qgsvectordataprovider.h

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/***************************************************************************
    qgsvectordataprovider.h - DataProvider Interface for vector layers
     --------------------------------------
    Date                 : 23-Sep-2004
    Copyright            : (C) 2004 by Marco Hugentobler
    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 QGSVECTORDATAPROVIDER_H
#define QGSVECTORDATAPROVIDER_H

class QTextCodec;

#include <QList>
#include <QSet>
#include <QMap>
#include <QHash>

//QGIS Includes
#include "qgis.h"
#include "qgsdataprovider.h"
#include "qgsfeature.h"
#include "qgsfield.h"
#include "qgsrectangle.h"
#include "qgsaggregatecalculator.h"

typedef QList<int> QgsAttributeList;
typedef QSet<int> QgsAttributeIds;
typedef QHash<int, QString> QgsAttrPalIndexNameHash;

class QgsFeatureIterator;
class QgsTransaction;

#include "qgsfeaturerequest.h"

class CORE_EXPORT QgsVectorDataProvider : public QgsDataProvider
{
    Q_OBJECT

    friend class QgsTransaction;
    friend class QgsVectorLayerEditBuffer;

  public:

    // If you add to this, please also add to capabilitiesString()
    enum Capability
    {
      NoCapabilities =                              0,
      AddFeatures =                                 1,
      DeleteFeatures =                              1 <<  1,
      ChangeAttributeValues =                       1 <<  2,
      AddAttributes =                               1 <<  3,
      DeleteAttributes =                            1 <<  4,
      SaveAsShapefile =                             1 <<  5,
      CreateSpatialIndex =                          1 <<  6,
      SelectAtId =                                  1 <<  7,
      ChangeGeometries =                            1 <<  8,
      SelectGeometryAtId =                          1 <<  9,
      RandomSelectGeometryAtId =                    1 << 10,
      SequentialSelectGeometryAtId =                1 << 11,
      CreateAttributeIndex =                        1 << 12,
      SelectEncoding =                              1 << 13,
      SimplifyGeometries =                          1 << 14,
      SimplifyGeometriesWithTopologicalValidation = 1 << 15,
      TransactionSupport =                          1 << 16,
      CircularGeometries =                          1 << 17,
      ChangeFeatures =                              1 << 18,
      RenameAttributes =                            1 << 19,
    };

    const static int EditingCapabilities = AddFeatures | DeleteFeatures |
                                           ChangeAttributeValues | ChangeGeometries | AddAttributes | DeleteAttributes |
                                           RenameAttributes;

    QgsVectorDataProvider( const QString& uri = QString() );

    virtual ~QgsVectorDataProvider();

    virtual QgsAbstractFeatureSource *featureSource() const = 0;

    virtual QString storageType() const;

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

    virtual QGis::WkbType geometryType() const = 0;

    virtual long featureCount() const = 0;

    // TODO QGIS 3: return by value
    virtual const QgsFields &fields() const = 0;

    virtual QString dataComment() const;

    virtual QVariant minimumValue( int index );

    virtual QVariant maximumValue( int index );

    virtual void uniqueValues( int index, QList<QVariant> &uniqueValues, int limit = -1 );

    virtual QVariant aggregate( QgsAggregateCalculator::Aggregate aggregate,
                                int index,
                                const QgsAggregateCalculator::AggregateParameters& parameters,
                                QgsExpressionContext* context,
                                bool& ok );

    virtual void enumValues( int index, QStringList& enumList ) { Q_UNUSED( index ); enumList.clear(); }

    virtual bool addFeatures( QgsFeatureList &flist );

    virtual bool deleteFeatures( const QgsFeatureIds &id );

    virtual bool addAttributes( const QList<QgsField> &attributes );

    virtual bool deleteAttributes( const QgsAttributeIds &attributes );

    virtual bool renameAttributes( const QgsFieldNameMap& renamedAttributes );

    virtual bool changeAttributeValues( const QgsChangedAttributesMap &attr_map );

    virtual bool changeFeatures( const QgsChangedAttributesMap &attr_map,
                                 const QgsGeometryMap &geometry_map );

    virtual QVariant defaultValue( int fieldId, bool forceLazyEval = false );

    virtual bool changeGeometryValues( const QgsGeometryMap &geometry_map );

    virtual bool createSpatialIndex();

    virtual bool createAttributeIndex( int field );

    virtual int capabilities() const;

    QString capabilitiesString() const;

    virtual void setEncoding( const QString& e );

    QString encoding() const;

    int fieldNameIndex( const QString& fieldName ) const;

    QMap<QString, int> fieldNameMap() const;

    virtual QgsAttributeList attributeIndexes();

    virtual QgsAttributeList pkAttributeIndexes() { return QgsAttributeList(); }

    virtual QgsAttrPalIndexNameHash palAttributeIndexNames() const { return mAttrPalIndexName; }

    bool supportedType( const QgsField &field ) const;

    struct NativeType
    {
      NativeType( const QString& typeDesc, const QString& typeName, QVariant::Type type, int minLen = 0, int maxLen = 0, int minPrec = 0, int maxPrec = 0 )
          : mTypeDesc( typeDesc )
          , mTypeName( typeName )
          , mType( type )
          , mMinLen( minLen )
          , mMaxLen( maxLen )
          , mMinPrec( minPrec )
          , mMaxPrec( maxPrec )
      {}

      QString mTypeDesc;
      QString mTypeName;
      QVariant::Type mType;
      int mMinLen;
      int mMaxLen;
      int mMinPrec;
      int mMaxPrec;
    };

    const QList< NativeType > &nativeTypes() const;

    virtual bool doesStrictFeatureTypeCheck() const { return true;}

    static const QStringList &availableEncodings();

    bool hasErrors();

    void clearErrors();

    QStringList errors();


    virtual bool isSaveAndLoadStyleToDBSupported() { return false; }

    static QVariant convertValue( QVariant::Type type, const QString& value );

    virtual QgsTransaction* transaction() const { return nullptr; }

    virtual void forceReload()
    {
      emit dataChanged();
    }

    virtual QSet<QString> layerDependencies() const;

  signals:
    void raiseError( const QString& msg );

  protected:
    void clearMinMaxCache();
    void fillMinMaxCache();

    bool mCacheMinMaxDirty;
    QMap<int, QVariant> mCacheMinValues, mCacheMaxValues;

    QTextCodec* mEncoding;

    QgsAttributeList mAttributesToFetch;

    QList< NativeType > mNativeTypes;

    void pushError( const QString& msg );

    QgsAttrPalIndexNameHash mAttrPalIndexName;

    QgsGeometry* convertToProviderType( const QgsGeometry* geom ) const;

  private:
    QMap<QString, QVariant::Type> mOldTypeList;

    QStringList mErrors;

    static QStringList smEncodings;

    virtual void setTransaction( QgsTransaction* /*transaction*/ ) {}

};


#endif