Passed ResultT down to engine plugins, so now they can form replies in different formats.

include/engine/api/base_result.hpp

@@ -0,0 +1,21 @@
+#ifndef ENGINE_API_BASE_RESULT_HPP
+#define ENGINE_API_BASE_RESULT_HPP
+
+#include <mapbox/variant.hpp>
+
+#include <string>
+
+#include "util/json_container.hpp"
+
+namespace osrm
+{
+namespace engine
+{
+namespace api
+{
+    using ResultT = mapbox::util::variant<util::json::Object, std::string>;
+} // ns api
+} // ns engine
+} // ns osrm
+
+#endif

include/engine/engine.hpp

@@ -33,16 +33,17 @@ class EngineInterface
   public:
     virtual ~EngineInterface() = default;
     virtual Status Route(const api::RouteParameters &parameters,
-                         util::json::Object &result) const = 0;
+                         api::ResultT &result) const = 0;
     virtual Status Table(const api::TableParameters &parameters,
-                         util::json::Object &result) const = 0;
+                         api::ResultT &result) const = 0;
     virtual Status Nearest(const api::NearestParameters &parameters,
-                           util::json::Object &result) const = 0;
+                           api::ResultT &result) const = 0;
     virtual Status Trip(const api::TripParameters &parameters,
-                        util::json::Object &result) const = 0;
+                        api::ResultT &result) const = 0;
     virtual Status Match(const api::MatchParameters &parameters,
-                         util::json::Object &result) const = 0;
-    virtual Status Tile(const api::TileParameters &parameters, std::string &result) const = 0;
+                         api::ResultT &result) const = 0;
+    virtual Status Tile(const api::TileParameters &parameters,
+                        api::ResultT &result) const = 0;
 };
 
 template <typename Algorithm> class Engine final : public EngineInterface
@@ -90,35 +91,37 @@ template <typename Algorithm> class Engine final : public EngineInterface
     virtual ~Engine() = default;
 
     Status Route(const api::RouteParameters &params,
-                 util::json::Object &result) const override final
+                 api::ResultT &result) const override final
     {
         return route_plugin.HandleRequest(GetAlgorithms(params), params, result);
     }
 
     Status Table(const api::TableParameters &params,
-                 util::json::Object &result) const override final
+                 api::ResultT &result) const override final
     {
         return table_plugin.HandleRequest(GetAlgorithms(params), params, result);
     }
 
     Status Nearest(const api::NearestParameters &params,
-                   util::json::Object &result) const override final
+                   api::ResultT &result) const override final
     {
         return nearest_plugin.HandleRequest(GetAlgorithms(params), params, result);
     }
 
-    Status Trip(const api::TripParameters &params, util::json::Object &result) const override final
+    Status Trip(const api::TripParameters &params,
+                api::ResultT &result) const override final
     {
         return trip_plugin.HandleRequest(GetAlgorithms(params), params, result);
     }
 
     Status Match(const api::MatchParameters &params,
-                 util::json::Object &result) const override final
+                 api::ResultT &result) const override final
     {
         return match_plugin.HandleRequest(GetAlgorithms(params), params, result);
     }
 
-    Status Tile(const api::TileParameters &params, std::string &result) const override final
+    Status Tile(const api::TileParameters &params,
+                api::ResultT &result) const override final
     {
         return tile_plugin.HandleRequest(GetAlgorithms(params), params, result);
     }

include/engine/plugins/match.hpp

@@ -32,7 +32,7 @@ class MatchPlugin : public BasePlugin
 
     Status HandleRequest(const RoutingAlgorithmsInterface &algorithms,
                          const api::MatchParameters &parameters,
-                         util::json::Object &json_result) const;
+                         osrm::engine::api::ResultT &json_result) const;
 
   private:
     const int max_locations_map_matching;

include/engine/plugins/nearest.hpp

@@ -21,7 +21,7 @@ class NearestPlugin final : public BasePlugin
 
     Status HandleRequest(const RoutingAlgorithmsInterface &algorithms,
                          const api::NearestParameters &params,
-                         util::json::Object &result) const;
+                         osrm::engine::api::ResultT &result) const;
 
   private:
     const int max_results;

include/engine/plugins/plugin_base.hpp

@@ -2,6 +2,7 @@
 #define BASE_PLUGIN_HPP
 
 #include "engine/api/base_parameters.hpp"
+#include "engine/api/base_result.hpp"
 #include "engine/datafacade/datafacade_base.hpp"
 #include "engine/phantom_node.hpp"
 #include "engine/routing_algorithms.hpp"
@@ -39,7 +40,7 @@ class BasePlugin
 
     bool CheckAlgorithms(const api::BaseParameters &params,
                          const RoutingAlgorithmsInterface &algorithms,
-                         util::json::Object &result) const
+                         osrm::engine::api::ResultT &result) const
     {
         if (algorithms.IsValid())
         {
@@ -64,8 +65,10 @@ class BasePlugin
 
     Status Error(const std::string &code,
                  const std::string &message,
-                 util::json::Object &json_result) const
+                 osrm::engine::api::ResultT &result) const
     {
+        result = util::json::Object();
+        auto& json_result = result.get<util::json::Object>();
         json_result.values["code"] = code;
         json_result.values["message"] = message;
         return Status::Error;

include/engine/plugins/table.hpp

@@ -22,7 +22,7 @@ class TablePlugin final : public BasePlugin
 
     Status HandleRequest(const RoutingAlgorithmsInterface &algorithms,
                          const api::TableParameters &params,
-                         util::json::Object &result) const;
+                         osrm::engine::api::ResultT &result) const;
 
   private:
     const int max_locations_distance_table;

include/engine/plugins/tile.hpp

@@ -28,7 +28,7 @@ class TilePlugin final : public BasePlugin
   public:
     Status HandleRequest(const RoutingAlgorithmsInterface &algorithms,
                          const api::TileParameters &parameters,
-                         std::string &pbf_buffer) const;
+                         osrm::engine::api::ResultT &pbf_buffer) const;
 };
 }
 }

include/engine/plugins/trip.hpp

@@ -40,7 +40,7 @@ class TripPlugin final : public BasePlugin
 
     Status HandleRequest(const RoutingAlgorithmsInterface &algorithms,
                          const api::TripParameters &parameters,
-                         util::json::Object &json_result) const;
+                         osrm::engine::api::ResultT &json_result) const;
 };
 }
 }

include/engine/plugins/viaroute.hpp

@@ -33,7 +33,7 @@ class ViaRoutePlugin final : public BasePlugin
 
     Status HandleRequest(const RoutingAlgorithmsInterface &algorithms,
                          const api::RouteParameters &route_parameters,
-                         util::json::Object &json_result) const;
+                         osrm::engine::api::ResultT &json_result) const;
 };
 }
 }