[core] GeometryCollection must not be implicitly copied

3 files changed, 19 insertions, 13 deletions

diff --git a/src/mbgl/tile/geometry_tile_data.cpp b/src/mbgl/tile/geometry_tile_data.cpp
index c7aea35944..db9f37ad4b 100644
--- a/src/mbgl/tile/geometry_tile_data.cpp
+++ b/src/mbgl/tile/geometry_tile_data.cpp
@@ -57,32 +57,31 @@ std::vector<GeometryCollection> classifyRings(const GeometryCollection& rings) {
     std::size_t len = rings.size();
 
     if (len <= 1) {
-        polygons.push_back(rings);
+        polygons.emplace_back(rings.clone());
         return polygons;
     }
 
     GeometryCollection polygon;
     int8_t ccw = 0;
 
-    for (std::size_t i = 0; i < len; i++) {
-        double area = signedArea(rings[i]);
-
-        if (area == 0)
-            continue;
+    for (const auto& ring : rings) {
+        double area = signedArea(ring);
+        if (area == 0) continue;
 
-        if (ccw == 0)
+        if (ccw == 0) {
             ccw = (area < 0 ? -1 : 1);
+        }
 
         if (ccw == (area < 0 ? -1 : 1) && !polygon.empty()) {
-            polygons.push_back(polygon);
-            polygon.clear();
+            polygons.emplace_back(std::move(polygon));
         }
 
-        polygon.push_back(rings[i]);
+        polygon.emplace_back(ring);
     }
 
-    if (!polygon.empty())
-        polygons.push_back(polygon);
+    if (!polygon.empty()) {
+        polygons.emplace_back(std::move(polygon));
+    }
 
     return polygons;
 }
diff --git a/src/mbgl/tile/geometry_tile_data.hpp b/src/mbgl/tile/geometry_tile_data.hpp
index a0d41608a3..203afcace7 100644
--- a/src/mbgl/tile/geometry_tile_data.hpp
+++ b/src/mbgl/tile/geometry_tile_data.hpp
@@ -35,6 +35,13 @@ public:
     GeometryCollection(Args&&... args) : std::vector<GeometryCoordinates>(std::forward<Args>(args)...) {}
     GeometryCollection(std::initializer_list<GeometryCoordinates> args)
       : std::vector<GeometryCoordinates>(std::move(args)) {}
+    GeometryCollection(GeometryCollection&&) = default;
+    GeometryCollection& operator=(GeometryCollection&&) = default;
+
+    GeometryCollection clone() const { return GeometryCollection(*this); }
+
+private:
+    GeometryCollection(const GeometryCollection&) = default;
 };
 
 class GeometryTileFeature {
diff --git a/src/mbgl/tile/geometry_tile_worker.cpp b/src/mbgl/tile/geometry_tile_worker.cpp
index a69825d346..f4d57e5bfc 100644
--- a/src/mbgl/tile/geometry_tile_worker.cpp
+++ b/src/mbgl/tile/geometry_tile_worker.cpp
@@ -382,7 +382,7 @@ void GeometryTileWorker::parse() {
                 if (!filter(expression::EvaluationContext { static_cast<float>(this->id.overscaledZ), feature.get() }))
                     continue;
 
-                GeometryCollection geometries = feature->getGeometries();
+                const GeometryCollection& geometries = feature->getGeometries();
                 bucket->addFeature(*feature, geometries, {}, PatternLayerMap ());
                 featureIndex->insert(geometries, i, sourceLayerID, leaderImpl.id);
             }