Return empty path when navmesh is not found for agent

apps/openmw_test_suite/detournavigator/navigator.cpp

@@ -65,9 +65,10 @@ namespace
         }
     };
 
-    TEST_F(DetourNavigatorNavigatorTest, find_path_for_empty_should_throw_exception)
+    TEST_F(DetourNavigatorNavigatorTest, find_path_for_empty_should_return_empty)
     {
-        EXPECT_THROW(mNavigator->findPath(mAgentHalfExtents, mStart, mEnd, Flag_walk, mOut), InvalidArgument);
+        mNavigator->findPath(mAgentHalfExtents, mStart, mEnd, Flag_walk, mOut);
+        EXPECT_EQ(mPath, std::deque<osg::Vec3f>());
     }
 
     TEST_F(DetourNavigatorNavigatorTest, find_path_for_existing_agent_with_no_navmesh_should_throw_exception)
@@ -76,11 +77,12 @@ namespace
         EXPECT_THROW(mNavigator->findPath(mAgentHalfExtents, mStart, mEnd, Flag_walk, mOut), NavigatorException);
     }
 
-    TEST_F(DetourNavigatorNavigatorTest, find_path_for_removed_agent_should_throw_exception)
+    TEST_F(DetourNavigatorNavigatorTest, find_path_for_removed_agent_should_return_empty)
     {
         mNavigator->addAgent(mAgentHalfExtents);
         mNavigator->removeAgent(mAgentHalfExtents);
-        EXPECT_THROW(mNavigator->findPath(mAgentHalfExtents, mStart, mEnd, Flag_walk, mOut), InvalidArgument);
+        mNavigator->findPath(mAgentHalfExtents, mStart, mEnd, Flag_walk, mOut);
+        EXPECT_EQ(mPath, std::deque<osg::Vec3f>());
     }
 
     TEST_F(DetourNavigatorNavigatorTest, add_agent_should_count_each_agent)

components/detournavigator/navigator.hpp

@@ -171,6 +171,8 @@ namespace DetourNavigator
                 "out is not an OutputIterator"
             );
             const auto navMesh = getNavMesh(agentHalfExtents);
+            if (!navMesh)
+                return out;
             const auto settings = getSettings();
             return findSmoothPath(navMesh.lock()->getValue(), toNavMeshCoordinates(settings, agentHalfExtents),
                 toNavMeshCoordinates(settings, start), toNavMeshCoordinates(settings, end), includeFlags,

components/detournavigator/navmeshmanager.cpp

@@ -133,7 +133,13 @@ namespace DetourNavigator
         else
             lastPlayerTile->second = playerTile;
         std::map<TilePosition, ChangeType> tilesToPost;
-        const auto& cached = getCached(agentHalfExtents);
+        const auto cached = getCached(agentHalfExtents);
+        if (!cached)
+        {
+            std::ostringstream stream;
+            stream << "Agent with half extents is not found: " << agentHalfExtents;
+            throw InvalidArgument(stream.str());
+        }
         const auto changedTiles = mChangedTiles.find(agentHalfExtents);
         {
             const auto locked = cached.lock();
@@ -218,13 +224,11 @@ namespace DetourNavigator
         }
     }
 
-    const SharedNavMeshCacheItem& NavMeshManager::getCached(const osg::Vec3f& agentHalfExtents) const
+    SharedNavMeshCacheItem NavMeshManager::getCached(const osg::Vec3f& agentHalfExtents) const
     {
         const auto cached = mCache.find(agentHalfExtents);
         if (cached != mCache.end())
             return cached->second;
-        std::ostringstream stream;
-        stream << "Agent with half extents is not found: " << agentHalfExtents;
-        throw InvalidArgument(stream.str());
+        return SharedNavMeshCacheItem();
     }
 }

components/detournavigator/navmeshmanager.hpp

@@ -67,7 +67,7 @@ namespace DetourNavigator
 
         void addChangedTile(const TilePosition& tilePosition, const ChangeType changeType);
 
-        const SharedNavMeshCacheItem& getCached(const osg::Vec3f& agentHalfExtents) const;
+        SharedNavMeshCacheItem getCached(const osg::Vec3f& agentHalfExtents) const;
     };
 }
 

components/misc/guarded.hpp

@@ -106,6 +106,11 @@ namespace Misc
                 return Locked<const T>(*mMutex, *mValue);
             }
 
+            operator bool() const
+            {
+                return static_cast<bool>(mValue);
+            }
+
         private:
             std::shared_ptr<std::mutex> mMutex;
             std::shared_ptr<T> mValue;