mapnik/plugins/input/geojson/geojson_datasource.cpp

/*****************************************************************************
 *
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2015 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
 *
 *****************************************************************************/

#include "geojson_datasource.hpp"
#include "geojson_featureset.hpp"
#include "geojson_index_featureset.hpp"
#include "geojson_memory_index_featureset.hpp"
#include <fstream>
#include <algorithm>

#pragma GCC diagnostic push
#include <mapnik/warning_ignore.hpp>
#include <boost/algorithm/string.hpp>
#include <boost/spirit/include/qi.hpp>
#pragma GCC diagnostic pop

// mapnik
#include <mapnik/boolean.hpp>
#include <mapnik/unicode.hpp>
#include <mapnik/util/utf_conv_win.hpp>
#include <mapnik/feature.hpp>
#include <mapnik/feature_factory.hpp>
#include <mapnik/feature_kv_iterator.hpp>
#include <mapnik/value_types.hpp>
#include <mapnik/box2d.hpp>
#include <mapnik/debug.hpp>
#include <mapnik/proj_transform.hpp>
#include <mapnik/projection.hpp>
#include <mapnik/util/variant.hpp>
#include <mapnik/util/file_io.hpp>
#include <mapnik/util/geometry_to_ds_type.hpp>
#include <mapnik/make_unique.hpp>
#include <mapnik/geometry_adapters.hpp>
#include <mapnik/json/feature_collection_grammar.hpp>
#include <mapnik/json/extract_bounding_box_grammar_impl.hpp>
#include <mapnik/util/fs.hpp>
#include <mapnik/util/spatial_index.hpp>
#include <mapnik/geom_util.hpp>

#if defined(MAPNIK_MEMORY_MAPPED_FILE)
#pragma GCC diagnostic push
#include <mapnik/warning_ignore.hpp>
#include <boost/interprocess/mapped_region.hpp>
#pragma GCC diagnostic pop
#include <mapnik/mapped_memory_cache.hpp>
#endif

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

DATASOURCE_PLUGIN(geojson_datasource)

struct attr_value_converter
{
    mapnik::eAttributeType operator() (mapnik::value_integer) const
    {
        return mapnik::Integer;
    }

    mapnik::eAttributeType operator() (double) const
    {
        return mapnik::Double;
    }

    mapnik::eAttributeType operator() (float) const
    {
        return mapnik::Double;
    }

    mapnik::eAttributeType operator() (bool) const
    {
        return mapnik::Boolean;
    }

    mapnik::eAttributeType operator() (std::string const& ) const
    {
        return mapnik::String;
    }

    mapnik::eAttributeType operator() (mapnik::value_unicode_string const&) const
    {
        return mapnik::String;
    }

    mapnik::eAttributeType operator() (mapnik::value_null const& ) const
    {
        return mapnik::String;
    }
};

geojson_datasource::geojson_datasource(parameters const& params)
  : datasource(params),
    type_(datasource::Vector),
    desc_(geojson_datasource::name(),
          *params.get<std::string>("encoding","utf-8")),
    filename_(),
    inline_string_(),
    extent_(),
    features_(),
    tree_(nullptr)
{
    boost::optional<std::string> inline_string = params.get<std::string>("inline");
    if (inline_string)
    {
        inline_string_ = *inline_string;
    }
    else
    {
        boost::optional<std::string> file = params.get<std::string>("file");
        if (!file) throw mapnik::datasource_exception("GeoJSON Plugin: missing <file> parameter");

        boost::optional<std::string> base = params.get<std::string>("base");
        if (base)
            filename_ = *base + "/" + *file;
        else
            filename_ = *file;
        has_disk_index_ = mapnik::util::exists(filename_ + ".index");
    }

    if (!inline_string_.empty())
    {
        char const* start = inline_string_.c_str();
        char const* end = start + inline_string_.size();
        parse_geojson(start, end);
    }
    else if (has_disk_index_)
    {
        initialise_disk_index(filename_);
    }
    else
    {
        cache_features_ = *params.get<mapnik::boolean_type>("cache_features", true);
#if !defined(MAPNIK_MEMORY_MAPPED_FILE)
        mapnik::util::file file(filename_);
        if (!file)
        {
            throw mapnik::datasource_exception("GeoJSON Plugin: could not open: '" + filename_ + "'");
        }

        std::string file_buffer;
        file_buffer.resize(file.size());
        std::fread(&file_buffer[0], file.size(), 1, file.get());
        char const* start = file_buffer.c_str();
        char const* end = start + file_buffer.length();
        if (cache_features_)
        {
            parse_geojson(start, end);
        }
        else
        {
            initialise_index(start, end);
        }
#else
        boost::optional<mapnik::mapped_region_ptr> mapped_region =
            mapnik::mapped_memory_cache::instance().find(filename_, false);
        if (!mapped_region)
        {
            throw std::runtime_error("could not get file mapping for "+ filename_);
        }

        char const* start = reinterpret_cast<char const*>((*mapped_region)->get_address());
        char const* end = start + (*mapped_region)->get_size();
        if (cache_features_)
        {
            parse_geojson(start, end);
        }
        else
        {
            initialise_index(start, end);
        }
#endif
    }
}

namespace {
using box_type = box2d<double>;
using boxes_type = std::vector<std::pair<box_type, std::pair<std::size_t, std::size_t>>>;
using base_iterator_type = char const*;
const mapnik::transcoder geojson_datasource_static_tr("utf8");
const mapnik::json::feature_collection_grammar<base_iterator_type,mapnik::feature_impl> geojson_datasource_static_fc_grammar(geojson_datasource_static_tr);
const mapnik::json::feature_grammar_callback<base_iterator_type,mapnik::feature_impl> geojson_datasource_static_feature_callback_grammar(geojson_datasource_static_tr);
const mapnik::json::feature_grammar<base_iterator_type, mapnik::feature_impl> geojson_datasource_static_feature_grammar(geojson_datasource_static_tr);
const mapnik::json::extract_bounding_box_grammar<base_iterator_type, boxes_type> geojson_datasource_static_bbox_grammar;
}

void geojson_datasource::initialise_descriptor(mapnik::feature_ptr const& feature)
{
    for ( auto const& kv : *feature)
    {
        auto const& name = std::get<0>(kv);
        if (!desc_.has_name(name))
        {
            desc_.add_descriptor(mapnik::attribute_descriptor(name,
                                                              mapnik::util::apply_visitor(attr_value_converter(),
                                                                                          std::get<1>(kv))));
        }
    }
}

void geojson_datasource::initialise_disk_index(std::string const& filename)
{
    // read extent
    using value_type = std::pair<std::size_t, std::size_t>;
    std::ifstream index(filename_ + ".index", std::ios::binary);
    if (!index) throw mapnik::datasource_exception("GeoJSON Plugin: could not open: '" + filename_ + ".index'");
    extent_ = mapnik::util::spatial_index<value_type,
                                          mapnik::filter_in_box,
                                          std::ifstream>::bounding_box(index);
    mapnik::filter_in_box filter(extent_);
    std::vector<value_type> positions;
    mapnik::util::spatial_index<value_type,
                                mapnik::filter_in_box,
                                std::ifstream>::query_first_n(filter, index, positions, num_features_to_query_);

    mapnik::util::file file(filename_);
    if (!file) throw mapnik::datasource_exception("GeoJSON Plugin: could not open: '" + filename_ + "'");

    for (auto const& pos : positions)
    {
        std::fseek(file.get(), pos.first, SEEK_SET);
        std::vector<char> record;
        record.resize(pos.second);
        std::fread(record.data(), pos.second, 1, file.get());
        auto const* start = record.data();
        auto const*  end = start + record.size();
        mapnik::context_ptr ctx = std::make_shared<mapnik::context_type>();
        mapnik::feature_ptr feature(mapnik::feature_factory::create(ctx,1));
        using namespace boost::spirit;
        standard::space_type space;
        if (!boost::spirit::qi::phrase_parse(start, end,
                                             (geojson_datasource_static_feature_grammar)(boost::phoenix::ref(*feature)), space)
            || start != end)
        {
            throw std::runtime_error("Failed to parse geojson feature");
        }
        initialise_descriptor(feature);
    }
}

template <typename Iterator>
void geojson_datasource::initialise_index(Iterator start, Iterator end)
{
    boxes_type boxes;
    boost::spirit::standard::space_type space;
    Iterator itr = start;
    if (!boost::spirit::qi::phrase_parse(itr, end, (geojson_datasource_static_bbox_grammar)(boost::phoenix::ref(boxes)) , space))
    {
        cache_features_ = true; // force caching single feature
        itr = start; // reset iteraror
        // try parsing as single Feature or single Geometry JSON
        mapnik::context_ptr ctx = std::make_shared<mapnik::context_type>();
        std::size_t start_id = 1;
        mapnik::json::default_feature_callback callback(features_);
        bool result = boost::spirit::qi::phrase_parse(itr, end, (geojson_datasource_static_feature_callback_grammar)
                                                 (boost::phoenix::ref(ctx), boost::phoenix::ref(start_id), boost::phoenix::ref(callback)),
                                                 space);
        if (!result || itr != end)
        {
            if (!inline_string_.empty()) throw mapnik::datasource_exception("geojson_datasource: Failed to parse GeoJSON file from in-memory string");
            else throw mapnik::datasource_exception("geojson_datasource: Failed to parse GeoJSON file '" + filename_ + "'");
        }

        using values_container = std::vector< std::pair<box_type, std::pair<std::size_t, std::size_t>>>;
        values_container values;
        values.reserve(features_.size());

        std::size_t geometry_index = 0;
        for (mapnik::feature_ptr const& f : features_)
        {
            mapnik::box2d<double> box = f->envelope();
            if (box.valid())
            {
                if (geometry_index == 0)
                {
                    extent_ = box;
                }
                else
                {
                    extent_.expand_to_include(box);
                }
                values.emplace_back(box, std::make_pair(geometry_index,0));

            }
            if (geometry_index++ < num_features_to_query_)
            {
                initialise_descriptor(f);
            }
        }
        // packing algorithm
        tree_ = std::make_unique<spatial_index_type>(values);
    }
    else
    {
        // bulk insert initialise r-tree
        tree_ = std::make_unique<spatial_index_type>(boxes);
        // calculate total extent
        std::size_t feature_count = 0;
        for (auto const& item : boxes)
        {
            auto const& box = std::get<0>(item);
            auto const& geometry_index = std::get<1>(item);
            if (!extent_.valid()) extent_ = box;
            else extent_.expand_to_include(box);
            if (feature_count++ < num_features_to_query_)
            {
                // parse first N features to extract attributes schema.
                // NOTE: this doesn't yield correct answer for geoJSON in general, just an indication
                Iterator itr2 = start + geometry_index.first;
                Iterator end2 = itr2 + geometry_index.second;
                mapnik::context_ptr ctx = std::make_shared<mapnik::context_type>();
                mapnik::feature_ptr feature(mapnik::feature_factory::create(ctx,-1)); // temp feature
                if (!boost::spirit::qi::phrase_parse(itr2, end2,
                                                     (geojson_datasource_static_feature_grammar)(boost::phoenix::ref(*feature)), space)
                    || itr2 != end2)
                {
                    throw std::runtime_error("Failed to parse geojson feature");
                }

                initialise_descriptor(feature);
            }
        }
    }
}

template <typename Iterator>
void geojson_datasource::parse_geojson(Iterator start, Iterator end)
{
    using boost::spirit::qi::expectation_failure;
    boost::spirit::standard::space_type space;
    mapnik::context_ptr ctx = std::make_shared<mapnik::context_type>();
    std::size_t start_id = 1;

    mapnik::json::default_feature_callback callback(features_);
    Iterator itr = start;

    try
    {
        bool result = boost::spirit::qi::phrase_parse(itr, end, (geojson_datasource_static_fc_grammar)
                                                      (boost::phoenix::ref(ctx),boost::phoenix::ref(start_id), boost::phoenix::ref(callback)),
                                                      space);
        if (!result || itr != end)
        {
            itr = start;
            // try parsing as single Feature or single Geometry JSON
            result = boost::spirit::qi::phrase_parse(itr, end, (geojson_datasource_static_feature_callback_grammar)
                                                     (boost::phoenix::ref(ctx),boost::phoenix::ref(start_id), boost::phoenix::ref(callback)),
                                                     space);
            if (!result || itr != end)
            {
                if (!inline_string_.empty()) throw mapnik::datasource_exception("geojson_datasource: Failed parse GeoJSON file from in-memory string");
                else throw mapnik::datasource_exception("geojson_datasource: Failed parse GeoJSON file '" + filename_ + "'");
            }
        }
    }
    catch (expectation_failure<char const*> const& ex)
    {
        itr = start;
        // try parsing as single Feature or single Geometry JSON
        bool result = boost::spirit::qi::phrase_parse(itr, end, (geojson_datasource_static_feature_callback_grammar)
                                                      (boost::phoenix::ref(ctx),boost::phoenix::ref(start_id), boost::phoenix::ref(callback)),
                                                      space);
        if (!result || itr != end)
        {
            if (!inline_string_.empty()) throw mapnik::datasource_exception("geojson_datasource: Failed parse GeoJSON file from in-memory string");
            else throw mapnik::datasource_exception("geojson_datasource: Failed parse GeoJSON file '" + filename_ + "'");
        }
    }

    using values_container = std::vector< std::pair<box_type, std::pair<std::size_t, std::size_t>>>;
    values_container values;
    values.reserve(features_.size());

    std::size_t geometry_index = 0;
    for (mapnik::feature_ptr const& f : features_)
    {
        mapnik::box2d<double> box = f->envelope();
        if (box.valid())
        {
            if (geometry_index == 0)
            {
                extent_ = box;

            }
            else
            {
                extent_.expand_to_include(box);
            }
            values.emplace_back(box, std::make_pair(geometry_index,0));
        }
        if (geometry_index < num_features_to_query_)
        {
            initialise_descriptor(f);
        }
        ++geometry_index;
    }
    // packing algorithm
    tree_ = std::make_unique<spatial_index_type>(values);

}

geojson_datasource::~geojson_datasource() {}

const char * geojson_datasource::name()
{
    return "geojson";
}

mapnik::datasource::datasource_t geojson_datasource::type() const
{
    return type_;
}

mapnik::box2d<double> geojson_datasource::envelope() const
{
    return extent_;
}

mapnik::layer_descriptor geojson_datasource::get_descriptor() const
{
    return desc_;
}

boost::optional<mapnik::datasource_geometry_t> geojson_datasource::get_geometry_type() const
{
    boost::optional<mapnik::datasource_geometry_t> result;
    int multi_type = 0;
    if (has_disk_index_)
    {
        using value_type = std::pair<std::size_t, std::size_t>;
        std::ifstream index(filename_ + ".index", std::ios::binary);
        if (!index) throw mapnik::datasource_exception("GeoJSON Plugin: could not open: '" + filename_ + ".index'");
        mapnik::filter_in_box filter(extent_);
        std::vector<value_type> positions;
        mapnik::util::spatial_index<value_type,
                                    mapnik::filter_in_box,
                                    std::ifstream>::query_first_n(filter, index, positions, num_features_to_query_);

        mapnik::util::file file(filename_);

        if (!file) throw mapnik::datasource_exception("GeoJSON Plugin: could not open: '" + filename_ + "'");

        for (auto const& pos : positions)
        {
            std::fseek(file.get(), pos.first, SEEK_SET);
            std::vector<char> record;
            record.resize(pos.second);
            std::fread(record.data(), pos.second, 1, file.get());
            auto const* start = record.data();
            auto const*  end = start + record.size();
            mapnik::context_ptr ctx = std::make_shared<mapnik::context_type>();
            mapnik::feature_ptr feature(mapnik::feature_factory::create(ctx, -1)); // temp feature
            using namespace boost::spirit;
            standard::space_type space;
            if (!boost::spirit::qi::phrase_parse(start, end,
                                                 (geojson_datasource_static_feature_grammar)(boost::phoenix::ref(*feature)), space)
                || start != end)
            {
                throw std::runtime_error("Failed to parse geojson feature");
            }
            result = mapnik::util::to_ds_type(feature->get_geometry());
            if (result)
            {
                int type = static_cast<int>(*result);
                if (multi_type > 0 && multi_type != type)
                {
                    result.reset(mapnik::datasource_geometry_t::Collection);
                    return result;
                }
                multi_type = type;
            }
        }
    }
    else if (cache_features_)
    {
        unsigned num_features = features_.size();
        for (unsigned i = 0; i < num_features && i < num_features_to_query_; ++i)
        {
            result = mapnik::util::to_ds_type(features_[i]->get_geometry());
            if (result)
            {
                int type = static_cast<int>(*result);
                if (multi_type > 0 && multi_type != type)
                {
                    result.reset(mapnik::datasource_geometry_t::Collection);
                    return result;
                }
                multi_type = type;
            }
        }
    }
    else
    {
        mapnik::util::file file(filename_);
        if (!file)
        {
            throw mapnik::datasource_exception("GeoJSON Plugin: could not open: '" + filename_ + "'");
        }
        auto itr = tree_->qbegin(boost::geometry::index::intersects(extent_));
        auto end = tree_->qend();
        mapnik::context_ptr ctx = std::make_shared<mapnik::context_type>();
        for (std::size_t count = 0; itr !=end &&  count < num_features_to_query_; ++itr,++count)
        {
            geojson_datasource::item_type const& item = *itr;
            std::size_t file_offset = item.second.first;
            std::size_t size = item.second.second;

            std::fseek(file.get(), file_offset, SEEK_SET);
            std::vector<char> json;
            json.resize(size);
            std::fread(json.data(), size, 1, file.get());

            using chr_iterator_type = char const*;
            chr_iterator_type start2 = json.data();
            chr_iterator_type end2 = start2 + json.size();

            using namespace boost::spirit;
            standard::space_type space;
            mapnik::feature_ptr feature(mapnik::feature_factory::create(ctx, -1)); // temp feature
            if (!qi::phrase_parse(start2, end2, (geojson_datasource_static_feature_grammar)(boost::phoenix::ref(*feature)), space))
            {
                throw std::runtime_error("Failed to parse geojson feature");
            }
            result = mapnik::util::to_ds_type(feature->get_geometry());
            if (result)
            {
                int type = static_cast<int>(*result);
                if (multi_type > 0 && multi_type != type)
                {
                    result.reset(mapnik::datasource_geometry_t::Collection);
                    return result;
                }
                multi_type = type;
            }
        }
    }
    return result;
}

mapnik::featureset_ptr geojson_datasource::features(mapnik::query const& q) const
{
    // if the query box intersects our world extent then query for features
    mapnik::box2d<double> const& box = q.get_bbox();
    if (extent_.intersects(box))
    {
        geojson_featureset::array_type index_array;
        if (tree_)
        {
            tree_->query(boost::geometry::index::intersects(box),std::back_inserter(index_array));
            // sort index array to preserve original feature ordering in GeoJSON
            std::sort(index_array.begin(),index_array.end(),
                      [] (item_type const& item0, item_type const& item1)
                      {
                          return item0.second.first < item1.second.first;
                      });
            if (cache_features_)
            {
                return std::make_shared<geojson_featureset>(features_, std::move(index_array));
            }
            else
            {
                return std::make_shared<geojson_memory_index_featureset>(filename_, std::move(index_array));
            }
        }
        else if (has_disk_index_)
        {
            mapnik::filter_in_box filter(q.get_bbox());
            return std::make_shared<geojson_index_featureset>(filename_, filter);
        }

    }
    // otherwise return an empty featureset pointer
    return mapnik::featureset_ptr();
}

mapnik::featureset_ptr geojson_datasource::features_at_point(mapnik::coord2d const& pt, double tol) const
{
    mapnik::box2d<double> query_bbox(pt, pt);
    query_bbox.pad(tol);
    mapnik::query q(query_bbox);
    for (auto const& attr_info : desc_.get_descriptors())
    {
        q.add_property_name(attr_info.get_name());
    }
    return features(q);
}