175 lines
4.5 KiB
C++
175 lines
4.5 KiB
C++
/*****************************************************************************
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*
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* This file is part of Mapnik (c++ mapping toolkit)
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*
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* Copyright (C) 2024 Artem Pavlenko
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*****************************************************************************/
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#ifndef OGR_LAYER_PTR_HPP
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#define OGR_LAYER_PTR_HPP
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// mapnik
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#include <mapnik/debug.hpp>
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// stl
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#include <stdexcept>
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// gdal
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#include <ogrsf_frmts.h>
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using gdal_dataset_type = GDALDataset*;
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class ogr_layer_ptr
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{
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public:
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ogr_layer_ptr()
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: datasource_(nullptr)
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, layer_(nullptr)
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, owns_layer_(false)
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, is_valid_(false)
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{}
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~ogr_layer_ptr() { free_layer(); }
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void free_layer()
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{
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if (owns_layer_ && layer_ != nullptr && datasource_ != nullptr)
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{
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datasource_->ReleaseResultSet(layer_);
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}
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datasource_ = nullptr;
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layer_ = nullptr;
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layer_name_ = "";
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owns_layer_ = false;
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is_valid_ = false;
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}
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void layer_by_name(gdal_dataset_type const datasource, std::string const& layer_name)
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{
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free_layer();
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datasource_ = datasource;
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OGRLayer* ogr_layer = datasource_->GetLayerByName(layer_name.c_str());
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if (ogr_layer)
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{
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layer_name_ = layer_name;
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layer_ = ogr_layer;
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is_valid_ = true;
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MAPNIK_LOG_DEBUG(ogr) << "ogr_layer_ptr: layer_from_name layer=" << layer_name_;
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}
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#ifdef MAPNIK_LOG
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debug_print_last_error();
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#endif
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}
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void layer_by_index(gdal_dataset_type const datasource, int layer_index)
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{
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free_layer();
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datasource_ = datasource;
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OGRLayer* ogr_layer = datasource_->GetLayer(layer_index);
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if (ogr_layer)
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{
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OGRFeatureDefn* def = ogr_layer->GetLayerDefn();
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if (def != 0)
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{
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layer_ = ogr_layer;
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layer_name_ = def->GetName();
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is_valid_ = true;
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MAPNIK_LOG_DEBUG(ogr) << "ogr_layer_ptr: layer_from_index layer=" << layer_name_;
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}
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}
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#ifdef MAPNIK_LOG
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debug_print_last_error();
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#endif
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}
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void layer_by_sql(gdal_dataset_type const datasource, std::string const& layer_sql)
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{
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free_layer();
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datasource_ = datasource;
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owns_layer_ = true;
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// TODO - actually filter fields!
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// http://trac.osgeo.org/gdal/wiki/rfc29_desired_fields
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// http://trac.osgeo.org/gdal/wiki/rfc28_sqlfunc
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OGRGeometry* spatial_filter = nullptr;
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const char* sql_dialect = nullptr;
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OGRLayer* ogr_layer = datasource_->ExecuteSQL(layer_sql.c_str(), spatial_filter, sql_dialect);
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if (ogr_layer)
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{
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OGRFeatureDefn* def = ogr_layer->GetLayerDefn();
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if (def != 0)
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{
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layer_ = ogr_layer;
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layer_name_ = def->GetName();
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is_valid_ = true;
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MAPNIK_LOG_DEBUG(ogr) << "ogr_layer_ptr: layer_from_sql layer=" << layer_name_;
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}
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}
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#ifdef MAPNIK_LOG
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debug_print_last_error();
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#endif
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}
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std::string const& layer_name() const { return layer_name_; }
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OGRLayer* layer() const { return layer_; }
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bool is_valid() const { return is_valid_; }
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private:
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#ifdef MAPNIK_LOG
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void debug_print_last_error()
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{
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if (!is_valid_)
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{
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const std::string err = CPLGetLastErrorMsg();
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if (err.size() == 0)
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{
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MAPNIK_LOG_DEBUG(ogr) << "ogr_layer_ptr: Error getting layer";
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}
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else
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{
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MAPNIK_LOG_DEBUG(ogr) << "ogr_layer_ptr: " << err;
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}
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}
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}
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#endif
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gdal_dataset_type datasource_;
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OGRLayer* layer_;
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std::string layer_name_;
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bool owns_layer_;
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bool is_valid_;
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};
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#endif // OGR_LAYER_PTR_HPP
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