Avoid copy of vectors in MakeRoute function (#6939)

Author: SiarheiFedartsou

CHANGELOG.md

@@ -24,6 +24,7 @@
     - NodeJS:
       - CHANGED: Use node-api instead of NAN. [#6452](https://github.com/Project-OSRM/osrm-backend/pull/6452)
     - Misc:
+      - CHANGED: Avoid copy of vectors in MakeRoute function. [#6939](https://github.com/Project-OSRM/osrm-backend/pull/6939)
       - FIXED: Fix bugprone-unused-return-value clang-tidy warning. [#6934](https://github.com/Project-OSRM/osrm-backend/pull/6934)
       - FIXED: Fix performance-noexcept-move-constructor clang-tidy warning. [#6931](https://github.com/Project-OSRM/osrm-backend/pull/6933)
       - FIXED: Fix performance-noexcept-swap clang-tidy warning. [#6931](https://github.com/Project-OSRM/osrm-backend/pull/6931)

include/engine/api/route_api.hpp

@@ -340,8 +340,8 @@ class RouteAPI : public BaseAPI
                                   unpacked_path_segments,
                                   source_traversed_in_reverse,
                                   target_traversed_in_reverse);
-        std::vector<guidance::RouteLeg> legs = legs_info.first;
-        std::vector<guidance::LegGeometry> leg_geometries = legs_info.second;
+        std::vector<guidance::RouteLeg> &legs = legs_info.first;
+        std::vector<guidance::LegGeometry> &leg_geometries = legs_info.second;
         auto route = guidance::assembleRoute(legs);
 
         // Fill legs
@@ -716,8 +716,8 @@ class RouteAPI : public BaseAPI
                                   unpacked_path_segments,
                                   source_traversed_in_reverse,
                                   target_traversed_in_reverse);
-        std::vector<guidance::RouteLeg> legs = legs_info.first;
-        std::vector<guidance::LegGeometry> leg_geometries = legs_info.second;
+        std::vector<guidance::RouteLeg> &legs = legs_info.first;
+        std::vector<guidance::LegGeometry> &leg_geometries = legs_info.second;
 
         auto route = guidance::assembleRoute(legs);
         boost::optional<util::json::Value> json_overview =