C++ OGRLayer::StartTransaction方法代码示例

    MyOGRHandler(const std::string& filename) :
        m_data_source(NULL),
        m_layer_point(NULL),
        m_filter(true),
        m_tohstore() {
        OGRRegisterAll();

        OGRSFDriver* driver = OGRSFDriverRegistrar::GetRegistrar()->GetDriverByName("PostgreSQL");
        if (driver == NULL) {
            std::cerr << "PostgreSQL OGR driver not available.\n";
            exit(1);
        }

        // using COPY is much faster than INSERT
        CPLSetConfigOption("PG_USE_COPY", "YES");
        const char* options[] = { NULL };
        m_data_source = driver->CreateDataSource(filename.c_str(), const_cast<char**>(options));
        if (m_data_source == NULL) {
            std::cerr << "Database open failed.\n";
            exit(1);
        }

        // OGR can't create a table with hstore column, so we do it ourselves here
        OGRLayer* dummy = m_data_source->ExecuteSQL("CREATE TABLE nodes (id VARCHAR, tags hstore);", NULL, NULL);
        if (dummy) {
            m_data_source->ReleaseResultSet(dummy);
        }
        dummy = m_data_source->ExecuteSQL("SELECT AddGeometryColumn('nodes', 'geom', 4326, 'POINT', 2);", NULL, NULL);
        if (dummy) {
            m_data_source->ReleaseResultSet(dummy);
        }

        m_layer_point = m_data_source->GetLayerByName("nodes");
        if (!m_layer_point) {
            std::cerr << "Something went wrong setting up the 'nodes' layer.\n";
            exit(1);
        }

        // using transactions makes this much faster than without
        m_layer_point->StartTransaction();

        m_filter.add(false, "created_by");
        m_filter.add(false, "odbl");
    }

    MyOGRHandler(const std::string& driver_name, const std::string& filename) {

        OGRRegisterAll();

        OGRSFDriver* driver = OGRSFDriverRegistrar::GetRegistrar()->GetDriverByName(driver_name.c_str());
        if (!driver) {
            std::cerr << driver_name << " driver not available.\n";
            exit(1);
        }

        CPLSetConfigOption("OGR_SQLITE_SYNCHRONOUS", "FALSE");
        const char* options[] = { "SPATIALITE=TRUE", nullptr };
        m_data_source = driver->CreateDataSource(filename.c_str(), const_cast<char**>(options));
        if (!m_data_source) {
            std::cerr << "Creation of output file failed.\n";
            exit(1);
        }

        OGRSpatialReference sparef;
        sparef.importFromProj4(m_factory.proj_string().c_str());

        m_layer_point = m_data_source->CreateLayer("postboxes", &sparef, wkbPoint, nullptr);
        if (!m_layer_point) {
            std::cerr << "Layer creation failed.\n";
            exit(1);
        }

        OGRFieldDefn layer_point_field_id("id", OFTReal);
        layer_point_field_id.SetWidth(10);

        if (m_layer_point->CreateField(&layer_point_field_id) != OGRERR_NONE) {
            std::cerr << "Creating id field failed.\n";
            exit(1);
        }

        OGRFieldDefn layer_point_field_operator("operator", OFTString);
        layer_point_field_operator.SetWidth(30);

        if (m_layer_point->CreateField(&layer_point_field_operator) != OGRERR_NONE) {
            std::cerr << "Creating operator field failed.\n";
            exit(1);
        }

        /* Transactions might make things faster, then again they might not.
           Feel free to experiment and benchmark and report back. */
        m_layer_point->StartTransaction();

        m_layer_linestring = m_data_source->CreateLayer("roads", &sparef, wkbLineString, nullptr);
        if (!m_layer_linestring) {
            std::cerr << "Layer creation failed.\n";
            exit(1);
        }

        OGRFieldDefn layer_linestring_field_id("id", OFTReal);
        layer_linestring_field_id.SetWidth(10);

        if (m_layer_linestring->CreateField(&layer_linestring_field_id) != OGRERR_NONE) {
            std::cerr << "Creating id field failed.\n";
            exit(1);
        }

        OGRFieldDefn layer_linestring_field_type("type", OFTString);
        layer_linestring_field_type.SetWidth(30);

        if (m_layer_linestring->CreateField(&layer_linestring_field_type) != OGRERR_NONE) {
            std::cerr << "Creating type field failed.\n";
            exit(1);
        }

        m_layer_linestring->StartTransaction();

        m_layer_polygon = m_data_source->CreateLayer("buildings", &sparef, wkbMultiPolygon, nullptr);
        if (!m_layer_polygon) {
            std::cerr << "Layer creation failed.\n";
            exit(1);
        }

        OGRFieldDefn layer_polygon_field_id("id", OFTInteger);
        layer_polygon_field_id.SetWidth(10);

        if (m_layer_polygon->CreateField(&layer_polygon_field_id) != OGRERR_NONE) {
            std::cerr << "Creating id field failed.\n";
            exit(1);
        }

        OGRFieldDefn layer_polygon_field_type("type", OFTString);
        layer_polygon_field_type.SetWidth(30);

        if (m_layer_polygon->CreateField(&layer_polygon_field_type) != OGRERR_NONE) {
            std::cerr << "Creating type field failed.\n";
            exit(1);
        }

        m_layer_polygon->StartTransaction();
    }

//.........这里部分代码省略.........
        
        if( poFeature == NULL )
            break;

        CPLErrorReset();
        poDstFeature = OGRFeature::CreateFeature( poDstLayer->GetLayerDefn() );

        if( poDstFeature->SetFrom( poFeature, TRUE ) != OGRERR_NONE )
        {
            delete poFeature;
            CPLError( CE_Failure, CPLE_AppDefined,
                      "Unable to translate feature %ld from layer %s.\n",
                      poFeature->GetFID(), poSrcDefn->GetName() );
            return poDstLayer;
        }

        poDstFeature->SetFID( poFeature->GetFID() );

        OGRFeature::DestroyFeature( poFeature );

        CPLErrorReset();
        if( poDstLayer->CreateFeature( poDstFeature ) != OGRERR_NONE )
        {
            OGRFeature::DestroyFeature( poDstFeature );
            return poDstLayer;
        }

        OGRFeature::DestroyFeature( poDstFeature );
      }
    }
    else
    {
      int i, bStopTransfer = FALSE, bStopTransaction = FALSE;
      int nFeatCount = 0; // Number of features in the temporary array
      int nFeaturesToAdd = 0;
      while( !bStopTransfer )
      {
        OGRFeature **papoDstFeature =
            (OGRFeature **)CPLCalloc(sizeof(OGRFeature *), nGroupTransactions);

/* -------------------------------------------------------------------- */
/*      Fill the array with features                                    */
/* -------------------------------------------------------------------- */
        for( nFeatCount = 0; nFeatCount < nGroupTransactions; nFeatCount++ )
        {
            poFeature = poSrcLayer->GetNextFeature();

            if( poFeature == NULL )
            {
                bStopTransfer = 1;
                break;
            }

            CPLErrorReset();
            papoDstFeature[nFeatCount] =
                        OGRFeature::CreateFeature( poDstLayer->GetLayerDefn() );

            if( papoDstFeature[nFeatCount]->SetFrom( poFeature, TRUE ) != OGRERR_NONE )
            {
                OGRFeature::DestroyFeature( poFeature );
                CPLError( CE_Failure, CPLE_AppDefined,
                          "Unable to translate feature %ld from layer %s.\n",
                          poFeature->GetFID(), poSrcDefn->GetName() );
                bStopTransfer = TRUE;
                break;
            }

            papoDstFeature[nFeatCount]->SetFID( poFeature->GetFID() );

            OGRFeature::DestroyFeature( poFeature );
        }
        nFeaturesToAdd = nFeatCount;

        CPLErrorReset();
        bStopTransaction = FALSE;
        while( !bStopTransaction )
        {
            bStopTransaction = TRUE;
            poDstLayer->StartTransaction();
            for( i = 0; i < nFeaturesToAdd; i++ )
            {
                if( poDstLayer->CreateFeature( papoDstFeature[i] ) != OGRERR_NONE )
                {
                    nFeaturesToAdd = i;
                    bStopTransfer = TRUE;
                    bStopTransaction = FALSE;
                }
            }
            if( bStopTransaction )
                poDstLayer->CommitTransaction();
            else
                poDstLayer->RollbackTransaction();
        }

        for( i = 0; i < nFeatCount; i++ )
            OGRFeature::DestroyFeature( papoDstFeature[i] );
      }
    }
    return poDstLayer;
}