qgsdataprovider.h

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/***************************************************************************
                qgsdataprovider.h - DataProvider Interface class
                     --------------------------------------
    Date                 : 09-Sep-2003
    Copyright            : (C) 2003 by Gary E.Sherman
    email                : sherman at mrcc.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 QQGSDATAPROVIDER_H
#define QQGSDATAPROVIDER_H

#include "qgis_core.h"
#include <QDateTime>
#include <QObject>
#include <QString>
#include <QStringList>
#include <QMutex>

//#include "qgsdataitem.h"
#include "qgsdatasourceuri.h"
#include "qgscoordinatetransformcontext.h"
#include "qgslayermetadata.h"
#include "qgserror.h"

class QgsRectangle;
class QgsCoordinateReferenceSystem;


class CORE_EXPORT QgsDataProvider : public QObject
{

#ifdef SIP_RUN
    SIP_CONVERT_TO_SUBCLASS_CODE
    if ( qobject_cast<QgsVectorDataProvider *>( sipCpp ) )
    {
      sipType = sipType_QgsVectorDataProvider;
    }
    else if ( qobject_cast<QgsRasterDataProvider *>( sipCpp ) )
    {
      sipType = sipType_QgsRasterDataProvider;
    }
    else if ( qobject_cast<QgsMeshDataProvider *>( sipCpp ) )
    {
      sipType = sipType_QgsMeshDataProvider;
    }
    else
    {
      sipType = 0;
    }
    SIP_END
#endif
    Q_OBJECT

  public:

    // TODO QGIS 4: (re)move DataCapability as this enum is really meant for data items rather than data providers

    enum DataCapability
    {
      NoDataCapabilities  = 0,
      File                = 1,
      Dir                 = 1 << 1,
      Database            = 1 << 2,
      Net                 = 1 << 3  // Internet source
    };
    Q_DECLARE_FLAGS( DataCapabilities, DataCapability )

    
    enum ProviderProperty
    {
      EvaluateDefaultValues,       
      CustomData   = 3000          
    };


    struct ProviderOptions
    {
      QgsCoordinateTransformContext transformContext;
    };

    QgsDataProvider( const QString &uri = QString(), const QgsDataProvider::ProviderOptions &providerOptions = QgsDataProvider::ProviderOptions() );

    virtual QgsCoordinateReferenceSystem crs() const = 0;

    virtual void setDataSourceUri( const QString &uri )
    {
      mDataSourceURI = uri;
    }

    virtual QString dataSourceUri( bool expandAuthConfig = false ) const
    {
      if ( expandAuthConfig && mDataSourceURI.contains( QLatin1String( "authcfg" ) ) )
      {
        QgsDataSourceUri uri( mDataSourceURI );
        return uri.uri( expandAuthConfig );
      }
      else
      {
        return mDataSourceURI;
      }
    }

    void setUri( const QgsDataSourceUri &uri )
    {
      mDataSourceURI = uri.uri( true );
    }

    QgsDataSourceUri uri() const
    {
      return QgsDataSourceUri( mDataSourceURI );
    }

    virtual QgsRectangle extent() const = 0;


    virtual bool isValid() const = 0;


    virtual void updateExtents()
    {
      // NOP by default
    }


    virtual bool setSubsetString( const QString &subset, bool updateFeatureCount = true )
    {
      // NOP by default
      Q_UNUSED( subset )
      Q_UNUSED( updateFeatureCount )
      return false;
    }


    virtual bool supportsSubsetString() const { return false; }

    virtual QString subsetString() const
    {
      return QString();
    }


    virtual QStringList subLayers() const
    {
      return QStringList();  // Empty
    }

    static QString SUBLAYER_SEPARATOR;

    virtual QStringList subLayerStyles() const
    {
      return QStringList();  // Empty
    }


    virtual uint subLayerCount() const
    {
      return 0;
    }


    virtual void setLayerOrder( const QStringList &layers )
    {
      //prevent unused var warnings
      if ( layers.count() < 1 )
      {
        return;
      }
      // NOOP
    }


    virtual void setSubLayerVisibility( const QString &name, bool vis )
    {
      //prevent unused var warnings
      if ( name.isEmpty() || !vis )
      {
        return;
      }
      // NOOP
    }


    virtual QString name() const = 0;


    virtual QString description() const = 0;


    virtual QString fileVectorFilters() const
    {
      return QString();
    }


    virtual QString fileRasterFilters() const
    {
      return QString();
    }

    virtual void reloadData() {}

    virtual QDateTime timestamp() const { return mTimestamp; }

    virtual QDateTime dataTimestamp() const { return QDateTime(); }

    virtual QgsError error() const { return mError; }

    virtual void invalidateConnections( const QString &connection ) { Q_UNUSED( connection ) }

    virtual bool enterUpdateMode() { return true; }

    virtual bool leaveUpdateMode() { return true; }

    void setProviderProperty( ProviderProperty property, const QVariant &value );

    void setProviderProperty( int property, const QVariant &value ); // SIP_SKIP

    QVariant providerProperty( ProviderProperty property, const QVariant &defaultValue = QVariant() ) const;

    QVariant providerProperty( int property, const QVariant &defaultValue ) const; // SIP_SKIP

    virtual void setListening( bool isListening );

#ifndef SIP_RUN

    struct PreviewContext
    {
      double lastRenderingTimeMs = -1;

      double maxRenderingTimeMs = MAXIMUM_LAYER_PREVIEW_TIME_MS;
    };
#endif

    virtual bool renderInPreview( const QgsDataProvider::PreviewContext &context ); // SIP_SKIP

    virtual QgsLayerMetadata layerMetadata() const { return QgsLayerMetadata(); }

    virtual bool writeLayerMetadata( const QgsLayerMetadata &metadata ) { Q_UNUSED( metadata ) return false; }

    QgsCoordinateTransformContext transformContext() const SIP_SKIP;

    virtual void setTransformContext( const QgsCoordinateTransformContext &transformContext ) SIP_SKIP;

  signals:

    void fullExtentCalculated();

    void dataChanged();

    void notify( const QString &msg );


  protected:

    QDateTime mTimestamp;

    QgsError mError;

    void appendError( const QgsErrorMessage &message ) { mError.append( message ); }

    void setError( const QgsError &error ) { mError = error;}

  private:

    QString mDataSourceURI;

    QMap< int, QVariant > mProviderProperties;

    QgsDataProvider::ProviderOptions mOptions;

    mutable QMutex mOptionsMutex;

};


#endif