[traffxml] Add router-based decoder, still crude, ugly and buggy

To use it, redefine DefaultTraffDecoder in traffxml/traff_decoder.hpp

Signed-off-by: mvglasow <michael -at- vonglasow.com>

routing/index_router.hpp

@@ -65,6 +65,23 @@ public:
     m2::PointD const m_direction;
   };
 
+  /**
+   * @brief Creates a new `IndexRouter` instance.
+   *
+   * This is the constructor intended for normal routing. It requires a `TrafficCache` argument,
+   * from which it may create a traffic stash so the traffic situation can be considered for the
+   * route, depending on the vehicle type.
+   *
+   * @param vehicleType The vehichle type
+   * @param loadAltitudes Whether to load altitudes
+   * @param countryParentNameGetterFn Function which converts a country name into the name of its parent country)
+   * @param countryFileFn Function which converts a pointer to its country name
+   * @param countryRectFn Function which returns the rect for a country
+   * @param numMwmIds
+   * @param numMwmTree
+   * @param trafficCache The traffic cache (used only if `vehicleType` is `VehicleType::Car`)
+   * @param dataSource The MWM data source
+   */
   IndexRouter(VehicleType vehicleType, bool loadAltitudes,
               CountryParentNameGetterFn const & countryParentNameGetterFn,
               TCountryFileFn const & countryFileFn, CountryRectFn const & countryRectFn,
@@ -89,6 +106,29 @@ public:
 
   VehicleType GetVehicleType() const { return m_vehicleType; }
 
+protected:
+  /**
+   * @brief Creates a new `IndexRouter` instance.
+   *
+   * This constructor is intended for use by the TraFF decoder, not for normal routing. It lacks the
+   * `TrafficCache` argument and never creates a traffic stash. This creates a router instance which
+   * ignores the traffic situation, regardless of the vehicle type.
+   *
+   * @param vehicleType The vehichle type
+   * @param loadAltitudes Whether to load altitudes
+   * @param countryParentNameGetterFn Function which converts a country name into the name of its parent country)
+   * @param countryFileFn Function which converts a pointer to its country name
+   * @param countryRectFn Function which returns the rect for a country
+   * @param numMwmIds
+   * @param numMwmTree
+   * @param dataSource The MWM data source
+   */
+  IndexRouter(VehicleType vehicleType, bool loadAltitudes,
+              CountryParentNameGetterFn const & countryParentNameGetterFn,
+              TCountryFileFn const & countryFileFn, CountryRectFn const & countryRectFn,
+              std::shared_ptr<NumMwmIds> numMwmIds, std::unique_ptr<m4::Tree<NumMwmId>> numMwmTree,
+              DataSource & dataSource);
+
 private:
   RouterResultCode CalculateSubrouteJointsMode(IndexGraphStarter & starter,
                                                RouterDelegate const & delegate,