mapnik/plugins/input/ogr/ogr_datasource.cpp

/*****************************************************************************
 * 
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2007 Artem Pavlenko
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 *****************************************************************************/
// $Id$

#include <iostream>
#include <fstream>
#include <stdexcept>

#include "ogr_datasource.hpp"
#include "ogr_featureset.hpp"
#include "ogr_index_featureset.hpp"

// mapnik
#include <mapnik/ptree_helpers.hpp>
#include <mapnik/geom_util.hpp>

// boost
#include <boost/algorithm/string.hpp>

using mapnik::datasource;
using mapnik::parameters;

DATASOURCE_PLUGIN(ogr_datasource)

using mapnik::box2d;
using mapnik::coord2d;
using mapnik::query;
using mapnik::featureset_ptr;
using mapnik::layer_descriptor;
using mapnik::attribute_descriptor;
using mapnik::datasource_exception;
using mapnik::filter_in_box;
using mapnik::filter_at_point;


ogr_datasource::ogr_datasource(parameters const& params, bool bind)
   : datasource(params),
     extent_(),
     type_(datasource::Vector),
     desc_(*params.get<std::string>("type"), *params.get<std::string>("encoding","utf-8")),
     indexed_(false)
{
   boost::optional<std::string> file = params.get<std::string>("file");
   boost::optional<std::string> string = params.get<std::string>("string");
   if (!file && !string) throw datasource_exception("missing <file> or <string> parameter");

   multiple_geometries_ = *params.get<mapnik::boolean>("multiple_geometries",false);

   if (string)
   {
       dataset_name_ = *string;
   }
   else
   {
       boost::optional<std::string> base = params.get<std::string>("base");
       if (base)
          dataset_name_ = *base + "/" + *file;
       else
          dataset_name_ = *file;
   }
      
   if (bind)
   {
      this->bind();
   }
}

ogr_datasource::~ogr_datasource()
{
    if (is_bound_) 
    {
        OGRDataSource::DestroyDataSource (dataset_);
    }
}

void ogr_datasource::bind() const
{
   if (is_bound_) return;   

   // initialize ogr formats
   OGRRegisterAll();
    
   // open ogr driver   
   dataset_ = OGRSFDriverRegistrar::Open ((dataset_name_).c_str(), FALSE);
   if (!dataset_) 
   {
      std::string err = CPLGetLastErrorMsg();
      if( err.size() == 0 ) {
         throw datasource_exception("OGR Plugin: connection failed: " + dataset_name_ + " was not found or is not a supported format");
      } else {
         throw datasource_exception("OGR Plugin: " + err);
      }
   } 

   // initialize layer
   
   boost::optional<std::string> layer_by_name = params_.get<std::string>("layer");
   boost::optional<unsigned> layer_by_index = params_.get<unsigned>("layer_by_index");
   
   if (layer_by_name && layer_by_index)
       throw datasource_exception("OGR Plugin: you can only select an ogr layer by name ('layer' parameter) or by number ('layer_by_index' parameter), do not supply both parameters" );

   if (layer_by_name) 
   {
       layerName_ = *layer_by_name;  
       layer_ = dataset_->GetLayerByName (layerName_.c_str());
   }
   else if (layer_by_index)
   { 
       unsigned num_layers = dataset_->GetLayerCount();
       if (*layer_by_index >= num_layers)
       {
           std::ostringstream s;
           s << "OGR Plugin: only ";
           s << num_layers;
           s << " layer(s) exist, cannot find layer by index '" << *layer_by_index << "'";
       
           throw datasource_exception(s.str());
       }
       OGRLayer  *ogr_layer = dataset_->GetLayer(*layer_by_index);
       if (ogr_layer)
       {
           OGRFeatureDefn* def = ogr_layer->GetLayerDefn();
           if (def != 0) { 
              layerName_ = def->GetName();
              layer_ = ogr_layer;
           }
       }
   }
   else
   {
      std::ostringstream s;
      s << "OGR Plugin: missing <layer> or <layer_by_index> parameter, available layers are: ";
      unsigned num_layers = dataset_->GetLayerCount();
      bool found = false;
      for (unsigned i = 0; i < num_layers; ++i )
      {
         OGRLayer  *ogr_layer = dataset_->GetLayer(i);
         OGRFeatureDefn* def = ogr_layer->GetLayerDefn();
         if (def != 0) { 
            found = true;
            s << " '" << def->GetName() << "' ";
         }
      }
      if (!found) {
          s << "None (no layers were found in dataset)";
      }
      throw datasource_exception(s.str());
   }

   if (!layer_)
   {
       std::string s("OGR Plugin: ");
       if (layer_by_name) s += "cannot find layer by name '" + *layer_by_name;
       else if (layer_by_index) s += "cannot find layer by index number '" + *layer_by_index;
       s += "' in dataset '" + dataset_name_ + "'";
       throw datasource_exception(s);
   }
   
   // initialize envelope
   OGREnvelope envelope;
   layer_->GetExtent (&envelope);
   extent_.init (envelope.MinX, envelope.MinY, envelope.MaxX, envelope.MaxY);

   // scan for index file
   // TODO - layer names don't match dataset name, so this will break for
   // any layer types of ogr than shapefiles, etc
   // fix here and in ogrindex
   size_t breakpoint = dataset_name_.find_last_of (".");
   if (breakpoint == std::string::npos) breakpoint = dataset_name_.length();
   index_name_ = dataset_name_.substr(0, breakpoint) + ".ogrindex";
   std::ifstream index_file (index_name_.c_str(), std::ios::in | std::ios::binary);
   if (index_file)
   {
      indexed_=true;
      index_file.close();
   }
   // enable this warning once the ogrindex tool is a bit more stable/mature
   //else
   /*{
      std::clog << "### Notice: no ogrindex file found for " + dataset_name_ + ", use the 'ogrindex' program to build an index for faster rendering\n";
   }*/

   // deal with attributes descriptions
   OGRFeatureDefn* def = layer_->GetLayerDefn ();
   if (def != 0)
   {
       int fld_count = def->GetFieldCount ();
       for (int i = 0; i < fld_count; i++)
       {
           OGRFieldDefn* fld = def->GetFieldDefn (i);

           std::string fld_name = fld->GetNameRef ();
           OGRFieldType type_oid = fld->GetType ();

           switch (type_oid)
           {
           case OFTInteger:
               desc_.add_descriptor(attribute_descriptor(fld_name,mapnik::Integer));
               break;

           case OFTReal:
               desc_.add_descriptor(attribute_descriptor(fld_name,mapnik::Double));
               break;
                   
           case OFTString:
           case OFTWideString: // deprecated
               desc_.add_descriptor(attribute_descriptor(fld_name,mapnik::String));
               break;
              
           case OFTBinary:
               desc_.add_descriptor(attribute_descriptor(fld_name,mapnik::Object));
               break;

           case OFTIntegerList:
           case OFTRealList:
           case OFTStringList:
           case OFTWideStringList: // deprecated !
#ifdef MAPNIK_DEBUG
               std::clog << "OGR Plugin: unhandled type_oid=" << type_oid << std::endl;
#endif
               break;

           case OFTDate:
           case OFTTime:
           case OFTDateTime: // unhandled !
#ifdef MAPNIK_DEBUG
               std::clog << "OGR Plugin: unhandled type_oid=" << type_oid << std::endl;
#endif
               desc_.add_descriptor(attribute_descriptor(fld_name,mapnik::Object));
               break;

           default: // unknown
#ifdef MAPNIK_DEBUG
               std::clog << "OGR Plugin: unknown type_oid=" << type_oid << std::endl;
#endif
               break;
           }
       }
   }
   
   is_bound_ = true;
}

std::string ogr_datasource::name()
{
   return "ogr";
}

int ogr_datasource::type() const
{
   return type_;
}

box2d<double> ogr_datasource::envelope() const
{
   if (!is_bound_) bind();
   return extent_;
}

layer_descriptor ogr_datasource::get_descriptor() const
{
   if (!is_bound_) bind();
   return desc_;
}

featureset_ptr ogr_datasource::features(query const& q) const
{
   if (!is_bound_) bind();
   
   if (dataset_ && layer_)
   {

        // TODO - actually filter fields!
        // http://trac.osgeo.org/gdal/wiki/rfc29_desired_fields
        // http://trac.osgeo.org/gdal/wiki/rfc28_sqlfunc
#if 0
        std::ostringstream s;
            
        s << "select ";
        std::set<std::string> const& props=q.property_names();
        std::set<std::string>::const_iterator pos=props.begin();
        std::set<std::string>::const_iterator end=props.end();
        while (pos != end)
        {
           s <<",\""<<*pos<<"\"";
           ++pos;
        }   
        s << " from " << layerName_ ;

        // execute existing SQL
        OGRLayer* layer = dataset_->ExecuteSQL (s.str(), poly);

        // layer must be freed
        dataset_->ReleaseResultSet (layer);
#endif

        if (indexed_)
        {
            filter_in_box filter(q.get_bbox());
            
            return featureset_ptr(new ogr_index_featureset<filter_in_box> (*dataset_,
                                                                           *layer_,
                                                                           filter,
                                                                           index_name_,
                                                                           desc_.get_encoding(),
                                                                           multiple_geometries_));
        }
        else
        {
            return featureset_ptr(new ogr_featureset (*dataset_,
                                                      *layer_,
                                                      q.get_bbox(),
                                                      desc_.get_encoding(),
                                                      multiple_geometries_));
        }
   }
   return featureset_ptr();
}

featureset_ptr ogr_datasource::features_at_point(coord2d const& pt) const
{
   if (!is_bound_) bind();
   
   if (dataset_ && layer_)
   {
        if (indexed_)
        {
            filter_at_point filter(pt);
            
            return featureset_ptr(new ogr_index_featureset<filter_at_point> (*dataset_,
                                                                             *layer_,
                                                                             filter,
                                                                             index_name_,
                                                                             desc_.get_encoding(),
                                                                             multiple_geometries_));
        }
        else
        {
            OGRPoint point;
            point.setX (pt.x);
            point.setY (pt.y);

            return featureset_ptr(new ogr_featureset (*dataset_,
                                                      *layer_,
                                                      point,
                                                      desc_.get_encoding(),
                                                      multiple_geometries_));
        }
   }
   return featureset_ptr();
}