "qorderby_p.h"

#include "qtemplatemode_p.h"

#include "quserfunctioncallsite_p.h"

#include "quserfunction_p.h"

#include "qvariabledeclaration_p.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist

{

    class Tokenizer;

    /**

     * @short Contains data used when parsing and tokenizing.

     *

     * When ExpressionFactory::create() is called, an instance of this class

     * is passed to the scanner and parser. It holds all information that is

     * needed to create the expression.

     *

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

     */

    class ParserContext : public QSharedData

    {

    public:

        typedef QExplicitlySharedDataPointer<ParserContext> Ptr;

        enum PrologDeclaration

        {

            BoundarySpaceDecl               = 1,

            DefaultCollationDecl            = 2,

            BaseURIDecl                     = 4,

            ConstructionDecl                = 8,

            OrderingModeDecl                = 16,

            EmptyOrderDecl                  = 32,

            CopyNamespacesDecl              = 64,

            DeclareDefaultElementNamespace  = 128,

            DeclareDefaultFunctionNamespace = 256

        };

        typedef QFlags<PrologDeclaration> PrologDeclarations;

        /**

         * Constructs a ParserContext instance.

         *

         * @param context the static context as defined in XPath. This contain

         * namespace bindings, error handler, and other information necessary

         * for creating an XPath expression.

         * @param lang the particular XPath language sub-set that should be parsed

         * @param tokenizer the Tokenizer to use.

         * @see ExpressionFactory::LanguageAccent

         */

        ParserContext(const StaticContext::Ptr &context,

                      const QXmlQuery::QueryLanguage lang,

                      Tokenizer *const tokenizer);

        /**

         * @short Removes the recently pushed variables from

         * scope. The amount of removed variables is @p amount.

         *

         * finalizePushedVariable() can be seen as popping the variable.

         *

         */

        void finalizePushedVariable(const int amount = 1,

                                    const bool shouldPop = true);

        inline VariableSlotID allocatePositionalSlot()

        {

            ++m_positionSlot;

            return m_positionSlot;

        }

        inline VariableSlotID allocateExpressionSlot()

        {

            const VariableSlotID retval = m_expressionSlot;

            ++m_expressionSlot;

            return retval;

        }

        inline VariableSlotID allocateGlobalVariableSlot()

        {

            ++m_globalVariableSlot;

            return m_globalVariableSlot;

        }

        inline bool hasDeclaration(const PrologDeclaration decl) const

        {

            return m_prologDeclarations.testFlag(decl);

        }

        inline void registerDeclaration(const PrologDeclaration decl)

        {

            m_prologDeclarations |= decl;

        }

        /**

         * The namespaces declared with <tt>declare namespace</tt>.

         */

        QStringList declaredPrefixes;

        /**

         * This is a temporary stack, used for keeping variables in scope,

         * such as for function arguments & let clauses.

         */

        VariableDeclaration::Stack variables;

        inline bool isXSLT() const

        {

            return languageAccent == QXmlQuery::XSLT20;

        }

        const StaticContext::Ptr staticContext;

        /**

         * We don't store a Tokenizer::Ptr here, because then we would get a

         * circular referencing between ParserContext and XSLTTokenizer, and

         * hence they would never destruct.

         */

        Tokenizer *const tokenizer;

        const QXmlQuery::QueryLanguage languageAccent;

        /**

         * Only used in the case of XSL-T. Is the name of the initial template

         * to call. If null, no name was provided, and regular template

         * matching should be done.

         */

        QXmlName initialTemplateName;

        /**

         * Used when parsing direct element constructors. It is used

         * for ensuring tags are well-balanced.

         */

        QStack<QXmlName> tagStack;

        /**

         * The actual expression, the Query. This member may be @c null,

         * such as in the case of an XQuery library module.

         */

        Expression::Ptr queryBody;

        /**

         * The user functions declared in the prolog.

         */

        UserFunction::List userFunctions;

        /**

         * Contains all calls to user defined functions.

         */

        UserFunctionCallsite::List userFunctionCallsites;

        /**

         * All variables declared with <tt>declare variable</tt>.

         */

        VariableDeclaration::List declaredVariables;

        inline VariableSlotID currentPositionSlot() const

        {

            return m_positionSlot;

        }

        inline VariableSlotID currentExpressionSlot() const

        {

            return m_expressionSlot;

        }

        inline void restoreNodeTestSource()

        {

            nodeTestSource = BuiltinTypes::element;

        }

        inline VariableSlotID allocateCacheSlot()

        {

            return ++m_evaluationCacheSlot;

        }

        inline VariableSlotID allocateCacheSlots(const int count)

        {

            const VariableSlotID retval = m_evaluationCacheSlot + 1;

            m_evaluationCacheSlot += count + 1;

            return retval;

        }

        ItemType::Ptr nodeTestSource;

        QStack<Expression::Ptr> typeswitchSource;

        /**

         * The library module namespace set with <tt>declare module</tt>.

         */

        QXmlName::NamespaceCode moduleNamespace;

        /**

         * When a direct element constructor is processed, resolvers are

         * created in order to carry the namespace declarations. In such case,

         * the old resolver is pushed here.

         */

        QStack<NamespaceResolver::Ptr> resolvers;

        /**

         * This is used for handling the following obscene case:

         *

         * - <tt>\<e\>{1}{1}\<\/e\></tt> produce <tt>\<e\>11\</e\></tt>

         * - <tt>\<e\>{1, 1}\<\/e\></tt> produce <tt>\<e\>1 1\</e\></tt>

         *

         * This boolean tracks whether the previous reduction inside element

         * content was done with an enclosed expression.

         */

        bool isPreviousEnclosedExpr;

        int elementConstructorDepth;

        QStack<bool> scanOnlyStack;

        QStack<OrderBy::Stability> orderStability;

        /**

         * Whether any prolog declaration that must occur after the first

         * group has been encountered.

         */

        bool hasSecondPrologPart;

        bool preserveNamespacesMode;

        bool inheritNamespacesMode;

        /**

         * Contains all named templates. Since named templates

         * can also have rules, each body may also be in templateRules.

         */

        QHash<QXmlName, Template::Ptr>  namedTemplates;

        /**

         * All the @c xsl:call-template instructions that we have encountered.

         */

        QVector<Expression::Ptr>         templateCalls;

        /**

         * If we're in XSL-T, and a variable reference is encountered

         * which isn't in-scope, it's added to this hash since a global

         * variable declaration may appear later on.

         *

         * We use a multi hash, since we can encounter several references to

         * the same variable before it's declared.

         */

        QMultiHash<QXmlName, Expression::Ptr> unresolvedVariableReferences;

        /**

         *

         * Contains the encountered template rules, as opposed

         * to named templates.

         *

         * The key is the name of the template mode. If it's a default

         * constructed value, it's the default mode.

         *

         * Since templates rules may also be named, each body may also be in

         * namedTemplates.

         *

         * To be specific, the values are not the templates, the values are

         * modes, and the TemplateMode contains the patterns and bodies.

         */

        QHash<QXmlName, TemplateMode::Ptr>  templateRules;

        /**

         * @short Returns the TemplateMode for @p modeName or @c null if the

         * mode being asked for is @c #current.

         */

        TemplateMode::Ptr modeFor(const QXmlName &modeName)

        {

            /* #current is not a mode, so it cannot contain templates. #current

             * specifies how to look up templates wrt. mode. This check helps

             * code that calls us, asking for the mode it needs to lookup in.

             */

            if(modeName == QXmlName(StandardNamespaces::InternalXSLT, StandardLocalNames::current))

                return TemplateMode::Ptr();

            TemplateMode::Ptr &mode = templateRules[modeName];

            if(!mode)

                mode = TemplateMode::Ptr(new TemplateMode(modeName));

            Q_ASSERT(templateRules[modeName]);

            return mode;

        }

        inline TemplatePattern::ID allocateTemplateID()

        {

            ++m_currentTemplateID;

            return m_currentTemplateID;

        }

        /**

         * The @c xsl:param appearing inside template.

         */

        VariableDeclaration::List templateParameters;

        /**

         * The @c xsl:with-param appearing in template calling instruction.

         */

        WithParam::Hash templateWithParams;

        inline void templateParametersHandled()

        {

            finalizePushedVariable(templateParameters.count());

            templateParameters.clear();

        }

        inline void templateWithParametersHandled()

        {

            templateWithParams.clear();

        }

        inline bool isParsingWithParam() const

        {

            return m_isParsingWithParam.top();

        }

        void startParsingWithParam()

        {

            m_isParsingWithParam.push(true);

        }

        void endParsingWithParam()

        {

            m_isParsingWithParam.pop();

        }

        /**

         * This is used to deal with XSL-T's exception to the @c node() type,

         * which doesn't match document nodes.

         */

        bool                                isParsingPattern;

        ImportPrecedence                    currentImportPrecedence;

        bool isFirstTemplate() const

        {

            return m_currentTemplateID == InitialTemplateID;

        }

        /**

         * Whether we're processing XSL-T 1.0 code.

         */

        QStack<bool> isBackwardsCompat;

    private:

        enum

        {

            InitialTemplateID = -1

        };

        VariableSlotID                      m_evaluationCacheSlot;

        VariableSlotID                      m_expressionSlot;

        VariableSlotID                      m_positionSlot;

        PrologDeclarations                  m_prologDeclarations;

        VariableSlotID                      m_globalVariableSlot;

        TemplatePattern::ID                 m_currentTemplateID;

        /**

         * The default is @c false. If we're not parsing @c xsl:with-param,

         * hence parsing @c xsl:param, the value has changed.

         */

        QStack<bool>                        m_isParsingWithParam;

        Q_DISABLE_COPY(ParserContext)

    };

}

QT_END_NAMESPACE

QT_END_HEADER

#endif