From 9d61c494789749f1b3cda43f008920af6bf2177a Mon Sep 17 00:00:00 2001
From: elsid <elsid.mail@gmail.com>
Date: Sun, 10 Mar 2019 20:28:33 +0300
Subject: [PATCH] Store key by reference in tiles map

---
 components/detournavigator/navmeshtilescache.cpp | 10 +++++-----
 components/detournavigator/navmeshtilescache.hpp | 16 +++++++++++++++-
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/components/detournavigator/navmeshtilescache.cpp b/components/detournavigator/navmeshtilescache.cpp
index 418e69e824..51450cdbd1 100644
--- a/components/detournavigator/navmeshtilescache.cpp
+++ b/components/detournavigator/navmeshtilescache.cpp
@@ -85,7 +85,7 @@ namespace DetourNavigator
         if (navMeshSize > mFreeNavMeshDataSize + (mMaxNavMeshDataSize - mUsedNavMeshDataSize))
             return Value();
 
-        const auto navMeshKey = makeNavMeshKey(recastMesh, offMeshConnections);
+        auto navMeshKey = makeNavMeshKey(recastMesh, offMeshConnections);
         const auto itemSize = navMeshSize + 2 * navMeshKey.size();
 
         if (itemSize > mFreeNavMeshDataSize + (mMaxNavMeshDataSize - mUsedNavMeshDataSize))
@@ -94,9 +94,8 @@ namespace DetourNavigator
         while (!mFreeItems.empty() && mUsedNavMeshDataSize + itemSize > mMaxNavMeshDataSize)
             removeLeastRecentlyUsed();
 
-        const auto iterator = mFreeItems.emplace(mFreeItems.end(), agentHalfExtents, changedTile, navMeshKey);
-        // TODO: use std::string_view or some alternative to avoid navMeshKey copy into both mFreeItems and mValues
-        const auto emplaced = mValues[agentHalfExtents][changedTile].mMap.emplace(navMeshKey, iterator);
+        const auto iterator = mFreeItems.emplace(mFreeItems.end(), agentHalfExtents, changedTile, std::move(navMeshKey));
+        const auto emplaced = mValues[agentHalfExtents][changedTile].mMap.emplace(iterator->mNavMeshKey, iterator);
 
         if (!emplaced.second)
         {
@@ -131,9 +130,10 @@ namespace DetourNavigator
 
         mUsedNavMeshDataSize -= getSize(item);
         mFreeNavMeshDataSize -= getSize(item);
-        mFreeItems.pop_back();
 
         tileValues->second.mMap.erase(value);
+        mFreeItems.pop_back();
+
         if (!tileValues->second.mMap.empty())
             return;
 
diff --git a/components/detournavigator/navmeshtilescache.hpp b/components/detournavigator/navmeshtilescache.hpp
index e244cda9d7..6c57f7563c 100644
--- a/components/detournavigator/navmeshtilescache.hpp
+++ b/components/detournavigator/navmeshtilescache.hpp
@@ -105,10 +105,24 @@ namespace DetourNavigator
             NavMeshData&& value);
 
     private:
+        class KeyView
+        {
+        public:
+            KeyView(const std::string& value)
+                : mValue(value) {}
+
+            friend bool operator <(const KeyView& lhs, const KeyView& rhs)
+            {
+                return lhs.mValue.get() < rhs.mValue.get();
+            }
+
+        private:
+            std::reference_wrapper<const std::string> mValue;
+        };
 
         struct TileMap
         {
-            std::map<std::string, ItemIterator> mMap;
+            std::map<KeyView, ItemIterator> mMap;
         };
 
         std::mutex mMutex;