AC_Fence: use number-of-items-loaded rather than fence-loaded

AC_Fence: fail prearms on zero items, not just fence-loaded

Co-authored-by: Andy Piper <[email protected]>

we fail to load the fence if the storage is invalid, but if it is just empty we will be marked as "loaded".

AC_Fence: never breach on zero items loaded

Co-authored-by: Andy Piper <[email protected]>

we can be loaded but with zero points

AC_Fence: remove unused loaded method

Co-authored-by: Andy Piper <[email protected]>

Author: peterbarker

libraries/AC_Fence/AC_Fence.cpp

@@ -274,7 +274,7 @@ bool AC_Fence::pre_arm_check_polygon(const char* &fail_msg) const
         return true;
     }
 
-    if (! _poly_loader.loaded()) {
+    if (_poly_loader.total_fence_count() == 0) {
         fail_msg = "Fences invalid";
         return false;
     }

libraries/AC_Fence/AC_PolyFence_loader.cpp

@@ -227,7 +227,7 @@ bool AC_PolyFence_loader::breached() const
 //   returns true if location is outside the boundary
 bool AC_PolyFence_loader::breached(const Location& loc) const
 {
-    if (!loaded()) {
+    if (total_fence_count() == 0) {
         return false;
     }
 

libraries/AC_Fence/AC_PolyFence_loader.h

@@ -140,12 +140,6 @@ class AC_PolyFence_loader
         return _num_loaded_inclusion_boundaries != 0;
     }
 
-    // loaded - returns true if the fences have been loaded from
-    // storage and are available for use
-    bool loaded() const WARN_IF_UNUSED {
-        return _load_time_ms != 0;
-    };
-
     // maximum number of fence points we can store in eeprom
     uint16_t max_items() const;