qgsexpressionnode.h

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/***************************************************************************
                               qgsexpressionnode.h
                             -------------------
    begin                : May 2017
    copyright            : (C) 2017 Matthias Kuhn
    email                : [email protected]
 ***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/


#ifndef QGSEXPRESSIONNODE_H
#define QGSEXPRESSIONNODE_H

#include <QSet>
#include <QVariant>
#include <QCoreApplication>

#include "qgis.h"

class QgsExpression;
class QgsExpressionContext;

class CORE_EXPORT QgsExpressionNode SIP_ABSTRACT
{

#ifdef SIP_RUN
    SIP_CONVERT_TO_SUBCLASS_CODE
    switch ( sipCpp->nodeType() )
    {
      case QgsExpressionNode::ntUnaryOperator:
        sipType = sipType_QgsExpressionNodeUnaryOperator;
        break;
      case QgsExpressionNode::ntBinaryOperator:
        sipType = sipType_QgsExpressionNodeBinaryOperator;
        break;
      case QgsExpressionNode::ntInOperator:
        sipType = sipType_QgsExpressionNodeInOperator;
        break;
      case QgsExpressionNode::ntFunction:
        sipType = sipType_QgsExpressionNodeFunction;
        break;
      case QgsExpressionNode::ntLiteral:
        sipType = sipType_QgsExpressionNodeLiteral;
        break;
      case QgsExpressionNode::ntColumnRef:
        sipType = sipType_QgsExpressionNodeColumnRef;
        break;
      case QgsExpressionNode::ntCondition:
        sipType = sipType_QgsExpressionNodeCondition;
        break;
      default:
        sipType = 0;
        break;
    }
    SIP_END
#endif

    Q_DECLARE_TR_FUNCTIONS( QgsExpressionNode )

  public:

    enum NodeType
    {
      ntUnaryOperator, 
      ntBinaryOperator, 
      ntInOperator, 
      ntFunction,  
      ntLiteral, 
      ntColumnRef, 
      ntCondition, 
      ntIndexOperator, 
    };


    struct NamedNode
    {
      public:

        NamedNode( const QString &name, QgsExpressionNode *node )
          : name( name )
          , node( node )
        {}

        QString name;

        QgsExpressionNode *node = nullptr;
    };

    class CORE_EXPORT NodeList
    {
      public:
        virtual ~NodeList();
        void append( QgsExpressionNode *node SIP_TRANSFER ) { mList.append( node ); mNameList.append( QString() ); }

        void append( QgsExpressionNode::NamedNode *node SIP_TRANSFER );

        int count() const { return mList.count(); }

        bool hasNamedNodes() const { return mHasNamedNodes; }

        QList<QgsExpressionNode *> list() { return mList; }

        QgsExpressionNode *at( int i ) { return mList.at( i ); }

        QStringList names() const { return mNameList; }

        QgsExpressionNode::NodeList *clone() const SIP_FACTORY;

        virtual QString dump() const;

      private:
        QList<QgsExpressionNode *> mList;
        QStringList mNameList;

        bool mHasNamedNodes = false;

      public:
    };

    virtual ~QgsExpressionNode() = default;

    virtual QgsExpressionNode::NodeType nodeType() const = 0;

    virtual QString dump() const = 0;

    QVariant eval( QgsExpression *parent, const QgsExpressionContext *context );

    virtual QgsExpressionNode *clone() const = 0;

    virtual QSet<QString> referencedColumns() const = 0;

    virtual QSet<QString> referencedVariables() const = 0;

    virtual QSet<QString> referencedFunctions() const = 0;

    virtual QList<const QgsExpressionNode *> nodes( ) const = 0; SIP_SKIP

    virtual bool needsGeometry() const = 0;

    virtual bool isStatic( QgsExpression *parent, const QgsExpressionContext *context ) const = 0;

    bool prepare( QgsExpression *parent, const QgsExpressionContext *context );

    int parserFirstLine = 0;

    int parserFirstColumn = 0;

    int parserLastLine = 0;

    int parserLastColumn = 0;

  protected:

    void cloneTo( QgsExpressionNode *target ) const SIP_SKIP;

  private:

    virtual bool prepareNode( QgsExpression *parent, const QgsExpressionContext *context ) = 0;

    virtual QVariant evalNode( QgsExpression *parent, const QgsExpressionContext *context ) = 0;

    bool mHasCachedValue = false;
    QVariant mCachedStaticValue;
};

Q_DECLARE_METATYPE( QgsExpressionNode * )

#endif // QGSEXPRESSIONNODE_H