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 "qgis_core.h"
#include <QList>
#include <QSet>
#include <QMap>
#include <QHash>
 
//QGIS Includes
#include "qgis_sip.h"
#include "qgsdataprovider.h"
#include "qgsfeature.h"
#include "qgsaggregatecalculator.h"
#include "qgsmaplayerdependency.h"
#include "qgsrelation.h"
#include "qgsfeaturesink.h"
#include "qgsfeaturesource.h"
#include "qgsfeaturerequest.h"
#include "qgsvectordataprovidertemporalcapabilities.h"
 
typedef QList<int> QgsAttributeList SIP_SKIP;
typedef QSet<int> QgsAttributeIds SIP_SKIP;
typedef QHash<int, QString> QgsAttrPalIndexNameHash;
 
class QgsFeatureIterator;
class QgsTransaction;
class QgsFeedback;
class QgsFeatureRenderer;
class QgsAbstractVectorLayerLabeling;
 
 
class CORE_EXPORT QgsVectorDataProvider : public QgsDataProvider, public QgsFeatureSink, public QgsFeatureSource
{
    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, 
      CreateSpatialIndex = 1 <<  6, 
      SelectAtId = 1 <<  7, 
      ChangeGeometries = 1 <<  8, 
      SelectEncoding = 1 << 13, 
      CreateAttributeIndex = 1 << 12, 
      SimplifyGeometries = 1 << 14, 
      SimplifyGeometriesWithTopologicalValidation = 1 << 15, 
      TransactionSupport = 1 << 16, 
      CircularGeometries = 1 << 17, 
      ChangeFeatures = 1 << 18, 
      RenameAttributes = 1 << 19, 
      FastTruncate = 1 << 20, 
      ReadLayerMetadata = 1 << 21, 
      WriteLayerMetadata = 1 << 22, 
      CancelSupport = 1 << 23, 
      CreateRenderer = 1 << 24, 
      CreateLabeling = 1 << 25, 
      ReloadData = 1 << 26, 
    };
 
    Q_DECLARE_FLAGS( Capabilities, Capability )
 
    
    static const int EditingCapabilities = AddFeatures | DeleteFeatures |
                                           ChangeAttributeValues | ChangeGeometries | AddAttributes | DeleteAttributes |
                                           RenameAttributes;
 
    enum FeatureCountState
    {
      Uncounted = -2,
      UnknownCount = -1,
    };
 
    QgsVectorDataProvider( const QString &uri = QString(),
                           const QgsDataProvider::ProviderOptions &providerOptions = QgsDataProvider::ProviderOptions(),
                           QgsDataProvider::ReadFlags flags = QgsDataProvider::ReadFlags() );
 
    virtual QgsAbstractFeatureSource *featureSource() const = 0 SIP_FACTORY;
 
    virtual QString storageType() const;
 
    QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) const override = 0;
 
    QgsWkbTypes::Type wkbType() const override = 0;
 
    long featureCount() const override = 0;
 
    virtual bool empty() const;
 
    QgsFeatureSource::FeatureAvailability hasFeatures() const override;
 
    QgsFields fields() const override = 0;
 
    QgsCoordinateReferenceSystem sourceCrs() const override;
    QgsRectangle sourceExtent() const override;
    QString sourceName() const override { return QString(); }
 
    virtual QString dataComment() const override;
 
    QVariant minimumValue( int index ) const override;
 
    QVariant maximumValue( int index ) const override;
 
    virtual QStringList uniqueStringsMatching( int index, const QString &substring, int limit = -1,
        QgsFeedback *feedback = nullptr ) const;
 
    virtual QVariant aggregate( QgsAggregateCalculator::Aggregate aggregate,
                                int index,
                                const QgsAggregateCalculator::AggregateParameters &parameters,
                                QgsExpressionContext *context,
                                bool &ok,
                                QgsFeatureIds *fids = nullptr ) const;
 
    virtual void enumValues( int index, QStringList &enumList SIP_OUT ) const { Q_UNUSED( index ) enumList.clear(); }
 
    bool addFeatures( QgsFeatureList &flist SIP_INOUT, QgsFeatureSink::Flags flags = QgsFeatureSink::Flags() ) override;
    QString lastError() const override;
 
    virtual bool deleteFeatures( const QgsFeatureIds &id );
 
    virtual bool truncate();
 
    virtual bool cancelReload();
 
    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 fieldIndex ) const;
 
    virtual QString defaultValueClause( int fieldIndex ) const;
 
    QgsFieldConstraints::Constraints fieldConstraints( int fieldIndex ) const;
 
    virtual bool skipConstraintCheck( int fieldIndex, QgsFieldConstraints::Constraint constraint, const QVariant &value = QVariant() ) const;
 
    virtual bool changeGeometryValues( const QgsGeometryMap &geometry_map );
 
    virtual bool createSpatialIndex();
 
    virtual bool createAttributeIndex( int field );
 
    Q_INVOKABLE virtual QgsVectorDataProvider::Capabilities 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() const;
 
    virtual QgsAttributeList pkAttributeIndexes() const;
 
    virtual QgsAttrPalIndexNameHash palAttributeIndexNames() const;
 
    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, QVariant::Type subType = QVariant::Invalid )
        : mTypeDesc( typeDesc )
        , mTypeName( typeName )
        , mType( type )
        , mMinLen( minLen )
        , mMaxLen( maxLen )
        , mMinPrec( minPrec )
        , mMaxPrec( maxPrec )
        , mSubType( subType )
      {}
 
      QString mTypeDesc;
      QString mTypeName;
      QVariant::Type mType;
      int mMinLen;
      int mMaxLen;
      int mMinPrec;
      int mMaxPrec;
      QVariant::Type mSubType;
    };
 
    QList< QgsVectorDataProvider::NativeType > nativeTypes() const;
 
    virtual bool doesStrictFeatureTypeCheck() const { return true; }
 
    static QStringList availableEncodings();
 
    bool hasErrors() const;
 
    void clearErrors();
 
    QStringList errors() const;
 
    virtual bool isSaveAndLoadStyleToDatabaseSupported() const;
 
    virtual bool isDeleteStyleFromDatabaseSupported() const;
 
    virtual QgsFeatureRenderer *createRenderer( const QVariantMap &configuration = QVariantMap() ) const SIP_FACTORY;
 
    virtual QgsAbstractVectorLayerLabeling *createLabeling( const QVariantMap &configuration = QVariantMap() ) const SIP_FACTORY;
 
    static QVariant convertValue( QVariant::Type type, const QString &value );
 
    virtual QgsTransaction *transaction() const;
 
    Q_DECL_DEPRECATED virtual void forceReload() SIP_DEPRECATED { reloadData(); }
 
    virtual QSet<QgsMapLayerDependency> dependencies() const;
 
    virtual QList<QgsRelation> discoverRelations( const QgsVectorLayer *self, const QList<QgsVectorLayer *> &layers ) const;
 
    virtual QVariantMap metadata() const { return QVariantMap(); }
 
    virtual QString translateMetadataKey( const QString &mdKey ) const { return mdKey; }
 
    virtual QString translateMetadataValue( const QString &mdKey, const QVariant &value ) const { Q_UNUSED( mdKey ) return value.toString(); }
 
    virtual bool hasMetadata() const { return true; }
 
    virtual void handlePostCloneOperations( QgsVectorDataProvider *source );
 
    QgsVectorDataProviderTemporalCapabilities *temporalCapabilities() override;
    const QgsVectorDataProviderTemporalCapabilities *temporalCapabilities() const override SIP_SKIP;
 
  signals:
 
    void raiseError( const QString &msg ) const;
 
  protected:
 
    void clearMinMaxCache();
 
    void fillMinMaxCache() const;
 
    void pushError( const QString &msg ) const;
 
    QgsGeometry convertToProviderType( const QgsGeometry &geom ) const;
 
    void setNativeTypes( const QList<QgsVectorDataProvider::NativeType> &nativeTypes );
 
    QTextCodec *textEncoding() const;
 
  private:
    mutable bool mCacheMinMaxDirty = true;
    mutable QMap<int, QVariant> mCacheMinValues, mCacheMaxValues;
 
    QTextCodec *mEncoding = nullptr;
 
    QgsAttributeList mAttributesToFetch;
 
    QList< NativeType > mNativeTypes;
 
    mutable QStringList mErrors;
 
    std::unique_ptr< QgsVectorDataProviderTemporalCapabilities > mTemporalCapabilities;
 
    static QStringList sEncodings;
 
    virtual void setTransaction( QgsTransaction * /*transaction*/ ) {}
};
 
Q_DECLARE_OPERATORS_FOR_FLAGS( QgsVectorDataProvider::Capabilities )
 
#endif