[core] create GeoJSON tiles from inline GeoJSON in sources

src/mbgl/map/source.cpp

@@ -4,6 +4,7 @@
 #include <mbgl/map/tile.hpp>
 #include <mbgl/map/vector_tile.hpp>
 #include <mbgl/annotation/annotation_tile.hpp>
+#include <mbgl/tile/geojson_tile.hpp>
 #include <mbgl/renderer/painter.hpp>
 #include <mbgl/util/exception.hpp>
 #include <mbgl/util/constants.hpp>
@@ -207,6 +208,8 @@ TileData::State Source::addTile(const TileID& id, const StyleUpdateParameters& p
                 monitor = std::make_unique<VectorTileMonitor>(info, normalized_id, parameters.pixelRatio);
             } else if (info.type == SourceType::Annotations) {
                 monitor = std::make_unique<AnnotationTileMonitor>(normalized_id, parameters.data);
+            } else if (info.type == SourceType::GeoJSON) {
+                monitor = std::make_unique<GeoJSONTileMonitor>(info.geojsonvt.get(), normalized_id);
             } else {
                 Log::Warning(Event::Style, "Source type '%s' is not implemented", SourceTypeClass(info.type).c_str());
                 return TileData::State::invalid;

src/mbgl/map/source_info.cpp

@@ -3,6 +3,8 @@
 #include <mbgl/util/string.hpp>
 #include <mbgl/util/token.hpp>
 
+#include <mapbox/geojsonvt.hpp>
+
 namespace mbgl {
 
 namespace {
@@ -83,6 +85,9 @@ void parse(const rapidjson::Value& value, std::array<float, N>& target, const ch
 
 } // end namespace
 
+// Destructor in implementation file because header only contains forward declarations.
+SourceInfo::~SourceInfo() = default;
+
 void SourceInfo::parseTileJSONProperties(const rapidjson::Value& value) {
     parse(value, tiles, "tiles");
     parse(value, min_zoom, "minzoom");

src/mbgl/map/source_info.hpp

@@ -14,10 +14,18 @@
 #include <vector>
 #include <cstdint>
 
+namespace mapbox {
+namespace geojsonvt {
+class GeoJSONVT;
+} // namespace geojsonvt
+} // namespace mapbox
+
 namespace mbgl {
 
 class SourceInfo : private util::noncopyable {
 public:
+    ~SourceInfo();
+
     SourceType type = SourceType::Vector;
     std::string url;
     std::vector<std::string> tiles;
@@ -28,6 +36,7 @@ class SourceInfo : private util::noncopyable {
     std::array<float, 3> center = { { 0, 0, 0 } };
     std::array<float, 4> bounds = { { -180, -90, 180, 90 } };
     std::string source_id = "";
+    std::unique_ptr<mapbox::geojsonvt::GeoJSONVT> geojsonvt;
 
     void parseTileJSONProperties(const rapidjson::Value&);
     std::string tileURL(const TileID& id, float pixelRatio) const;

src/mbgl/style/style_parser.cpp

@@ -168,11 +168,10 @@ bool StyleParser::parseGeoJSONSource(Source& source, const JSVal& sourceVal) {
     if (dataVal.IsString()) {
         // We need to load an external GeoJSON file
         source.info.url = { dataVal.GetString(), dataVal.GetStringLength() };
-
     } else if (dataVal.IsObject()) {
         // We need to parse dataVal as a GeoJSON object
-        auto geojsonvt = std::make_unique<mapbox::geojsonvt::GeoJSONVT>(mapbox::geojsonvt::Convert::convert(dataVal, 0));
-        // TODO
+        using namespace mapbox::geojsonvt;
+        source.info.geojsonvt = std::make_unique<GeoJSONVT>(Convert::convert(dataVal, 0));
     } else {
         Log::Warning(Event::ParseStyle, "GeoJSON data must be a URL or an object");
         return false;

src/mbgl/tile/geojson_tile.cpp

@@ -0,0 +1,134 @@
+#include <mbgl/tile/geojson_tile.hpp>
+#include <mbgl/storage/file_source.hpp>
+#include <mapbox/geojsonvt.hpp>
+
+namespace mbgl {
+
+GeoJSONTileFeature::GeoJSONTileFeature(FeatureType type_,
+                                       GeometryCollection&& geometries_,
+                                       GeoJSONTileFeature::Tags&& tags_)
+    : type(type_), geometries(std::move(geometries_)), tags(std::move(tags_)) {
+}
+
+FeatureType GeoJSONTileFeature::getType() const {
+    return type;
+}
+
+mapbox::util::optional<Value> GeoJSONTileFeature::getValue(const std::string& key) const {
+    auto it = tags.find(key);
+    if (it != tags.end()) {
+        return mapbox::util::optional<Value>(it->second);
+    }
+    return mapbox::util::optional<Value>();
+}
+
+GeometryCollection GeoJSONTileFeature::getGeometries() const {
+    return geometries;
+}
+
+GeoJSONTileLayer::GeoJSONTileLayer(Features&& features_) : features(std::move(features_)) {
+}
+
+std::size_t GeoJSONTileLayer::featureCount() const {
+    return features.size();
+}
+
+util::ptr<const GeometryTileFeature> GeoJSONTileLayer::getFeature(std::size_t i) const {
+    return features[i];
+}
+
+GeoJSONTile::GeoJSONTile(std::shared_ptr<GeoJSONTileLayer> layer_) : layer(std::move(layer_)) {
+}
+
+util::ptr<GeometryTileLayer> GeoJSONTile::getLayer(const std::string&) const {
+    // We're ignoring the layer name because GeoJSON tiles only have one layer.
+    return layer;
+}
+
+// Converts the geojsonvt::Tile to a a GeoJSONTile. They have a differing internal structure.
+std::unique_ptr<GeoJSONTile> convertTile(const mapbox::geojsonvt::Tile& tile) {
+    std::shared_ptr<GeoJSONTileLayer> layer;
+
+    if (tile) {
+        std::vector<std::shared_ptr<const GeoJSONTileFeature>> features;
+        std::vector<Coordinate> line;
+
+        for (auto& feature : tile.features) {
+            const FeatureType featureType =
+                (feature.type == mapbox::geojsonvt::TileFeatureType::Point
+                     ? FeatureType::Point
+                     : (feature.type == mapbox::geojsonvt::TileFeatureType::LineString
+                            ? FeatureType::LineString
+                            : (feature.type == mapbox::geojsonvt::TileFeatureType::Polygon
+                                   ? FeatureType::Polygon
+                                   : FeatureType::Unknown)));
+            if (featureType == FeatureType::Unknown) {
+                continue;
+            }
+
+            GeometryCollection geometry;
+
+            // Flatten the geometry; GeoJSONVT distinguishes between a Points array and Rings array
+            // (Points = GeoJSON types Point, MultiPoint, LineString)
+            // (Rings = GeoJSON types MultiLineString, Polygon, MultiPolygon)
+            // However, in Mapbox GL, we use one structure for both types, and just have one outer
+            // element for Points.
+            if (feature.tileGeometry.is<mapbox::geojsonvt::TilePoints>()) {
+                line.clear();
+                for (auto& point : feature.tileGeometry.get<mapbox::geojsonvt::TilePoints>()) {
+                    line.emplace_back(point.x, point.y);
+                }
+                geometry.emplace_back(std::move(line));
+            } else if (feature.tileGeometry.is<mapbox::geojsonvt::TileRings>()) {
+                for (auto& ring : feature.tileGeometry.get<mapbox::geojsonvt::TileRings>()) {
+                    line.clear();
+                    for (auto& point : ring) {
+                        line.emplace_back(point.x, point.y);
+                    }
+                    geometry.emplace_back(std::move(line));
+                }
+            }
+
+            GeoJSONTileFeature::Tags tags{ feature.tags.begin(), feature.tags.end() };
+
+            features.emplace_back(std::make_shared<GeoJSONTileFeature>(
+                featureType, std::move(geometry), std::move(tags)));
+        }
+
+        layer = std::make_unique<GeoJSONTileLayer>(std::move(features));
+    }
+
+    return std::make_unique<GeoJSONTile>(layer);
+}
+
+GeoJSONTileMonitor::GeoJSONTileMonitor(mapbox::geojsonvt::GeoJSONVT* geojsonvt_, const TileID& id)
+    : tileID(id), geojsonvt(geojsonvt_) {
+}
+
+GeoJSONTileMonitor::~GeoJSONTileMonitor() = default;
+
+// A monitor can have its GeoJSONVT object swapped out (e.g. when loading a new GeoJSON file).
+// In that case, we're sending new notifications to all observers.
+void GeoJSONTileMonitor::setGeoJSONVT(mapbox::geojsonvt::GeoJSONVT* vt) {
+    // Don't duplicate notifications in case of nil changes.
+    if (geojsonvt != vt) {
+        geojsonvt = vt;
+        update();
+    }
+}
+
+void GeoJSONTileMonitor::update() {
+    if (geojsonvt) {
+        auto tile = convertTile(geojsonvt->getTile(tileID.z, tileID.x, tileID.y));
+        callback(nullptr, std::move(tile), Seconds::zero(), Seconds::zero());
+    }
+}
+
+std::unique_ptr<FileRequest>
+GeoJSONTileMonitor::monitorTile(const GeometryTileMonitor::Callback& cb) {
+    callback = cb;
+    update();
+    return nullptr;
+}
+
+} // namespace mbgl

src/mbgl/tile/geojson_tile.hpp

@@ -0,0 +1,78 @@
+#ifndef MBGL_ANNOTATION_GEOJSON_VT_TILE
+#define MBGL_ANNOTATION_GEOJSON_VT_TILE
+
+#include <mbgl/map/geometry_tile.hpp>
+#include <mbgl/map/tile_id.hpp>
+
+#include <unordered_map>
+
+namespace mapbox {
+namespace geojsonvt {
+class GeoJSONVT;
+} // namespace geojsonvt
+} // namespace mapbox
+
+namespace mbgl {
+
+// Implements a simple in-memory Tile type that holds GeoJSON values. A GeoJSON tile can only have
+// one layer, and it is always returned regardless of which layer is requested.
+
+class GeoJSONTileFeature : public GeometryTileFeature {
+public:
+    using Tags = std::unordered_map<std::string, std::string>;
+
+    GeoJSONTileFeature(FeatureType, GeometryCollection&&, Tags&& = {});
+    FeatureType getType() const override;
+    mapbox::util::optional<Value> getValue(const std::string&) const override;
+    GeometryCollection getGeometries() const override;
+
+private:
+    const FeatureType type;
+    const GeometryCollection geometries;
+    const Tags tags;
+};
+
+class GeoJSONTileLayer : public GeometryTileLayer {
+public:
+    using Features = std::vector<std::shared_ptr<const GeoJSONTileFeature>>;
+
+    GeoJSONTileLayer(Features&&);
+    std::size_t featureCount() const override;
+    util::ptr<const GeometryTileFeature> getFeature(std::size_t) const override;
+
+private:
+    const Features features;
+};
+
+class GeoJSONTile : public GeometryTile {
+public:
+    GeoJSONTile(std::shared_ptr<GeoJSONTileLayer>);
+    util::ptr<GeometryTileLayer> getLayer(const std::string&) const override;
+
+private:
+    const std::shared_ptr<GeoJSONTileLayer> layer;
+};
+
+class GeoJSONTileMonitor : public GeometryTileMonitor {
+public:
+    GeoJSONTileMonitor(mapbox::geojsonvt::GeoJSONVT*, const TileID&);
+    virtual ~GeoJSONTileMonitor();
+
+    std::unique_ptr<FileRequest> monitorTile(const GeometryTileMonitor::Callback&) override;
+
+    void setGeoJSONVT(mapbox::geojsonvt::GeoJSONVT*);
+
+private:
+    void update();
+
+public:
+    const TileID tileID;
+
+private:
+    mapbox::geojsonvt::GeoJSONVT* geojsonvt = nullptr;
+    GeometryTileMonitor::Callback callback;
+};
+
+} // namespace mbgl
+
+#endif