Core/Misc: Make VMapManager2::acquireModelInstance and releaseModelInstance thread safe

Closes #4086

src/server/collision/Management/VMapManager2.cpp

@@ -247,6 +247,9 @@ namespace VMAP
 
     WorldModel* VMapManager2::acquireModelInstance(const std::string& basepath, const std::string& filename)
     {
+        //! Critical section, thread safe access to iLoadedModelFiles
+        TRINITY_GUARD(ACE_Thread_Mutex, LoadedModelFilesLock);
+
         ModelFileMap::iterator model = iLoadedModelFiles.find(filename);
         if (model == iLoadedModelFiles.end())
         {
@@ -267,6 +270,9 @@ namespace VMAP
 
     void VMapManager2::releaseModelInstance(const std::string &filename)
     {
+        //! Critical section, thread safe access to iLoadedModelFiles
+        TRINITY_GUARD(ACE_Thread_Mutex, LoadedModelFilesLock);
+
         ModelFileMap::iterator model = iLoadedModelFiles.find(filename);
         if (model == iLoadedModelFiles.end())
         {

src/server/collision/Management/VMapManager2.h

@@ -22,6 +22,7 @@
 #include "IVMapManager.h"
 #include "Dynamic/UnorderedMap.h"
 #include "Define.h"
+#include <ace/Thread_Mutex.h>
 
 //===========================================================
 
@@ -71,6 +72,8 @@ namespace VMAP
             // Tree to check collision
             ModelFileMap iLoadedModelFiles;
             InstanceTreeMap iInstanceMapTrees;
+            // Mutex for iLoadedModelFiles
+            ACE_Thread_Mutex LoadedModelFilesLock;
 
             bool _loadMap(uint32 mapId, const std::string& basePath, uint32 tileX, uint32 tileY);
             /* void _unloadMap(uint32 pMapId, uint32 x, uint32 y); */