Added mutex to FindDynamicObjects and PropagateDynamicObjects to avoid multiple threads using the same instances at the same time.

Author: robertosfield

include/vsg/utils/FindDynamicObjects.h

@@ -24,6 +24,8 @@ namespace vsg
     class VSG_DECLSPEC FindDynamicObjects : public Inherit<ConstVisitor, FindDynamicObjects>
     {
     public:
+
+        std::mutex mutex;
         std::set<const Object*> dynamicObjects;
 
         inline void tag(const Object* object)

include/vsg/utils/PropagateDynamicObjects.h

@@ -26,6 +26,7 @@ namespace vsg
     public:
         PropagateDynamicObjects();
 
+        std::mutex mutex;
         std::set<const Object*> dynamicObjects;
         std::stack<bool> taggedStack;
 

src/vsg/io/read.cpp

@@ -77,9 +77,13 @@ ref_ptr<Object> vsg::read(const Path& filename, ref_ptr<const Options> options)
             if (load->object && options && options->findDynamicObjects && options->propagateDynamicObjects)
             {
                 // invoke the find and propogate visitiors to collate all the dynamic objects that will need to be cloned.
+
+                std::scoped_lock<std::mutex> fdo_lock(options->findDynamicObjects->mutex);
+
                 options->findDynamicObjects->dynamicObjects.clear();
                 load->object->accept(*(options->findDynamicObjects));
 
+                std::scoped_lock<std::mutex> pdo_lock(options->propagateDynamicObjects->mutex);
                 options->propagateDynamicObjects->dynamicObjects.swap(options->findDynamicObjects->dynamicObjects);
                 load->object->accept(*(options->propagateDynamicObjects));