Add support of custom ServiceHandler

include/server/request_handler.hpp

@@ -24,12 +24,12 @@ class RequestHandler
     RequestHandler(const RequestHandler &) = delete;
     RequestHandler &operator=(const RequestHandler &) = delete;
 
-    void RegisterServiceHandler(std::unique_ptr<ServiceHandler> service_handler);
+    void RegisterServiceHandler(std::unique_ptr<ServiceHandlerInterface> service_handler);
 
     void HandleRequest(const http::request &current_request, http::reply &current_reply);
 
   private:
-    std::unique_ptr<ServiceHandler> service_handler;
+    std::unique_ptr<ServiceHandlerInterface> service_handler;
 };
 }
 }

include/server/server.hpp

@@ -86,7 +86,7 @@ class Server
 
     void Stop() { io_service.stop(); }
 
-    void RegisterServiceHandler(std::unique_ptr<ServiceHandler> service_handler_)
+    void RegisterServiceHandler(std::unique_ptr<ServiceHandlerInterface> service_handler_)
     {
         request_handler.RegisterServiceHandler(std::move(service_handler_));
     }

include/server/service_handler.hpp

@@ -23,13 +23,21 @@ namespace api
 struct ParsedURL;
 }
 
-class ServiceHandler
+
+class ServiceHandlerInterface
+{
+public:
+    virtual ~ServiceHandlerInterface() {}
+    virtual engine::Status RunQuery(api::ParsedURL parsed_url, service::BaseService::ResultT & result) = 0;
+};
+
+class ServiceHandler final : public ServiceHandlerInterface
 {
   public:
     ServiceHandler(osrm::EngineConfig &config);
     using ResultT = service::BaseService::ResultT;
 
-    engine::Status RunQuery(api::ParsedURL parsed_url, ResultT &result);
+    virtual engine::Status RunQuery(api::ParsedURL parsed_url, ResultT &result) override;
 
   private:
     std::unordered_map<std::string, std::unique_ptr<service::BaseService>> service_map;

src/server/request_handler.cpp

@@ -30,7 +30,7 @@ namespace osrm
 namespace server
 {
 
-void RequestHandler::RegisterServiceHandler(std::unique_ptr<ServiceHandler> service_handler_)
+void RequestHandler::RegisterServiceHandler(std::unique_ptr<ServiceHandlerInterface> service_handler_)
 {
     service_handler = std::move(service_handler_);
 }