qexpression_p.h

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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_Expression_H
#define Patternist_Expression_H

#include <QFlags>
#include <QSharedData>

#include "qcppcastinghelper_p.h"
#include "qdebug_p.h"
#include "qdynamiccontext_p.h"
#include "qexpressiondispatch_p.h"
#include "qitem_p.h"
#include "qsequencetype_p.h"
#include "qsourcelocationreflection_p.h"
#include "qstaticcontext_p.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

template<typename T> class QList;
template<typename T> class QVector;

namespace QPatternist
{
    template<typename T, typename ListType> class ListIterator;
    class OptimizationPass;

    class Q_AUTOTEST_EXPORT Expression : public QSharedData
                                       , public CppCastingHelper<Expression>
                                       , public SourceLocationReflection
    {
    public:
        typedef QExplicitlySharedDataPointer<Expression> Ptr;

        typedef QExplicitlySharedDataPointer<const Expression> ConstPtr;

        typedef QList<Expression::Ptr> List;

        typedef QVector<Expression::Ptr> Vector;

        typedef QT_PREPEND_NAMESPACE(QAbstractXmlForwardIterator<Expression::Ptr>)
            QAbstractXmlForwardIterator;

        enum Property
        {
            UseContextItem              = 1,

            DisableElimination          = 1 << 1,

            IsEvaluated                 = 1 << 2,

            DisableTypingDeduction      = 1 << 3,

            EmptynessFollowsChild       = 1 << 4,

            RewriteToEmptyOnEmpty       = 1 << 5,

            RequiresFocus               = 1 << 6,

            AffectsOrderOnly            = 1 << 7,

            RequiresContextItem         = (1 << 8) | RequiresFocus,

            CreatesFocusForLast         = 1 << 9,

            LastOperandIsCollation      = 1 << 10,

            DependsOnLocalVariable      = (1 << 11) | DisableElimination,

            EvaluationCacheRedundant       = (1 << 12),

            IsNodeConstructor           = 1 << 13,

            RequiresCurrentItem         = 1 << 14
        };

        typedef QFlags<Property> Properties;

        enum ID
        {
            IDBooleanValue = 1,

            IDCountFN,

            IDEmptyFN,

            IDExistsFN,

            IDExpressionSequence,

            IDGeneralComparison,

            IDIfThenClause,

            IDIgnorableExpression,

            IDIntegerValue,

            IDPositionFN,

            IDStringValue,

            IDValueComparison,

            IDRangeVariableReference,

            IDContextItem,

            IDUserFunctionCallsite,

            IDExpressionVariableReference,

            IDAttributeConstructor,

            IDUpperCaseFN,

            IDLowerCaseFN,

            IDFirstItemPredicate,
            IDEmptySequence,
            IDReturnOrderBy,
            IDLetClause,
            IDForClause,
            IDPath,
            IDNamespaceConstructor,
            IDArgumentReference,
            IDGenericPredicate,
            IDAxisStep,

            IDFloat,

            IDCombineNodes,
            IDUnresolvedVariableReference,
            IDCardinalityVerifier
        };

        inline Expression()
        {
        }
        virtual ~Expression();

        virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;

        virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;

        virtual bool evaluateEBV(const DynamicContext::Ptr &context) const;

        virtual void evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const;

        virtual Expression::List operands() const = 0;

        virtual void setOperands(const Expression::List &operands) = 0;

        virtual SequenceType::Ptr staticType() const = 0;

        virtual SequenceType::List expectedOperandTypes() const = 0;

        virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
                                          const SequenceType::Ptr &reqType);

        virtual Expression::Ptr compress(const StaticContext::Ptr &context);

        virtual Properties properties() const;

        virtual Properties dependencies() const;

        Properties deepProperties() const;

        inline bool isEvaluated() const;

        inline bool is(const ID id) const;

        inline bool has(const Property prop) const;

        inline bool hasDependency(const Property prop) const;

        virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const = 0;

        virtual ID id() const;

        virtual QList<QExplicitlySharedDataPointer<OptimizationPass> > optimizationPasses() const;

        virtual ItemType::Ptr expectedContextItemType() const;

        virtual ItemType::Ptr newFocusType() const;

        virtual const SourceLocationReflection *actualReflection() const;

        virtual QString description() const;

        virtual void announceFocusType(const ItemType::Ptr &itemType);

        static inline void rewrite(Expression::Ptr &old,
                                   const Expression::Ptr &New,
                                   const StaticContext::Ptr &context);

        inline const Expression::Ptr &rewrite(const Expression::Ptr &to,
                                              const StaticContext::Ptr &context) const;

        virtual PatternPriority patternPriority() const;

    protected:

        virtual bool compressOperands(const StaticContext::Ptr &) = 0;

        void typeCheckOperands(const StaticContext::Ptr &context);

    private:
        static Expression::Ptr invokeOptimizers(const Expression::Ptr &expr,
                                                const StaticContext::Ptr &context);
        inline StaticContext::Ptr finalizeStaticContext(const StaticContext::Ptr &context) const;

        Expression::Ptr constantPropagate(const StaticContext::Ptr &context) const;

        Q_DISABLE_COPY(Expression)
    };

    Q_DECLARE_OPERATORS_FOR_FLAGS(Expression::Properties)

    inline bool Expression::is(const Expression::ID i) const
    {
        return id() == i;
    }

    inline bool Expression::isEvaluated() const
    {
        return has(IsEvaluated);
    }

    inline bool Expression::has(const Expression::Property prop) const
    {
        return properties().testFlag(prop);
    }

    inline bool Expression::hasDependency(const Expression::Property prop) const
    {
        return dependencies().testFlag(prop);
    }

    inline void Expression::rewrite(Expression::Ptr &old,
                                    const Expression::Ptr &New,
                                    const StaticContext::Ptr &context)
    {
        Q_ASSERT(old);
        Q_ASSERT(New);

        if(old != New)
        {
            pDebug() << "AST REWRITE:" << old.data() << "to" << New.data()
                     << '(' << old->actualReflection() << "to" << New->actualReflection() << ", "
                     << old->description() << "to" << New->description() << ')';

            /* The order of these two lines is significant.. */
            context->addLocation(New.data(), context->locationFor(old->actualReflection()));
            old = New;
        }
    }

    inline const Expression::Ptr &Expression::rewrite(const Expression::Ptr &to,
                                                      const StaticContext::Ptr &context) const
    {
        context->addLocation(to.data(), context->locationFor(this));
        return to;
    }
}

Q_DECLARE_TYPEINFO(QPatternist::Expression::Ptr, Q_MOVABLE_TYPE);

QT_END_NAMESPACE

QT_END_HEADER

#endif