mapnik/include/mapnik/datasource.hpp

/*****************************************************************************
 * 
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2006 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: datasource.hpp 43 2005-04-22 18:52:47Z pavlenko $

#ifndef DATASOURCE_HPP
#define DATASOURCE_HPP
// mapnik
#include <mapnik/config.hpp>
#include <mapnik/ctrans.hpp>
#include <mapnik/params.hpp>
#include <mapnik/feature.hpp>
#include <mapnik/query.hpp>
#include <mapnik/feature_layer_desc.hpp>
// boost
#include <boost/utility.hpp>
#include <boost/shared_ptr.hpp>
// stl
#include <map>
#include <string>

namespace mapnik {    
    typedef MAPNIK_DECL boost::shared_ptr<Feature> feature_ptr;
    
    struct MAPNIK_DECL Featureset
    {
        virtual feature_ptr next()=0;
        virtual ~Featureset() {};
    };
    
    typedef MAPNIK_DECL boost::shared_ptr<Featureset> featureset_ptr;
    
    class MAPNIK_DECL datasource_exception : public std::exception
    {
    private:
        std::string message_;
    public:
        datasource_exception(const std::string& message=std::string("no reason"))
            :message_(message) {}

        ~datasource_exception() throw() {}
        virtual const char* what() const throw()
        {
            return message_.c_str();
        }
    };
    
    class MAPNIK_DECL datasource : private boost::noncopyable
    {
    public:        
        enum datasource_t {
            Vector,
            Raster
        };
        
        datasource (parameters const& params)
            : params_(params) {}

        /*!
         * @brief Get the configuration parameters of the data source.
         *
         * These vary depending on the type of data source.
         *
         * @return The configuration parameters of the data source.
         */
        parameters const& params() const
        {
            return params_;
        }
        
        /*!
         * @brief Get the type of the datasource
         * @return The type of the datasource (Vector or Raster)
         */
        virtual int type() const=0;
        
        virtual featureset_ptr features(const query& q) const=0;
        virtual featureset_ptr features_at_point(coord2d const& pt) const=0;
        virtual Envelope<double> envelope() const=0;
        virtual layer_descriptor get_descriptor() const=0;
        virtual ~datasource() {};
    protected:
        parameters params_;
    };
    
    typedef std::string datasource_name();
    typedef datasource* create_ds(const parameters& params);
    typedef void destroy_ds(datasource *ds);

    
    class datasource_deleter
    {
    public:
        void operator() (datasource* ds)
        {
            delete ds;
        }
    };

    typedef boost::shared_ptr<datasource> datasource_ptr;
    
    
    #define DATASOURCE_PLUGIN(classname)                              \
        extern "C" MAPNIK_EXP std::string datasource_name()            \
        {                                                               \
            return classname::name();                                   \
        }                                                               \
        extern "C"  MAPNIK_EXP datasource* create(const parameters &params) \
        {                                                               \
            return new classname(params);                               \
        }                                                               \
        extern "C" MAPNIK_EXP void destroy(datasource *ds)             \
        {                                                               \
            delete ds;                                                  \
        }                                                               \
        //
}

#endif //DATASOURCE_HPP