From 971e16413bd79bb74040563b167ee6009cd9106e Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Wed, 19 Jun 2024 12:13:33 +0100
Subject: [PATCH] Added mutex to FindDynamicObjects and PropagateDynamicObjects
 to avoid multiple threads using the same instances at the same time.

---
 include/vsg/utils/FindDynamicObjects.h      | 2 ++
 include/vsg/utils/PropagateDynamicObjects.h | 1 +
 src/vsg/io/read.cpp                         | 4 ++++
 3 files changed, 7 insertions(+)

diff --git a/include/vsg/utils/FindDynamicObjects.h b/include/vsg/utils/FindDynamicObjects.h
index 1fc167451..2e1427256 100644
--- a/include/vsg/utils/FindDynamicObjects.h
+++ b/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)
diff --git a/include/vsg/utils/PropagateDynamicObjects.h b/include/vsg/utils/PropagateDynamicObjects.h
index ccfde409a..4c60514f5 100644
--- a/include/vsg/utils/PropagateDynamicObjects.h
+++ b/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;
 
diff --git a/src/vsg/io/read.cpp b/src/vsg/io/read.cpp
index dca5a789b..cf578387c 100644
--- a/src/vsg/io/read.cpp
+++ b/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));