C++ mapnik::datasource_exception方法代码示例

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

#ifdef MAPNIK_STATS
    mapnik::progress_timer __stats__(std::clog, "occi_datasource::bind");
#endif

    // connect to environment
    if (use_connection_pool_)
    {
        try
        {
            Environment* env = occi_environment::get_environment();

            pool_ = env->createStatelessConnectionPool(
                *params_.get<std::string>("user"),
                *params_.get<std::string>("password"),
                *params_.get<std::string>("host"),
                *params_.get<int>("max_size", 5),
                *params_.get<int>("initial_size", 1),
                1,
                StatelessConnectionPool::HOMOGENEOUS);
        }
        catch (SQLException& ex)
        {
            throw datasource_exception("OCCI Plugin: " + ex.getMessage());
        }
    }
    else
    {
        try
        {
            Environment* env = occi_environment::get_environment();

            conn_ = env->createConnection(
                *params_.get<std::string>("user"),
                *params_.get<std::string>("password"),
                *params_.get<std::string>("host"));
        }
        catch (SQLException& ex)
        {
            throw datasource_exception("OCCI Plugin: " + ex.getMessage());
        }
    }

    // extract real table name
    table_name_ = mapnik::sql_utils::table_from_sql(table_);

    // get SRID and/or GEOMETRY_FIELD from metadata table only if we need to
    if (! srid_initialized_ || geometry_field_ == "")
    {
#ifdef MAPNIK_STATS
        mapnik::progress_timer __stats__(std::clog, "occi_datasource::get_srid_and_geometry_field");
#endif

        std::ostringstream s;
        s << "SELECT srid, column_name FROM " << METADATA_TABLE << " WHERE";
        s << " LOWER(table_name) = LOWER('" << table_name_ << "')";

        if (geometry_field_ != "")
        {
            s << " AND LOWER(column_name) = LOWER('" << geometry_field_ << "')";
        }

        MAPNIK_LOG_DEBUG(occi) << "occi_datasource: " << s.str();

        try
        {
            occi_connection_ptr conn;
            if (use_connection_pool_) conn.set_pool(pool_);
            else                      conn.set_connection(conn_, false);

            ResultSet* rs = conn.execute_query(s.str());
            if (rs && rs->next ())
            {
                if (! srid_initialized_)
                {
                    srid_ = rs->getInt(1);
                    srid_initialized_ = true;
                }

                if (geometry_field_ == "")
                {
                    geometry_field_ = rs->getString(2);
                }
            }
        }
        catch (SQLException& ex)
        {
            throw datasource_exception("OCCI Plugin: " + ex.getMessage());
        }
    }

    // get columns description
    {
#ifdef MAPNIK_STATS
        mapnik::progress_timer __stats__(std::clog, "occi_datasource::get_column_description");
#endif

//.........这里部分代码省略.........

sqlite_datasource::sqlite_datasource(parameters const& params)
    : datasource(params),
      extent_(),
      extent_initialized_(false),
      type_(datasource::Vector),
      table_(*params.get<std::string>("table", "")),
      fields_(*params.get<std::string>("fields", "*")),
      metadata_(*params.get<std::string>("metadata", "")),
      geometry_table_(*params.get<std::string>("geometry_table", "")),
      geometry_field_(*params.get<std::string>("geometry_field", "")),
      index_table_(*params.get<std::string>("index_table", "")),
      key_field_(*params.get<std::string>("key_field", "")),
      row_offset_(*params.get<mapnik::value_integer>("row_offset", 0)),
      row_limit_(*params.get<mapnik::value_integer>("row_limit", 0)),
      intersects_token_("!intersects!"),
      desc_(*params.get<std::string>("type"), *params.get<std::string>("encoding", "utf-8")),
      format_(mapnik::wkbAuto)
{
    /* TODO
       - throw if no primary key but spatial index is present?
       - remove auto-indexing
       - if spatialite - leverage more of the metadata for geometry type detection
    */

#ifdef MAPNIK_STATS
    mapnik::progress_timer __stats__(std::clog, "sqlite_datasource::init");
#endif

    boost::optional<std::string> file = params.get<std::string>("file");
    if (! file) throw datasource_exception("Sqlite Plugin: missing <file> parameter");

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

    if ((dataset_name_.compare(":memory:") != 0) && (!mapnik::util::exists(dataset_name_)))
    {
        throw datasource_exception("Sqlite Plugin: " + dataset_name_ + " does not exist");
    }

    use_spatial_index_ = *params.get<mapnik::boolean>("use_spatial_index", true);

    // TODO - remove this option once all datasources have an indexing api
    bool auto_index = *params.get<mapnik::boolean>("auto_index", true);

    boost::optional<std::string> ext  = params.get<std::string>("extent");
    if (ext) extent_initialized_ = extent_.from_string(*ext);

    boost::optional<std::string> wkb = params.get<std::string>("wkb_format");
    if (wkb)
    {
        if (*wkb == "spatialite")
        {
            format_ = mapnik::wkbSpatiaLite;
        }
        else if (*wkb == "generic")
        {
            format_ = mapnik::wkbGeneric;
        }
        else
        {
            format_ = mapnik::wkbAuto;
        }
    }

    // Populate init_statements_
    //   1. Build attach database statements from the "attachdb" parameter
    //   2. Add explicit init statements from "initdb" parameter
    // Note that we do some extra work to make sure that any attached
    // databases are relative to directory containing dataset_name_.  Sqlite
    // will default to attaching from cwd.  Typicaly usage means that the
    // map loader will produce full paths here.
    boost::optional<std::string> attachdb = params.get<std::string>("attachdb");
    if (attachdb)
    {
        parse_attachdb(*attachdb);
    }

    boost::optional<std::string> initdb = params.get<std::string>("initdb");
    if (initdb)
    {
        init_statements_.push_back(*initdb);
    }

    // now actually create the connection and start executing setup sql
    dataset_ = std::make_shared<sqlite_connection>(dataset_name_);

    boost::optional<mapnik::value_integer> table_by_index = params.get<mapnik::value_integer>("table_by_index");

    int passed_parameters = 0;
    passed_parameters += params.get<std::string>("table") ? 1 : 0;
    passed_parameters += table_by_index ? 1 : 0;

    if (passed_parameters > 1)
    {
        throw datasource_exception("SQLite Plugin: you can only select an by name "
                                   "('table' parameter), by number ('table_by_index' parameter), "
                                   "do not supply 2 or more of them at the same time" );
//.........这里部分代码省略.........

raster_datasource::raster_datasource(parameters const& params)
: datasource(params),
    desc_(*params.get<std::string>("type"), "utf-8"),
    extent_initialized_(false)
{
    MAPNIK_LOG_DEBUG(raster) << "raster_datasource: Initializing...";

    boost::optional<std::string> file = params.get<std::string>("file");
    if (! file) throw datasource_exception("Raster Plugin: missing <file> parameter ");

    boost::optional<std::string> base = params.get<std::string>("base");
    if (base)
        filename_ = *base + "/" + *file;
    else
        filename_ = *file;

    multi_tiles_ = *params.get<mapnik::boolean>("multi", false);
    tile_size_ = *params.get<int>("tile_size", 256);
    tile_stride_ = *params.get<int>("tile_stride", 1);

    boost::optional<std::string> format_from_filename = mapnik::type_from_filename(*file);
    format_ = *params.get<std::string>("format",format_from_filename?(*format_from_filename) : "tiff");

    boost::optional<double> lox = params.get<double>("lox");
    boost::optional<double> loy = params.get<double>("loy");
    boost::optional<double> hix = params.get<double>("hix");
    boost::optional<double> hiy = params.get<double>("hiy");

    boost::optional<std::string> ext = params.get<std::string>("extent");

    if (lox && loy && hix && hiy)
    {
        extent_.init(*lox, *loy, *hix, *hiy);
        extent_initialized_ = true;
    }
    else if (ext)
    {
        extent_initialized_ = extent_.from_string(*ext);
    }

    if (! extent_initialized_)
    {
        throw datasource_exception("Raster Plugin: valid <extent> or <lox> <loy> <hix> <hiy> are required");
    }

    if (multi_tiles_)
    {
        boost::optional<int> x_width = params.get<int>("x_width");
        boost::optional<int> y_width = params.get<int>("y_width");

        if (! x_width)
        {
            throw datasource_exception("Raster Plugin: x-width parameter not supplied for multi-tiled data source.");
        }

        if (! y_width)
        {
            throw datasource_exception("Raster Plugin: y-width parameter not supplied for multi-tiled data source.");
        }

        width_ = x_width.get() * tile_size_;
        height_ = y_width.get() * tile_size_;
    }
    else
    {
        if (!mapnik::util::exists(filename_))
        {
            throw datasource_exception("Raster Plugin: " + filename_ + " does not exist");
        }

        try
        {
            std::auto_ptr<image_reader> reader(mapnik::get_image_reader(filename_, format_));
            if (reader.get())
            {
                width_ = reader->width();
                height_ = reader->height();
            }
        }
        catch (mapnik::image_reader_exception const& ex)
        {
            throw datasource_exception("Raster Plugin: image reader exception: " + std::string(ex.what()));
        }
        catch (std::exception const& ex)
        {
            throw datasource_exception("Raster Plugin: " + std::string(ex.what()));
        }
        catch (...)
        {
            throw datasource_exception("Raster Plugin: image reader unknown exception caught");
        }
    }

    MAPNIK_LOG_DEBUG(raster) << "raster_datasource: Raster size=" << width_ << "," << height_;

}

void spatialite_datasource::bind() const
{
    if (is_bound_) return;
    
    boost::optional<std::string> file = params_.get<std::string>("file");
    if (!file) throw datasource_exception("Spatialite Plugin: missing <file> parameter");
    
    boost::optional<std::string> key_field_name = params_.get<std::string>("key_field");
    if (key_field_name) {
        std::string const& key_field_string = *key_field_name;
        if (key_field_string.empty()) {
            key_field_ = "rowid";
        } else {
            key_field_ = key_field_string;
        }
    }
    else
    {
        key_field_ = "rowid";
    }
    
    boost::optional<std::string> wkb = params_.get<std::string>("wkb_format");
    if (wkb)
    {
        if (*wkb == "spatialite")
            format_ = mapnik::wkbSpatiaLite;  
    }

    multiple_geometries_ = *params_.get<mapnik::boolean>("multiple_geometries",false);
    use_spatial_index_ = *params_.get<mapnik::boolean>("use_spatial_index",true);
    has_spatial_index_ = false;
    using_subquery_ = false;

    boost::optional<std::string> ext  = params_.get<std::string>("extent");
    if (ext) extent_initialized_ = extent_.from_string(*ext);

    boost::optional<std::string> base = params_.get<std::string>("base");
    if (base)
        dataset_name_ = *base + "/" + *file;
    else
        dataset_name_ = *file;

    // Populate init_statements_
    //   1. Build attach database statements from the "attachdb" parameter
    //   2. Add explicit init statements from "initdb" parameter
    // Note that we do some extra work to make sure that any attached
    // databases are relative to directory containing dataset_name_.  Sqlite
    // will default to attaching from cwd.  Typicaly usage means that the
    // map loader will produce full paths here.
    boost::optional<std::string> attachdb = params_.get<std::string>("attachdb");
    if (attachdb) {
       parse_attachdb(*attachdb);
    }
    
    boost::optional<std::string> initdb = params_.get<std::string>("initdb");
    if (initdb) {
       init_statements_.push_back(*initdb);
    }

    if (!boost::filesystem::exists(dataset_name_))
        throw datasource_exception("Spatialite Plugin: " + dataset_name_ + " does not exist");
          
    dataset_ = new sqlite_connection (dataset_name_);

    // Execute init_statements_
    for (std::vector<std::string>::const_iterator iter=init_statements_.begin(); iter!=init_statements_.end(); ++iter)
    {
#ifdef MAPNIK_DEBUG
        std::clog << "Spatialite Plugin: Execute init sql: " << *iter << std::endl;
#endif
        dataset_->execute(*iter);
    }
    
    if(geometry_table_.empty())
    {
        geometry_table_ = mapnik::table_from_sql(table_);
    }

    // should we deduce column names and types using PRAGMA?
    bool use_pragma_table_info = true;
    
    if (table_ != geometry_table_)
    {
        // if 'table_' is a subquery then we try to deduce names
        // and types from the first row returned from that query
        using_subquery_ = true;
        use_pragma_table_info = false;
    }

    if (!use_pragma_table_info)
    {
        std::ostringstream s;
        s << "SELECT " << fields_ << " FROM (" << table_ << ") LIMIT 1";

        boost::scoped_ptr<sqlite_resultset> rs(dataset_->execute_query(s.str()));
        if (rs->is_valid() && rs->step_next())
        {
            for (int i = 0; i < rs->column_count (); ++i)
            {
               const int type_oid = rs->column_type (i);
//.........这里部分代码省略.........

shape_datasource::shape_datasource(parameters const& params)
    : datasource (params),
      type_(datasource::Vector),
      file_length_(0),
      indexed_(false),
      row_limit_(*params.get<mapnik::value_integer>("row_limit",0)),
      desc_(shape_datasource::name(), *params.get<std::string>("encoding","utf-8"))
{
#ifdef MAPNIK_STATS
    mapnik::progress_timer __stats__(std::clog, "shape_datasource::init");
#endif
    boost::optional<std::string> file = params.get<std::string>("file");
    if (!file) throw datasource_exception("Shape Plugin: missing <file> parameter");

    boost::optional<std::string> base = params.get<std::string>("base");
    if (base)
        shape_name_ = *base + "/" + *file;
    else
        shape_name_ = *file;

    boost::algorithm::ireplace_last(shape_name_,".shp","");
    if (!mapnik::util::exists(shape_name_ + ".shp"))
    {
        throw datasource_exception("Shape Plugin: shapefile '" + shape_name_ + ".shp' does not exist");
    }
    if (mapnik::util::is_directory(shape_name_ + ".shp"))
    {
        throw datasource_exception("Shape Plugin: shapefile '" + shape_name_ + ".shp' appears to be a directory not a file");
    }
    if (!mapnik::util::exists(shape_name_ + ".dbf"))
    {
        throw datasource_exception("Shape Plugin: shapefile '" + shape_name_ + ".dbf' does not exist");
    }

    try
    {
#ifdef MAPNIK_STATS
        mapnik::progress_timer __stats2__(std::clog, "shape_datasource::init(get_column_description)");
#endif

        std::unique_ptr<shape_io> shape_ref = std::make_unique<shape_io>(shape_name_);
        init(*shape_ref);
        for (int i=0;i<shape_ref->dbf().num_fields();++i)
        {
            field_descriptor const& fd=shape_ref->dbf().descriptor(i);
            std::string fld_name=fd.name_;
            switch (fd.type_)
            {
            case 'C': // character
            case 'D': // date
                desc_.add_descriptor(attribute_descriptor(fld_name, String));
                break;
            case 'L': // logical
                desc_.add_descriptor(attribute_descriptor(fld_name, Boolean));
                break;
            case 'N': // numeric
            case 'O': // double
            case 'F': // float
            {
                if (fd.dec_>0)
                {
                    desc_.add_descriptor(attribute_descriptor(fld_name,Double,false,8));
                }
                else
                {
                    desc_.add_descriptor(attribute_descriptor(fld_name,Integer,false,4));
                }
                break;
            }
            default:
                // I - long
                // G - ole
                // + - autoincrement
                // @ - timestamp
                // B - binary
                // l - long
                // M - memo
                MAPNIK_LOG_ERROR(shape) << "shape_datasource: Unknown type=" << fd.type_;
                break;
            }
        }
    }
    catch (datasource_exception const& ex)
    {
        MAPNIK_LOG_ERROR(shape) << "Shape Plugin: error processing field attributes, " << ex.what();
        throw;
    }
    catch (const std::exception& ex)
    {
        MAPNIK_LOG_ERROR(shape) << "Shape Plugin: error processing field attributes, " << ex.what();
        throw;
    }
    catch (...) // exception: pipe_select_interrupter: Too many open files
    {
        MAPNIK_LOG_ERROR(shape) << "Shape Plugin: error processing field attributes";
        throw;
    }

}

//.........这里部分代码省略.........

            MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Applying layer filter_factor=" << filter_factor_;
        }
        // otherwise respect symbolizer level factor applied to query, default of 1.0
        else
        {
            double sym_downsample_factor = q.get_filter_factor();
            im_width *= sym_downsample_factor;
            im_height *= sym_downsample_factor;
        }

        // case where we need to avoid upsampling so that the
        // image can be later scaled within raster_symbolizer
        if (im_width >= width || im_height >= height)
        {
            im_width = width;
            im_height = height;
        }

        if (im_width > 0 && im_height > 0)
        {
            mapnik::raster_ptr raster = boost::make_shared<mapnik::raster>(intersect, im_width, im_height);
            feature->set_raster(raster);
            mapnik::image_data_32 & image = raster->data_;
            image.set(0xffffffff);

            MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Image Size=(" << im_width << "," << im_height << ")";
            MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Reading band=" << band_;

            if (band_ > 0) // we are querying a single band
            {
                if (band_ > nbands_)
                {
                    throw datasource_exception((boost::format("GDAL Plugin: '%d' is an invalid band, dataset only has '%d' bands\n") % band_ % nbands_).str());
                }

                float* imageData = (float*)image.getBytes();
                GDALRasterBand * band = dataset_.GetRasterBand(band_);
                int hasNoData(0);
                double nodata(0);
                if (nodata_value_)
                {
                    hasNoData = 1;
                    nodata = *nodata_value_;
                }
                else
                {
                    nodata = band->GetNoDataValue(&hasNoData);
                }
                band->RasterIO(GF_Read, x_off, y_off, width, height,
                               imageData, image.width(), image.height(),
                               GDT_Float32, 0, 0);

                if (hasNoData)
                {
                    feature->put("NODATA",nodata);
                }
            }
            else // working with all bands
            {
                for (int i = 0; i < nbands_; ++i)
                {
                    GDALRasterBand * band = dataset_.GetRasterBand(i + 1);

#ifdef MAPNIK_LOG
                    get_overview_meta(band);

occi_datasource::occi_datasource(parameters const& params)
    : datasource (params),
      type_(datasource::Vector),
      fields_(*params.get<std::string>("fields", "*")),
      geometry_field_(*params.get<std::string>("geometry_field", "")),
      srid_initialized_(false),
      extent_initialized_(false),
      bbox_token_("!bbox!"),
      scale_denom_token_("!scale_denominator!"),
      pixel_width_token_("!pixel_width!"),
      pixel_height_token_("!pixel_height!"),
      desc_(occi_datasource::name(), *params.get<std::string>("encoding", "utf-8")),
      use_wkb_(*params.get<mapnik::boolean_type>("use_wkb", false)),
      row_limit_(*params.get<mapnik::value_integer>("row_limit", 0)),
      row_prefetch_(*params.get<mapnik::value_integer>("row_prefetch", 100)),
      pool_(0),
      conn_(0)
{
#ifdef MAPNIK_STATS
    mapnik::progress_timer __stats__(std::clog, "occi_datasource::init");
#endif

    if (! params.get<std::string>("user")) throw datasource_exception("OCCI Plugin: no <user> specified");
    if (! params.get<std::string>("password")) throw datasource_exception("OCCI Plugin: no <password> specified");
    if (! params.get<std::string>("host")) throw datasource_exception("OCCI Plugin: no <host> string specified");

    boost::optional<std::string> table = params.get<std::string>("table");
    if (! table)
    {
        throw datasource_exception("OCCI Plugin: no <table> parameter specified");
    }
    else
    {
        table_ = *table;
    }
    estimate_extent_ = *params.get<mapnik::boolean_type>("estimate_extent",false);
    use_spatial_index_ = *params.get<mapnik::boolean_type>("use_spatial_index",true);
    use_connection_pool_ = *params.get<mapnik::boolean_type>("use_connection_pool",true);

    boost::optional<std::string> ext = params.get<std::string>("extent");
    if (ext) extent_initialized_ = extent_.from_string(*ext);

    boost::optional<mapnik::value_integer> srid = params.get<mapnik::value_integer>("srid");
    if (srid)
    {
        srid_ = *srid;
        srid_initialized_ = true;
    }

    // connect to environment
    if (use_connection_pool_)
    {
        try
        {
            pool_ = occi_environment::instance().create_pool(
                        *params.get<std::string>("user"),
                        *params.get<std::string>("password"),
                        *params.get<std::string>("host"),
                        *params.get<mapnik::value_integer>("max_size", 5),
                        *params.get<mapnik::value_integer>("initial_size", 1),
                        1);
        }
        catch (SQLException& ex)
        {
            throw datasource_exception("OCCI Plugin: " + ex.getMessage());
        }
    }
    else
    {
        try
        {
            conn_ = occi_environment::instance().create_connection(
                        *params.get<std::string>("user"),
                        *params.get<std::string>("password"),
                        *params.get<std::string>("host"));
        }
        catch (SQLException& ex)
        {
            throw datasource_exception("OCCI Plugin: " + ex.getMessage());
        }
    }

    // extract real table name
    table_name_ = mapnik::sql_utils::table_from_sql(table_);

    // get SRID and/or GEOMETRY_FIELD from metadata table only if we need to
    if (! srid_initialized_ || geometry_field_ == "")
    {
#ifdef MAPNIK_STATS
        mapnik::progress_timer __stats__(std::clog, "occi_datasource::get_srid_and_geometry_field");
#endif

        std::ostringstream s;
        s << "SELECT srid, column_name FROM " << METADATA_TABLE << " WHERE";
        s << " LOWER(table_name) = LOWER('" << table_name_ << "')";

        if (geometry_field_ != "")
        {
            s << " AND LOWER(column_name) = LOWER('" << geometry_field_ << "')";
        }
//.........这里部分代码省略.........

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

    osm_data_ = NULL;
    std::string osm_filename = *params_.get<std::string>("file", "");
    std::string parser = *params_.get<std::string>("parser", "libxml2");
    std::string url = *params_.get<std::string>("url", "");
    std::string bbox = *params_.get<std::string>("bbox", "");

    bool do_process = false;

    // load the data
    // if we supplied a filename, load from file
    if (url != "" && bbox != "")
    {
        // otherwise if we supplied a url and a bounding box, load from the url
#ifdef MAPNIK_DEBUG
        std::clog << "Osm Plugin: loading_from_url: url=" << url << " bbox=" << bbox << std::endl;
#endif
        if ((osm_data_ = dataset_deliverer::load_from_url(url, bbox, parser)) == NULL)
        {
            throw datasource_exception("Error loading from URL");
        }

        do_process = true;
    }
    else if (osm_filename != "")
    {
        if ((osm_data_= dataset_deliverer::load_from_file(osm_filename, parser)) == NULL)
        {
            throw datasource_exception("Error loading from file");
        }

        do_process = true;
    }

    if (do_process == true)
    {
        osm_tag_types tagtypes;
        tagtypes.add_type("maxspeed", mapnik::Integer);
        tagtypes.add_type("z_order", mapnik::Integer);

        osm_data_->rewind();

        // Need code to get the attributes of all the data
        std::set<std::string> keys = osm_data_->get_keys();

        // Add the attributes to the datasource descriptor - assume they are
        // all of type String
        for (std::set<std::string>::iterator i = keys.begin(); i != keys.end(); i++)
        {
            desc_.add_descriptor(attribute_descriptor(*i, tagtypes.get_type(*i)));
        }

        // Get the bounds of the data and set extent_ accordingly
        bounds b = osm_data_->get_bounds();
        extent_ =  box2d<double>(b.w, b.s, b.e, b.n);
    }

    is_bound_ = true;
}

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

    // open geos driver
    initGEOS(geos_notice, geos_error);

    // parse the string into geometry
    geometry_.set_feature(GEOSGeomFromWKT(geometry_string_.c_str()));
    if (*geometry_ == NULL || ! GEOSisValid(*geometry_))
    {
        throw datasource_exception("GEOS Plugin: invalid <wkt> geometry specified");
    }

    // try to obtain the extent from the geometry itself
    if (! extent_initialized_)
    {
#ifdef MAPNIK_DEBUG
        clog << "GEOS Plugin: initializing extent from geometry" << endl;
#endif

        if (GEOSGeomTypeId(*geometry_) == GEOS_POINT)
        {
            double x, y;
            unsigned int size;

            const GEOSCoordSequence* cs = GEOSGeom_getCoordSeq(*geometry_);

            GEOSCoordSeq_getSize(cs, &size);
            GEOSCoordSeq_getX(cs, 0, &x);
            GEOSCoordSeq_getY(cs, 0, &y);
        
            extent_.init(x,y,x,y);
            extent_initialized_ = true;
        }
        else
        {
            geos_feature_ptr envelope (GEOSEnvelope(*geometry_));
            if (*envelope != NULL && GEOSisValid(*envelope))
            {
#ifdef MAPNIK_DEBUG
                char* wkt = GEOSGeomToWKT(*envelope);
                clog << "GEOS Plugin: getting coord sequence from: " << wkt << endl;
                GEOSFree(wkt);
#endif

                const GEOSGeometry* exterior = GEOSGetExteriorRing(*envelope);
                if (exterior != NULL && GEOSisValid(exterior))
                {
                    const GEOSCoordSequence* cs = GEOSGeom_getCoordSeq(exterior);
                    if (cs != NULL)
                    {
#ifdef MAPNIK_DEBUG
                        clog << "GEOS Plugin: iterating boundary points" << endl;
#endif

                        double x, y;
                        double minx = std::numeric_limits<float>::max(),
                               miny = std::numeric_limits<float>::max(),
                               maxx = -std::numeric_limits<float>::max(),
                               maxy = -std::numeric_limits<float>::max();
                        unsigned int num_points;

                        GEOSCoordSeq_getSize(cs, &num_points);

                        for (unsigned int i = 0; i < num_points; ++i)
                        {
                            GEOSCoordSeq_getX(cs, i, &x);
                            GEOSCoordSeq_getY(cs, i, &y);
                            
                            if (x < minx) minx = x;
                            if (x > maxx) maxx = x;
                            if (y < miny) miny = y;
                            if (y > maxy) maxy = y;
                        }

                        extent_.init(minx,miny,maxx,maxy);
                        extent_initialized_ = true;
                    }
                }
            }
        }
    }

    if (! extent_initialized_)
        throw datasource_exception("GEOS Plugin: cannot determine extent for <wkt> geometry");
   
    is_bound_ = true;
}

void ogr_datasource::init(mapnik::parameters const& params)
{
#ifdef MAPNIK_STATS
    mapnik::progress_timer __stats__(std::clog, "ogr_datasource::init");
#endif

    boost::optional<std::string> file = params.get<std::string>("file");
    boost::optional<std::string> string = params.get<std::string>("string");
    if (!string) string  = params.get<std::string>("inline");
    if (! file && ! string)
    {
        throw datasource_exception("missing <file> or <string> parameter");
    }

    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;
        }
    }

    std::string driver = *params.get<std::string>("driver","");

    if (! driver.empty())
    {
#if GDAL_VERSION_MAJOR >= 2
        unsigned int nOpenFlags = GDAL_OF_READONLY | GDAL_OF_VECTOR;
        const char* papszAllowedDrivers[] = { driver.c_str(), nullptr };
        dataset_ = reinterpret_cast<gdal_dataset_type>(GDALOpenEx(dataset_name_.c_str(),nOpenFlags,papszAllowedDrivers, nullptr, nullptr));
#else
        OGRSFDriver * ogr_driver = OGRSFDriverRegistrar::GetRegistrar()->GetDriverByName(driver.c_str());
        if (ogr_driver && ogr_driver != nullptr)
        {
            dataset_ = ogr_driver->Open((dataset_name_).c_str(), false);
        }
#endif
    }
    else
    {
        // open ogr driver
#if GDAL_VERSION_MAJOR >= 2
        dataset_ = reinterpret_cast<gdal_dataset_type>(OGROpen(dataset_name_.c_str(), false, nullptr));
#else
        dataset_ = OGRSFDriverRegistrar::Open(dataset_name_.c_str(), false);
#endif
    }

    if (! dataset_)
    {
        const 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<mapnik::value_integer> layer_by_index = params.get<mapnik::value_integer>("layer_by_index");
    boost::optional<std::string> layer_by_sql = params.get<std::string>("layer_by_sql");

    int passed_parameters = 0;
    passed_parameters += layer_by_name ? 1 : 0;
    passed_parameters += layer_by_index ? 1 : 0;
    passed_parameters += layer_by_sql ? 1 : 0;

    if (passed_parameters > 1)
    {
        throw datasource_exception("OGR Plugin: you can only select an ogr layer by name "
                                   "('layer' parameter), by number ('layer_by_index' parameter), "
                                   "or by sql ('layer_by_sql' parameter), "
                                   "do not supply 2 or more of them at the same time" );
    }

    if (layer_by_name)
    {
        layer_name_ = *layer_by_name;
        layer_.layer_by_name(dataset_, layer_name_);
    }
    else if (layer_by_index)
    {
        int num_layers = dataset_->GetLayerCount();
        if (*layer_by_index >= num_layers)
        {
            std::ostringstream s;
            s << "OGR Plugin: only " << num_layers << " layer(s) exist, cannot find layer by index '" << *layer_by_index << "'";
//.........这里部分代码省略.........

ogr_datasource::ogr_datasource(parameters const& params)
   : datasource(params),
     extent_(),
     type_(datasource::Vector),
     desc_(*params.get<std::string>("type"), *params.get<std::string>("encoding","utf-8")),
     indexed_(false)
{
   OGRRegisterAll();

   boost::optional<std::string> file = params.get<std::string>("file");
   if (!file) throw datasource_exception("missing <file> parameter");

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

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

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

   // initialize layer
   boost::optional<std::string> layer = params.get<std::string>("layer");
   if (!layer) 
   {
      std::string s ("missing <layer> parameter, available layers are: ");
      unsigned num_layers = dataset_->GetLayerCount();
      for (unsigned i = 0; i < num_layers; ++i )
      {
         OGRLayer  *ogr_layer = dataset_->GetLayer(i);
         OGRFeatureDefn* def = ogr_layer->GetLayerDefn();
         if (def != 0) { 
            s += " '";
            s += def->GetName();
            s += "' ";
         } else {
            s += "No layers found!";
         }
      }
      throw datasource_exception(s);
   }
   
   layerName_ = *layer;  
   layer_ = dataset_->GetLayerByName (layerName_.c_str());
   if (! layer_) throw datasource_exception("cannot find <layer> in dataset");
   
   // initialize envelope
   OGREnvelope envelope;
   layer_->GetExtent (&envelope);
   extent_.init (envelope.MinX, envelope.MinY, envelope.MaxX, envelope.MaxY);

   // scan for index file
   size_t breakpoint = dataset_name_.find_last_of (".");
   if (breakpoint == std::string::npos) breakpoint = dataset_name_.length();
   index_name_ = dataset_name_.substr(0, breakpoint) + ".index";
   std::ifstream index_file (index_name_.c_str(), std::ios::in | std::ios::binary);
   if (index_file)
   {
      indexed_=true;
      index_file.close();
   }

   // 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;
//.........这里部分代码省略.........

void sqlite_datasource::bind() const
{
    if (is_bound_) return;
    
    if (!boost::filesystem::exists(dataset_name_))
        throw datasource_exception("Sqlite Plugin: " + dataset_name_ + " does not exist");
          
    dataset_ = new sqlite_connection (dataset_name_);

    std::string table_name = mapnik::table_from_sql(table_);
    
    if (metadata_ != "" && ! extent_initialized_)
    {
        std::ostringstream s;
        s << "SELECT xmin, ymin, xmax, ymax FROM " << metadata_;
        s << " WHERE LOWER(f_table_name) = LOWER('" << table_name << "')";
        boost::scoped_ptr<sqlite_resultset> rs (dataset_->execute_query (s.str()));
        if (rs->is_valid () && rs->step_next())
        {
            double xmin = rs->column_double (0);
            double ymin = rs->column_double (1);
            double xmax = rs->column_double (2);
            double ymax = rs->column_double (3);

            extent_.init (xmin,ymin,xmax,ymax);
            extent_initialized_ = true;
        }
    }

    if (use_spatial_index_)
    {
        std::ostringstream s;
        s << "SELECT COUNT (*) FROM sqlite_master";
        s << " WHERE LOWER(name) = LOWER('idx_" << table_name << "_" << geometry_field_ << "')";
        boost::scoped_ptr<sqlite_resultset> rs (dataset_->execute_query (s.str()));
        if (rs->is_valid () && rs->step_next())
        {
            use_spatial_index_ = rs->column_integer (0) == 1;
        }

#ifdef MAPNIK_DEBUG
        if (! use_spatial_index_)
           std::clog << "Sqlite Plugin: cannot use the spatial index " << std::endl;
#endif
    }
    
    {
        /*
            XXX - This is problematic, if we do not have at least a row,
                  we cannot determine the right columns types and names 
                  as all column_type are SQLITE_NULL
        */

        std::ostringstream s;
        s << "SELECT " << fields_ << " FROM (" << table_name << ") LIMIT 1";

        boost::scoped_ptr<sqlite_resultset> rs (dataset_->execute_query (s.str()));
        if (rs->is_valid () && rs->step_next())
        {
            for (int i = 0; i < rs->column_count (); ++i)
            {
               const int type_oid = rs->column_type (i);
               const char* fld_name = rs->column_name (i);
               switch (type_oid)
               {
                  case SQLITE_INTEGER:
                     desc_.add_descriptor(attribute_descriptor(fld_name,mapnik::Integer));
                     break;
                     
                  case SQLITE_FLOAT:
                     desc_.add_descriptor(attribute_descriptor(fld_name,mapnik::Double));
                     break;
                     
                  case SQLITE_TEXT:
                     desc_.add_descriptor(attribute_descriptor(fld_name,mapnik::String));
                     break;
                     
                  case SQLITE_NULL:
                  case SQLITE_BLOB:
                     break;
                     
                  default:
#ifdef MAPNIK_DEBUG
                     std::clog << "Sqlite Plugin: unknown type_oid=" << type_oid << std::endl;
#endif
                     break;
                }
            }    
        }
    }
    
    is_bound_ = true;
}

void rasterlite_datasource::bind() const
{
    if (is_bound_) return;   
    
    if (!boost::filesystem::exists(dataset_name_)) throw datasource_exception(dataset_name_ + " does not exist");

    void *dataset = open_dataset();
   
    double x0, y0, x1, y1;
    if (rasterliteGetExtent (dataset, &x0, &y0, &x1, &y1) != RASTERLITE_OK)
    {
        std::string error (rasterliteGetLastError(dataset));

	    rasterliteClose (dataset);
   
        throw datasource_exception(error);
    }

    extent_.init(x0,y0,x1,y1);
   
#ifdef MAPNIK_DEBUG
    int srid, auth_srid;
    const char *auth_name;
    const char *ref_sys_name;
    const char *proj4text;

    int tile_count;
    double pixel_x_size, pixel_y_size;
    int levels = rasterliteGetLevels (dataset);

    if (rasterliteGetSrid(dataset, &srid, &auth_name, &auth_srid, &ref_sys_name, &proj4text) != RASTERLITE_OK)
    { 
        std::string error (rasterliteGetLastError(dataset));

	    rasterliteClose (dataset);
   
        throw datasource_exception(error);
    }

    std::clog << "Rasterlite Plugin: Data Source=" << rasterliteGetTablePrefix(dataset) << std::endl;
    std::clog << "Rasterlite Plugin: SRID=" << srid << std::endl;
    std::clog << "Rasterlite Plugin: Authority=" << auth_name << std::endl;
    std::clog << "Rasterlite Plugin: AuthSRID=" << auth_srid << std::endl;
    std::clog << "Rasterlite Plugin: RefSys Name=" << ref_sys_name << std::endl;
    std::clog << "Rasterlite Plugin: Proj4Text=" << proj4text << std::endl;
    std::clog << "Rasterlite Plugin: Extent(" << x0 << "," << y0 << " " << x1 << "," << y1 << ")" << std::endl;
    std::clog << "Rasterlite Plugin: Levels=" << levels << std::endl;
   
    for (int i = 0; i < levels; i++)
    {
        if (rasterliteGetResolution(dataset, i, &pixel_x_size, &pixel_y_size, &tile_count) == RASTERLITE_OK)
        {
            std::clog << "Rasterlite Plugin: Level=" << i
                << " x=" << pixel_x_size << " y=" << pixel_y_size << " tiles=" << tile_count << std::endl;
        }
    }
#endif

    rasterliteClose(dataset);
   
    is_bound_ = true;
}

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

    double lox = 0.0, loy = 0.0, hix = 0.0, hiy = 0.0;

    boost::optional<mapnik::boolean> estimate_extent =
        params_.get<mapnik::boolean>("estimate_extent",false);

    if (estimate_extent && *estimate_extent)
    {
#ifdef MAPNIK_STATS
        mapnik::progress_timer __stats__(std::clog, "occi_datasource::envelope(estimate_extent)");
#endif

        std::ostringstream s;
        s << "SELECT MIN(c.x), MIN(c.y), MAX(c.x), MAX(c.y) FROM ";
        s << " (SELECT SDO_AGGR_MBR(" << geometry_field_ << ") shape FROM " << table_ << ") a, ";
        s << " TABLE(SDO_UTIL.GETVERTICES(a.shape)) c";

        MAPNIK_LOG_DEBUG(occi) << "occi_datasource: " << s.str();

        try
        {
            occi_connection_ptr conn;
            if (use_connection_pool_) conn.set_pool(pool_);
            else                      conn.set_connection(conn_, false);

            ResultSet* rs = conn.execute_query(s.str());
            if (rs && rs->next())
            {
                try
                {
                    lox = lexical_cast<double>(rs->getDouble(1));
                    loy = lexical_cast<double>(rs->getDouble(2));
                    hix = lexical_cast<double>(rs->getDouble(3));
                    hiy = lexical_cast<double>(rs->getDouble(4));
                    extent_.init(lox, loy, hix, hiy);
                    extent_initialized_ = true;
                }
                catch (bad_lexical_cast& ex)
                {
                    MAPNIK_LOG_WARN(occi) << "OCCI Plugin: " << ex.what();
                }
            }
        }
        catch (SQLException& ex)
        {
            throw datasource_exception("OCCI Plugin: " + ex.getMessage());
        }
    }
    else if (use_spatial_index_)
    {
#ifdef MAPNIK_STATS
        mapnik::progress_timer __stats__(std::clog, "occi_datasource::envelope(use_spatial_index)");
#endif

        std::ostringstream s;
        s << "SELECT dim.sdo_lb, dim.sdo_ub FROM ";
        s << METADATA_TABLE << " m, TABLE(m.diminfo) dim ";
        s << " WHERE LOWER(m.table_name) = LOWER('" << table_name_ << "') AND dim.sdo_dimname = 'X'";
        s << " UNION ";
        s << "SELECT dim.sdo_lb, dim.sdo_ub FROM ";
        s << METADATA_TABLE << " m, TABLE(m.diminfo) dim ";
        s << " WHERE LOWER(m.table_name) = LOWER('" << table_name_ << "') AND dim.sdo_dimname = 'Y'";

        MAPNIK_LOG_DEBUG(occi) << "occi_datasource: " << s.str();

        try
        {
            occi_connection_ptr conn;
            if (use_connection_pool_) conn.set_pool(pool_);
            else                      conn.set_connection(conn_, false);

            ResultSet* rs = conn.execute_query(s.str());
            if (rs)
            {
                if (rs->next())
                {
                    try
                    {
                        lox = lexical_cast<double>(rs->getDouble(1));
                        hix = lexical_cast<double>(rs->getDouble(2));
                    }
                    catch (bad_lexical_cast& ex)
                    {
                        MAPNIK_LOG_WARN(occi) << "OCCI Plugin: " << ex.what();
                    }
                }

                if (rs->next())
                {
                    try
                    {
                        loy = lexical_cast<double>(rs->getDouble(1));
                        hiy = lexical_cast<double>(rs->getDouble(2));
                    }
                    catch (bad_lexical_cast& ex)
                    {
//.........这里部分代码省略.........

rasterlite_datasource::rasterlite_datasource(parameters const& params)
    : datasource(params),
      desc_(rasterlite_datasource::name(),"utf-8")
{
    MAPNIK_LOG_DEBUG(rasterlite) << "rasterlite_datasource: Initializing...";

    boost::optional<std::string> file = params.get<std::string>("file");
    if (!file) throw datasource_exception("missing <file> parameter");

    boost::optional<std::string> table = params.get<std::string>("table");
    if (!table) throw datasource_exception("missing <table> parameter");

    table_name_ = *table;

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

    if (!mapnik::util::exists(dataset_name_)) throw datasource_exception(dataset_name_ + " does not exist");

    void *dataset = open_dataset();

    double x0, y0, x1, y1;
    if (rasterliteGetExtent (dataset, &x0, &y0, &x1, &y1) != RASTERLITE_OK)
    {
        std::string error (rasterliteGetLastError(dataset));

        rasterliteClose (dataset);

        throw datasource_exception(error);
    }

    extent_.init(x0,y0,x1,y1);

#ifdef MAPNIK_LOG
    int srid, auth_srid;
    const char *auth_name;
    const char *ref_sys_name;
    const char *proj4text;

    int tile_count;
    double pixel_x_size, pixel_y_size;
    int levels = rasterliteGetLevels (dataset);

    if (rasterliteGetSrid(dataset, &srid, &auth_name, &auth_srid, &ref_sys_name, &proj4text) != RASTERLITE_OK)
    {
        std::string error (rasterliteGetLastError(dataset));

        rasterliteClose (dataset);

        throw datasource_exception(error);
    }

    MAPNIK_LOG_DEBUG(rasterlite) << "rasterlite_datasource: Data Source=" << rasterliteGetTablePrefix(dataset);
    MAPNIK_LOG_DEBUG(rasterlite) << "rasterlite_datasource: SRID=" << srid;
    MAPNIK_LOG_DEBUG(rasterlite) << "rasterlite_datasource: Authority=" << auth_name;
    MAPNIK_LOG_DEBUG(rasterlite) << "rasterlite_datasource: AuthSRID=" << auth_srid;
    MAPNIK_LOG_DEBUG(rasterlite) << "rasterlite_datasource: RefSys Name=" << ref_sys_name;
    MAPNIK_LOG_DEBUG(rasterlite) << "rasterlite_datasource: Proj4Text=" << proj4text;
    MAPNIK_LOG_DEBUG(rasterlite) << "rasterlite_datasource: Extent=" << x0 << "," << y0 << " " << x1 << "," << y1 << ")";
    MAPNIK_LOG_DEBUG(rasterlite) << "rasterlite_datasource: Levels=" << levels;

    for (int i = 0; i < levels; i++)
    {
        if (rasterliteGetResolution(dataset, i, &pixel_x_size, &pixel_y_size, &tile_count) == RASTERLITE_OK)
        {
            MAPNIK_LOG_DEBUG(rasterlite) << "rasterlite_datasource: Level=" << i
                                         << " x=" << pixel_x_size
                                         << " y=" << pixel_y_size
                                         << " tiles=" << tile_count;
        }
    }
#endif

    rasterliteClose(dataset);
}