1 files changed, 86 insertions, 0 deletions
diff --git a/src/mbgl/renderer/sources/render_geojson_source.cpp b/src/mbgl/renderer/sources/render_geojson_source.cpp
index 0099ebcf5e..a688026788 100644
--- a/src/mbgl/renderer/sources/render_geojson_source.cpp
+++ b/src/mbgl/renderer/sources/render_geojson_source.cpp
@@ -7,15 +7,74 @@
 #include <mbgl/algorithm/generate_clip_ids.hpp>
 #include <mbgl/algorithm/generate_clip_ids_impl.hpp>
 
+#include <mapbox/eternal.hpp>
+
 namespace mbgl {
 
 using namespace style;
 
+namespace {
+
+template<typename T, typename C>
+optional<T> getProperty(const C& cont, const typename C::key_type& name) {
+    const auto it = cont.find(name);
+    if (it == cont.end() || !(it->second.template is<T>())) {
+        return nullopt;
+    }
+    return it->second.template get<T>();
+}
+
+using FeatureExtensionGetterPtr = FeatureExtensionValue (*)(std::shared_ptr<style::GeoJSONData>,
+                                                            std::uint32_t,
+                                                            const optional<std::map<std::string, Value>>&);
+
+FeatureExtensionValue getChildren(std::shared_ptr<style::GeoJSONData> clusterData,
+                                  std::uint32_t clusterID,
+                                  const optional<std::map<std::string, Value>>&) {
+    return clusterData->getChildren(clusterID);
+}
+
+FeatureExtensionValue getLeaves(std::shared_ptr<style::GeoJSONData> clusterData,
+                                std::uint32_t clusterID,
+                                const optional<std::map<std::string, Value>>& args) {
+    if (args) {
+        const auto limit = getProperty<uint64_t>(*args, "limit");
+        const auto offset = getProperty<uint64_t>(*args, "offset");
+        // Offset cannot be set without limit.
+        if (limit) {
+            if (offset) {
+                return clusterData->getLeaves(clusterID,
+                                              static_cast<std::uint32_t>(*limit),
+                                              static_cast<std::uint32_t>(*offset));
+            }
+            return clusterData->getLeaves(clusterID, static_cast<std::uint32_t>(*limit));
+        }
+    }
+
+    return clusterData->getLeaves(clusterID);
+}
+
+FeatureExtensionValue getClusterExpansionZoom(std::shared_ptr<style::GeoJSONData> clusterData,
+                                              std::uint32_t clusterID,
+                                              const optional<std::map<std::string, Value>>&) {
+    return Value{static_cast<uint64_t>(clusterData->getClusterExpansionZoom(clusterID))};
+}
+
+MAPBOX_ETERNAL_CONSTEXPR const auto extensionGetters = mapbox::eternal::hash_map<mapbox::eternal::string, FeatureExtensionGetterPtr>({
+    {"children", &getChildren},
+    {"leaves", &getLeaves},
+    {"expansion-zoom", &getClusterExpansionZoom}
+});
+
+}
+
 RenderGeoJSONSource::RenderGeoJSONSource(Immutable<style::GeoJSONSource::Impl> impl_)
     : RenderSource(impl_) {
     tilePyramid.setObserver(this);
 }
 
+RenderGeoJSONSource::~RenderGeoJSONSource() = default;
+
 const style::GeoJSONSource::Impl& RenderGeoJSONSource::impl() const {
     return static_cast<const style::GeoJSONSource::Impl&>(*baseImpl);
 }
@@ -94,6 +153,33 @@ std::vector<Feature> RenderGeoJSONSource::querySourceFeatures(const SourceQueryO
     return tilePyramid.querySourceFeatures(options);
 }
 
+mapbox::util::variant<Value, FeatureCollection>
+RenderGeoJSONSource::queryFeatureExtensions(const Feature& feature,
+                                            const std::string& extension,
+                                            const std::string& extensionField,
+                                            const optional<std::map<std::string, Value>>& args) const {
+    if (extension != "supercluster") {
+        return {};
+    }
+
+    const auto extensionIt = extensionGetters.find(extensionField.c_str());
+    if (extensionIt == extensionGetters.end()) {
+        return {};
+    }
+
+    const auto clusterID = getProperty<uint64_t>(feature.properties, "cluster_id");
+    if (!clusterID) {
+        return {};
+    }
+
+    auto jsonData = data.lock();
+    if (!jsonData) {
+        return {};
+    }
+
+    return extensionIt->second(std::move(jsonData), static_cast<std::uint32_t>(*clusterID), args);
+}
+
 void RenderGeoJSONSource::reduceMemoryUse() {
     tilePyramid.reduceMemoryUse();
 }