refactor map::route to extract (some) cost functions

src/active_item_cache.cpp

@@ -8,7 +8,7 @@
 #include "item_pocket.h"
 #include "safe_reference.h"
 
-float item_reference::spoil_multiplier()
+float item_reference::spoil_multiplier() const
 {
     return std::accumulate(
                pocket_chain.begin(), pocket_chain.end(), 1.0F,
@@ -17,7 +17,7 @@ float item_reference::spoil_multiplier()
     } );
 }
 
-bool item_reference::has_watertight_container()
+bool item_reference::has_watertight_container() const
 {
     return std::any_of(
                pocket_chain.begin(), pocket_chain.end(),

src/active_item_cache.h

@@ -21,8 +21,8 @@ struct item_reference {
     item *parent = nullptr;
     std::vector<item_pocket const *> pocket_chain;
 
-    float spoil_multiplier();
-    bool has_watertight_container();
+    float spoil_multiplier() const;
+    bool has_watertight_container() const;
 };
 
 enum class special_item_type : int {

src/map.h

@@ -101,6 +101,8 @@ template<typename T>
 struct weighted_int_list;
 struct field_proc_data;
 
+enum pf_special : int;
+
 using relic_procgen_id = string_id<relic_procgen_data>;
 
 class map_stack : public item_stack
@@ -737,6 +739,20 @@ class map
         // Get a straight route from f to t, only along non-rough terrain. Returns an empty vector
         // if that is not possible.
         std::vector<tripoint> straight_route( const tripoint &f, const tripoint &t ) const;
+    private:
+        // Pathfinding cost helper that computes the cost of moving into |p| from |cur|.
+        // Includes climbing, bashing and opening doors.
+        int cost_to_pass( const tripoint &cur, const tripoint &p, const pathfinding_settings &settings,
+                          pf_special p_special ) const;
+        // Pathfinding cost helper that computes the cost of moving into |p|
+        // from |cur| based on perceived danger.
+        // Includes moving through traps.
+        int cost_to_avoid( const tripoint &cur, const tripoint &p, const pathfinding_settings &settings,
+                           pf_special p_special ) const;
+        // Sum of cost_to_pass and cost_to_avoid.
+        int extra_cost( const tripoint &cur, const tripoint &p, const pathfinding_settings &settings,
+                        pf_special p_special ) const;
+    public:
 
         // Vehicles: Common to 2D and 3D
         VehicleList get_vehicles();