Use std::variant instead of mapbox::util::variant (#6903)

Author: SiarheiFedartsou

.github/workflows/osrm-backend.yml

@@ -274,15 +274,6 @@ jobs:
             CXXCOMPILER: g++-12
             CXXFLAGS: '-Wno-array-bounds -Wno-uninitialized'
 
-          - name: gcc-11-release
-            continue-on-error: false
-            node: 20
-            runs-on: ubuntu-22.04
-            BUILD_TOOLS: ON
-            BUILD_TYPE: Release
-            CCOMPILER: gcc-11
-            CXXCOMPILER: g++-11
-
           - name: conan-linux-release-node
             build_node_package: true
             continue-on-error: false

CHANGELOG.md

@@ -22,6 +22,7 @@
     - NodeJS:
       - CHANGED: Use node-api instead of NAN. [#6452](https://github.com/Project-OSRM/osrm-backend/pull/6452)
     - Misc:
+      - CHANGED: Use std::variant instead of mapbox::util::variant. [#6903](https://github.com/Project-OSRM/osrm-backend/pull/6903)
       - CHANGED: Bump rapidjson to version f9d53419e912910fd8fa57d5705fa41425428c35 [#6906](https://github.com/Project-OSRM/osrm-backend/pull/6906)
       - CHANGED: Bump mapbox/variant to version 1.2.0 [#6898](https://github.com/Project-OSRM/osrm-backend/pull/6898)
       - CHANGED: Avoid copy of std::function-based callback in path unpacking [#6895](https://github.com/Project-OSRM/osrm-backend/pull/6895)

CMakeLists.txt

@@ -121,7 +121,6 @@ endif()
 include_directories(BEFORE ${CMAKE_CURRENT_BINARY_DIR}/include/)
 include_directories(BEFORE ${CMAKE_CURRENT_SOURCE_DIR}/include/)
 include_directories(SYSTEM ${CMAKE_CURRENT_SOURCE_DIR}/third_party/sol2-3.3.0/include)
-include_directories(SYSTEM ${CMAKE_CURRENT_SOURCE_DIR}/third_party/variant/include)
 
 set(BOOST_COMPONENTS date_time chrono filesystem iostreams program_options regex system thread unit_test_framework)
 
@@ -607,7 +606,6 @@ if (BUILD_ROUTED)
   set_property(TARGET osrm-routed PROPERTY INSTALL_RPATH_USE_LINK_PATH TRUE)
 endif()
 
-file(GLOB VariantGlob third_party/variant/include/mapbox/*.hpp)
 file(GLOB FlatbuffersGlob third_party/flatbuffers/include/flatbuffers/*.h)
 file(GLOB LibraryGlob include/osrm/*.hpp)
 file(GLOB ParametersGlob include/engine/api/*_parameters.hpp)
@@ -627,7 +625,6 @@ install(FILES ${ContractorHeader} DESTINATION include/osrm/contractor)
 install(FILES ${LibraryGlob} DESTINATION include/osrm)
 install(FILES ${ParametersGlob} DESTINATION include/osrm/engine/api)
 install(FILES ${ApiHeader} DESTINATION include/osrm/engine/api)
-install(FILES ${VariantGlob} DESTINATION include/mapbox)
 install(FILES ${FlatbuffersGlob} DESTINATION include/flatbuffers)
 install(TARGETS osrm-extract DESTINATION bin)
 install(TARGETS osrm-partition DESTINATION bin)

example/example.cpp

@@ -57,15 +57,15 @@ int main(int argc, const char *argv[])
     // Execute routing request, this does the heavy lifting
     const auto status = osrm.Route(params, result);
 
-    auto &json_result = result.get<json::Object>();
+    auto &json_result = std::get<json::Object>(result);
     if (status == Status::Ok)
     {
-        auto &routes = json_result.values["routes"].get<json::Array>();
+        auto &routes = std::get<json::Array>(json_result.values["routes"]);
 
         // Let's just use the first route
-        auto &route = routes.values.at(0).get<json::Object>();
-        const auto distance = route.values["distance"].get<json::Number>().value;
-        const auto duration = route.values["duration"].get<json::Number>().value;
+        auto &route = std::get<json::Object>(routes.values.at(0));
+        const auto distance = std::get<json::Number>(route.values["distance"]).value;
+        const auto duration = std::get<json::Number>(route.values["duration"]).value;
 
         // Warn users if extract does not contain the default coordinates from above
         if (distance == 0 || duration == 0)
@@ -80,8 +80,8 @@ int main(int argc, const char *argv[])
     }
     else if (status == Status::Error)
     {
-        const auto code = json_result.values["code"].get<json::String>().value;
-        const auto message = json_result.values["message"].get<json::String>().value;
+        const auto code = std::get<json::String>(json_result.values["code"]).value;
+        const auto message = std::get<json::String>(json_result.values["message"]).value;
 
         std::cout << "Code: " << code << "\n";
         std::cout << "Message: " << code << "\n";

include/engine/api/base_result.hpp

@@ -2,16 +2,15 @@
 #define ENGINE_API_BASE_RESULT_HPP
 
 #include <flatbuffers/flatbuffers.h>
-#include <mapbox/variant.hpp>
+#include <variant>
 
 #include <string>
 
 #include "util/json_container.hpp"
 
 namespace osrm::engine::api
 {
-using ResultT =
-    mapbox::util::variant<util::json::Object, std::string, flatbuffers::FlatBufferBuilder>;
+using ResultT = std::variant<util::json::Object, std::string, flatbuffers::FlatBufferBuilder>;
 } // namespace osrm::engine::api
 
 #endif

include/engine/api/json_factory.hpp

@@ -41,7 +41,7 @@ inline bool hasValidLanes(const guidance::IntermediateIntersection &intersection
     return intersection.lanes.lanes_in_turn > 0;
 }
 
-util::json::Array coordinateToLonLat(const util::Coordinate &coordinate);
+util::json::Value coordinateToLonLat(const util::Coordinate &coordinate);
 
 /**
  * Ensures that a bearing value is a whole number, and clamped to the range 0-359
@@ -79,7 +79,7 @@ util::json::Object makeGeoJSONGeometry(ForwardIter begin, ForwardIter end)
         coordinates.values.push_back(location);
         coordinates.values.push_back(location);
     }
-    geojson.values["coordinates"] = std::move(coordinates);
+    geojson.values["coordinates"] = util::json::Value{std::move(coordinates)};
 
     return geojson;
 }

include/engine/api/match_api.hpp

@@ -30,14 +30,14 @@ class MatchAPI final : public RouteAPI
                       osrm::engine::api::ResultT &response) const
     {
         BOOST_ASSERT(sub_matchings.size() == sub_routes.size());
-        if (response.is<flatbuffers::FlatBufferBuilder>())
+        if (std::holds_alternative<flatbuffers::FlatBufferBuilder>(response))
         {
-            auto &fb_result = response.get<flatbuffers::FlatBufferBuilder>();
+            auto &fb_result = std::get<flatbuffers::FlatBufferBuilder>(response);
             MakeResponse(sub_matchings, sub_routes, fb_result);
         }
         else
         {
-            auto &json_result = response.get<util::json::Object>();
+            auto &json_result = std::get<util::json::Object>(response);
             MakeResponse(sub_matchings, sub_routes, json_result);
         }
     }

include/engine/api/nearest_api.hpp

@@ -29,14 +29,14 @@ class NearestAPI final : public BaseAPI
         BOOST_ASSERT(phantom_nodes.size() == 1);
         BOOST_ASSERT(parameters.coordinates.size() == 1);
 
-        if (response.is<flatbuffers::FlatBufferBuilder>())
+        if (std::holds_alternative<flatbuffers::FlatBufferBuilder>(response))
         {
-            auto &fb_result = response.get<flatbuffers::FlatBufferBuilder>();
+            auto &fb_result = std::get<flatbuffers::FlatBufferBuilder>(response);
             MakeResponse(phantom_nodes, fb_result);
         }
         else
         {
-            auto &json_result = response.get<util::json::Object>();
+            auto &json_result = std::get<util::json::Object>(response);
             MakeResponse(phantom_nodes, json_result);
         }
     }

include/engine/api/route_api.hpp

@@ -50,14 +50,14 @@ class RouteAPI : public BaseAPI
     {
         BOOST_ASSERT(!raw_routes.routes.empty());
 
-        if (response.is<flatbuffers::FlatBufferBuilder>())
+        if (std::holds_alternative<flatbuffers::FlatBufferBuilder>(response))
         {
-            auto &fb_result = response.get<flatbuffers::FlatBufferBuilder>();
+            auto &fb_result = std::get<flatbuffers::FlatBufferBuilder>(response);
             MakeResponse(raw_routes, waypoint_candidates, fb_result);
         }
         else
         {
-            auto &json_result = response.get<util::json::Object>();
+            auto &json_result = std::get<util::json::Object>(response);
             MakeResponse(raw_routes, waypoint_candidates, json_result);
         }
     }
@@ -158,8 +158,8 @@ class RouteAPI : public BaseAPI
     }
 
     template <typename ForwardIter>
-    mapbox::util::variant<flatbuffers::Offset<flatbuffers::String>,
-                          flatbuffers::Offset<flatbuffers::Vector<const fbresult::Position *>>>
+    std::variant<flatbuffers::Offset<flatbuffers::String>,
+                 flatbuffers::Offset<flatbuffers::Vector<const fbresult::Position *>>>
     MakeGeometry(flatbuffers::FlatBufferBuilder &builder, ForwardIter begin, ForwardIter end) const
     {
         if (parameters.geometries == RouteParameters::GeometriesType::Polyline)
@@ -408,8 +408,8 @@ class RouteAPI : public BaseAPI
 
         // Fill geometry
         auto overview = MakeOverview(leg_geometries);
-        mapbox::util::variant<flatbuffers::Offset<flatbuffers::String>,
-                              flatbuffers::Offset<flatbuffers::Vector<const fbresult::Position *>>>
+        std::variant<flatbuffers::Offset<flatbuffers::String>,
+                     flatbuffers::Offset<flatbuffers::Vector<const fbresult::Position *>>>
             geometry;
         if (overview)
         {
@@ -426,8 +426,7 @@ class RouteAPI : public BaseAPI
         routeObject.add_legs(legs_vector);
         if (overview)
         {
-            mapbox::util::apply_visitor(GeometryVisitor<fbresult::RouteObjectBuilder>(routeObject),
-                                        geometry);
+            std::visit(GeometryVisitor<fbresult::RouteObjectBuilder>(routeObject), geometry);
         }
 
         return routeObject.Finish();
@@ -644,7 +643,7 @@ class RouteAPI : public BaseAPI
         stepBuilder.add_rotary_pronunciation(rotary_pronunciation_string);
         stepBuilder.add_intersections(intersections_vector);
         stepBuilder.add_maneuver(maneuver_buffer);
-        mapbox::util::apply_visitor(GeometryVisitor<fbresult::StepBuilder>(stepBuilder), geometry);
+        std::visit(GeometryVisitor<fbresult::StepBuilder>(stepBuilder), geometry);
         return stepBuilder.Finish();
     };
 

include/engine/api/table_api.hpp

@@ -50,14 +50,14 @@ class TableAPI final : public BaseAPI
                  const std::vector<TableCellRef> &fallback_speed_cells,
                  osrm::engine::api::ResultT &response) const
     {
-        if (response.is<flatbuffers::FlatBufferBuilder>())
+        if (std::holds_alternative<flatbuffers::FlatBufferBuilder>(response))
         {
-            auto &fb_result = response.get<flatbuffers::FlatBufferBuilder>();
+            auto &fb_result = std::get<flatbuffers::FlatBufferBuilder>(response);
             MakeResponse(tables, candidates, fallback_speed_cells, fb_result);
         }
         else
         {
-            auto &json_result = response.get<util::json::Object>();
+            auto &json_result = std::get<util::json::Object>(response);
             MakeResponse(tables, candidates, fallback_speed_cells, json_result);
         }
     }
@@ -377,7 +377,8 @@ class TableAPI final : public BaseAPI
                                return util::json::Value(
                                    util::json::Number(from_alias<double>(duration) / 10.));
                            });
-            json_table.values.push_back(std::move(json_row));
+
+            json_table.values.push_back(util::json::Value{json_row});
         }
         return json_table;
     }
@@ -406,7 +407,7 @@ class TableAPI final : public BaseAPI
                                return util::json::Value(util::json::Number(
                                    std::round(from_alias<double>(distance) * 10) / 10.));
                            });
-            json_table.values.push_back(std::move(json_row));
+            json_table.values.push_back(util::json::Value{json_row});
         }
         return json_table;
     }
@@ -415,15 +416,18 @@ class TableAPI final : public BaseAPI
     MakeEstimatesTable(const std::vector<TableCellRef> &fallback_speed_cells) const
     {
         util::json::Array json_table;
-        std::for_each(fallback_speed_cells.begin(),
-                      fallback_speed_cells.end(),
-                      [&](const auto &cell)
-                      {
-                          util::json::Array row;
-                          row.values.push_back(util::json::Number(cell.row));
-                          row.values.push_back(util::json::Number(cell.column));
-                          json_table.values.push_back(std::move(row));
-                      });
+        std::for_each(
+            fallback_speed_cells.begin(),
+            fallback_speed_cells.end(),
+            [&](const auto &cell)
+            {
+                util::json::Array row;
+                util::json::Value jCellRow{util::json::Number(static_cast<double>(cell.row))};
+                util::json::Value jCellColumn{util::json::Number(static_cast<double>(cell.column))};
+                row.values.push_back(jCellRow);
+                row.values.push_back(jCellColumn);
+                json_table.values.push_back(util::json::Value{row});
+            });
         return json_table;
     }