qgssqlexpressioncompiler.h

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/***************************************************************************
                             qgssqlexpressioncompiler.h
                             --------------------------
    begin                : November 2015
    copyright            : (C) 2015 Nyall Dawson
    email                : nyall dot dawson at gmail dot com
 ***************************************************************************
 *                                                                         *
 *   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 QGSSQLEXPRESSIONCOMPILER_H
#define QGSSQLEXPRESSIONCOMPILER_H
 
 
#include "qgis_core.h"
#include "qgsexpressionnodeimpl.h"
#include "qgsfields.h"
 
#define SIP_NO_FILE
 
class QgsExpression;
class QgsExpressionNode;

 
class CORE_EXPORT QgsSqlExpressionCompiler
{
  public:

    enum Result
    {
      None, 
      Complete, 
      Partial, 
      Fail 
    };

    enum Flag
    {
      CaseInsensitiveStringMatch = 1,  
      LikeIsCaseInsensitive = 1 << 1, 
      NoNullInBooleanLogic = 1 << 2, 
      NoUnaryMinus = 1 << 3, 
      IntegerDivisionResultsInInteger = 1 << 4, 
    };
    Q_DECLARE_FLAGS( Flags, Flag )
 
    
    explicit QgsSqlExpressionCompiler( const QgsFields &fields, QgsSqlExpressionCompiler::Flags flags = Flags(), bool ignoreStaticNodes = false );
    virtual ~QgsSqlExpressionCompiler() = default;

    virtual Result compile( const QgsExpression *exp );

    virtual QString result();

    bool opIsStringComparison( QgsExpressionNodeBinaryOperator::BinaryOperator op );
 
  protected:

    virtual QString quotedIdentifier( const QString &identifier );

    virtual QString quotedValue( const QVariant &value, bool &ok );

    virtual Result compileNode( const QgsExpressionNode *node, QString &str );

    virtual QString sqlFunctionFromFunctionName( const QString &fnName ) const;

    virtual QStringList sqlArgumentsFromFunctionName( const QString &fnName, const QStringList &fnArgs ) const;

    virtual QString castToReal( const QString &value ) const;

    virtual QString castToText( const QString &value ) const;

    virtual QString castToInt( const QString &value ) const;

    virtual Result replaceNodeByStaticCachedValueIfPossible( const QgsExpressionNode *node, QString &str );
 
    QString mResult;
    QgsFields mFields;
 
  private:
 
    Flags mFlags;
 
    bool mIgnoreStaticNodes = false;
 
    bool nodeIsNullLiteral( const QgsExpressionNode *node ) const;
 
};
 
Q_DECLARE_OPERATORS_FOR_FLAGS( QgsSqlExpressionCompiler::Flags )
 
#endif // QGSSQLEXPRESSIONCOMPILER_H