From b22ecba17983469d11cd39789a570c5938b9b4c0 Mon Sep 17 00:00:00 2001
From: Richard Brice <37087370+RickBrice@users.noreply.github.com>
Date: Wed, 31 Jul 2024 15:54:41 -0700
Subject: [PATCH] Implements mutually exclusive access to mapping cache with a
 mutex

---
 src/ifcgeom/mapping/mapping.cpp | 4 +++-
 src/ifcgeom/mapping/mapping.h   | 3 +++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/ifcgeom/mapping/mapping.cpp b/src/ifcgeom/mapping/mapping.cpp
index d9d140dc54..1fbd73d0c7 100644
--- a/src/ifcgeom/mapping/mapping.cpp
+++ b/src/ifcgeom/mapping/mapping.cpp
@@ -612,6 +612,7 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcStyledItem* inst) {
 taxonomy::ptr mapping::map(const IfcBaseInterface* inst) {
     auto iden = inst->as<IfcUtil::IfcBaseClass>()->identity();
     if (use_caching_) {
+        std::lock_guard<std::mutex> guard(cache_guard_);
         auto it = cache_.find(iden);
         if (it != cache_.end()) {
             return it->second;
@@ -629,7 +630,8 @@ taxonomy::ptr mapping::map(const IfcBaseInterface* inst) {
 
     if (item) {
         if (use_caching_) {
-            cache_.insert({ iden, item });
+            std::lock_guard<std::mutex> guard(cache_guard_);
+            cache_.insert({iden, item});
         }
     } else if (!matched) {
         Logger::Message(Logger::LOG_ERROR, "No operation defined for:", inst);
diff --git a/src/ifcgeom/mapping/mapping.h b/src/ifcgeom/mapping/mapping.h
index 1111101bb6..ace92a2276 100644
--- a/src/ifcgeom/mapping/mapping.h
+++ b/src/ifcgeom/mapping/mapping.h
@@ -6,6 +6,8 @@
 #include "../../ifcparse/IfcFile.h"
 #include "../../ifcparse/IfcLogger.h"
 
+#include <mutex>
+
 #define INCLUDE_SCHEMA(x) STRINGIFY(../../ifcparse/x.h)
 #include INCLUDE_SCHEMA(IfcSchema)
 #undef INCLUDE_SCHEMA
@@ -24,6 +26,7 @@ namespace geometry {
 		std::string length_unit_name_;
 
 		std::map<uint32_t, ifcopenshell::geometry::taxonomy::ptr> cache_;
+      std::mutex cache_guard_; // provides mutually exclusive access to cache_
 
 		const IfcParse::declaration* placement_rel_to_type_;
 		const IfcUtil::IfcBaseEntity* placement_rel_to_instance_;