qgsfeaturerequest.h

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/***************************************************************************
    qgsfeaturerequest.h
    ---------------------
    begin                : Mai 2012
    copyright            : (C) 2012 by Martin Dobias
    email                : wonder dot sk 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 QGSFEATUREREQUEST_H
#define QGSFEATUREREQUEST_H

#include <QFlags>

#include "qgsfeature.h"
#include "qgsrectangle.h"
#include "qgsexpression.h"
#include "qgssimplifymethod.h"

#include <QList>
typedef QList<int> QgsAttributeList;

class CORE_EXPORT QgsFeatureRequest
{
  public:
    enum Flag
    {
      NoFlags            = 0,
      NoGeometry         = 1,  
      SubsetOfAttributes = 2,  
      ExactIntersect     = 4   
    };
    Q_DECLARE_FLAGS( Flags, Flag )

    enum FilterType
    {
      FilterNone,       
      FilterRect,       
      FilterFid,        
      FilterExpression, 
      FilterFids        
    };

    static const QString AllAttributes;

    QgsFeatureRequest();
    explicit QgsFeatureRequest( QgsFeatureId fid );
    explicit QgsFeatureRequest( const QgsRectangle& rect );
    explicit QgsFeatureRequest( const QgsExpression& expr );
    QgsFeatureRequest( const QgsFeatureRequest& rh );

    QgsFeatureRequest& operator=( const QgsFeatureRequest& rh );

    ~QgsFeatureRequest();

    FilterType filterType() const { return mFilter; }

    QgsFeatureRequest& setFilterRect( const QgsRectangle& rect );
    const QgsRectangle& filterRect() const { return mFilterRect; }

    QgsFeatureRequest& setFilterFid( QgsFeatureId fid );
    const QgsFeatureId& filterFid() const { return mFilterFid; }

    QgsFeatureRequest& setFilterFids( QgsFeatureIds fids );
    const QgsFeatureIds& filterFids() const { return mFilterFids; }

    QgsFeatureRequest& setFilterExpression( const QString& expression );
    QgsExpression* filterExpression() const { return mFilterExpression; }

    QgsFeatureRequest& setFlags( Flags flags );
    const Flags& flags() const { return mFlags; }

    QgsFeatureRequest& setSubsetOfAttributes( const QgsAttributeList& attrs );
    const QgsAttributeList& subsetOfAttributes() const { return mAttrs; }

    QgsFeatureRequest& setSubsetOfAttributes( const QStringList& attrNames, const QgsFields& fields );

    QgsFeatureRequest& setSimplifyMethod( const QgsSimplifyMethod& simplifyMethod );
    const QgsSimplifyMethod& simplifyMethod() const { return mSimplifyMethod; }

    bool acceptFeature( const QgsFeature& feature );

    // TODO: in future
    // void setFilterNativeExpression(con QString& expr);   // using provider's SQL (if supported)
    // void setLimit(int limit);

  protected:
    FilterType mFilter;
    QgsRectangle mFilterRect;
    QgsFeatureId mFilterFid;
    QgsFeatureIds mFilterFids;
    QgsExpression* mFilterExpression;
    Flags mFlags;
    QgsAttributeList mAttrs;
    QgsSimplifyMethod mSimplifyMethod;
};

Q_DECLARE_OPERATORS_FOR_FLAGS( QgsFeatureRequest::Flags )


class QgsFeatureIterator;
class QgsAbstractFeatureIterator;

class CORE_EXPORT QgsAbstractFeatureSource
{
  public:
    virtual ~QgsAbstractFeatureSource();

    virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest& request ) = 0;

  protected:
    void iteratorOpened( QgsAbstractFeatureIterator* it );
    void iteratorClosed( QgsAbstractFeatureIterator* it );

    QSet< QgsAbstractFeatureIterator* > mActiveIterators;

    template<typename> friend class QgsAbstractFeatureIteratorFromSource;
};

#endif // QGSFEATUREREQUEST_H