qgsprovidermetadata.h

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/***************************************************************************
                    qgsprovidermetadata.h  -  Metadata class for
                    describing a data provider.
                             -------------------
    begin                : Sat Jan 10 2004
    copyright            : (C) 2004 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 QGSPROVIDERMETADATA_H
#define QGSPROVIDERMETADATA_H


#include <QString>
#include <QVariantMap>
#include <QMap>
#include <QList>
#include <memory>
#include <QPair>

#include "qgis_sip.h"
#include "qgsdataprovider.h"
#include "qgis_core.h"
#include <functional>
#include "qgsvectorlayerexporter.h"
#include "qgsabstractproviderconnection.h"
#include "qgsabstractdatabaseproviderconnection.h"
#include "qgsfields.h"
#include "qgsexception.h"

class QgsDataItem;
class QgsDataItemProvider;
class QgsTransaction;

class QgsRasterDataProvider;


class CORE_EXPORT QgsProviderMetadata
{
  public:

    SIP_SKIP typedef std::function < QgsDataProvider*( const QString &, const QgsDataProvider::ProviderOptions & ) > CreateDataProviderFunction;

    QgsProviderMetadata( const QString &key, const QString &description, const QString &library = QString() );

    SIP_SKIP Q_DECL_DEPRECATED QgsProviderMetadata( const QString &key, const QString &description, const QgsProviderMetadata::CreateDataProviderFunction &createFunc );

    virtual ~QgsProviderMetadata();

    QString key() const;

    QString description() const;

    Q_DECL_DEPRECATED QString library() const SIP_DEPRECATED;

    SIP_SKIP Q_DECL_DEPRECATED CreateDataProviderFunction createFunction() const;

    virtual void initProvider();

    virtual void cleanupProvider();

    enum class FilterType
    {
      FilterVector = 1,
      FilterRaster,
      FilterMesh,
      FilterMeshDataset
    };

    virtual QString filters( FilterType type );

    virtual QgsDataProvider *createProvider( const QString &uri, const QgsDataProvider::ProviderOptions &options ) SIP_FACTORY;

#ifndef SIP_RUN

    virtual QgsVectorLayerExporter::ExportError createEmptyLayer( const QString &uri,
        const QgsFields &fields,
        QgsWkbTypes::Type wkbType,
        const QgsCoordinateReferenceSystem &srs,
        bool overwrite,
        QMap<int, int> &oldToNewAttrIdxMap,
        QString &errorMessage,
        const QMap<QString, QVariant> *options );
#endif

    virtual QgsRasterDataProvider *createRasterDataProvider(
      const QString &uri,
      const QString &format,
      int nBands,
      Qgis::DataType type,
      int width,
      int height,
      double *geoTransform,
      const QgsCoordinateReferenceSystem &crs,
      const QStringList &createOptions = QStringList() ) SIP_FACTORY;

    virtual QList<QPair<QString, QString> > pyramidResamplingMethods();

    virtual QVariantMap decodeUri( const QString &uri );

    virtual QList< QgsDataItemProvider * > dataItemProviders() const SIP_FACTORY;

    virtual int listStyles( const QString &uri, QStringList &ids, QStringList &names,
                            QStringList &descriptions, QString &errCause );

    virtual QString getStyleById( const QString &uri, QString styleId, QString &errCause );

    virtual bool deleteStyleById( const QString &uri, QString styleId, QString &errCause );

    virtual bool saveStyle( const QString &uri, const QString &qmlStyle, const QString &sldStyle,
                            const QString &styleName, const QString &styleDescription,
                            const QString &uiFileContent, bool useAsDefault, QString &errCause );

    virtual QString loadStyle( const QString &uri, QString &errCause );

    virtual bool createDb( const QString &dbPath, QString &errCause );

    virtual QgsTransaction *createTransaction( const QString &connString ) SIP_FACTORY;

    virtual QMap<QString, QgsAbstractProviderConnection *> connections( bool cached = true ) SIP_THROW( QgsProviderConnectionException );

    QMap<QString, QgsAbstractDatabaseProviderConnection *> dbConnections( bool cached = true ) SIP_THROW( QgsProviderConnectionException );

    QgsAbstractProviderConnection *findConnection( const QString &name, bool cached = true ) SIP_THROW( QgsProviderConnectionException );

#ifndef SIP_RUN

    template <typename T> QMap<QString, T *>connections( bool cached = true );


#endif

    virtual QgsAbstractProviderConnection *createConnection( const QString &uri, const QVariantMap &configuration ) SIP_FACTORY;

    virtual QgsAbstractProviderConnection *createConnection( const QString &name );

    virtual void deleteConnection( const QString &name ) SIP_THROW( QgsProviderConnectionException );

    virtual void saveConnection( const QgsAbstractProviderConnection *connection, const QString &name );

  protected:

#ifndef SIP_RUN

    // Common functionality for connections management, to be moved into the class
    // when all the providers are ready
    // T_provider_conn: subclass of QgsAbstractProviderConnection,
    // T_conn: provider connection class (such as QgsOgrDbConnection or QgsPostgresConn)
    // TODO QGIS4: remove all old provider conn classes and move functionality into QgsAbstractProviderConnection subclasses
    template <class T_provider_conn, class T_conn> QMap<QString, QgsAbstractProviderConnection *> connectionsProtected( bool cached = true )
    {
      if ( ! cached || mProviderConnections.isEmpty() )
      {
        qDeleteAll( mProviderConnections );
        mProviderConnections.clear();
        const auto connNames { T_conn::connectionList() };
        for ( const auto &cname : connNames )
        {
          mProviderConnections.insert( cname, new T_provider_conn( cname ) );
        }
      }
      return mProviderConnections;
    }

    template <class T_provider_conn> void deleteConnectionProtected( const QString &name )
    {
      T_provider_conn conn( name );
      conn.remove( name );
      mProviderConnections.clear();
    }
    virtual void saveConnectionProtected( const QgsAbstractProviderConnection *connection, const QString &name );
    QMap<QString, QgsAbstractProviderConnection *> mProviderConnections;

#endif

  private:

    QString mKey;

    QString mDescription;

    QString mLibrary;

    CreateDataProviderFunction mCreateFunction = nullptr;

};

#endif //QGSPROVIDERMETADATA_H