From 90c6a57e0b62187dc93e3d84c8357f9630af4654 Mon Sep 17 00:00:00 2001
From: Tolu Okusanya <tookusa@sandia.gov>
Date: Thu, 14 Nov 2024 15:21:00 -0700
Subject: [PATCH] DTIO: Update to allow app the opportunity to clean up any
 data associated with a Region to prevent memory leaks

This happens when the Region is reset on a topology change
---
 .../ioss/src/Ioss_DynamicTopologyObserver.C   |  7 +++++++
 .../ioss/src/Ioss_DynamicTopologyObserver.h   |  2 ++
 .../seacas/libraries/ioss/src/Ioss_Region.C   | 20 +++++++++++++++----
 .../seacas/libraries/ioss/src/Ioss_Region.h   |  1 +
 4 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/packages/seacas/libraries/ioss/src/Ioss_DynamicTopologyObserver.C b/packages/seacas/libraries/ioss/src/Ioss_DynamicTopologyObserver.C
index abd55e68a4..9e3bf53936 100644
--- a/packages/seacas/libraries/ioss/src/Ioss_DynamicTopologyObserver.C
+++ b/packages/seacas/libraries/ioss/src/Ioss_DynamicTopologyObserver.C
@@ -212,4 +212,11 @@ namespace Ioss {
 
   void DynamicTopologyObserver::define_transient() {}
 
+  void DynamicTopologyObserver::initialize_region()
+  {
+    if (nullptr != m_region) {
+      m_region->reset_region();
+    }
+  }
+
 } // namespace Ioss
diff --git a/packages/seacas/libraries/ioss/src/Ioss_DynamicTopologyObserver.h b/packages/seacas/libraries/ioss/src/Ioss_DynamicTopologyObserver.h
index 65530994bc..90e4f12d93 100644
--- a/packages/seacas/libraries/ioss/src/Ioss_DynamicTopologyObserver.h
+++ b/packages/seacas/libraries/ioss/src/Ioss_DynamicTopologyObserver.h
@@ -70,6 +70,8 @@ namespace Ioss {
 
     virtual bool needs_new_output_file() const;
 
+    virtual void initialize_region();
+
   protected:
     Region      *m_region{nullptr};
     unsigned int m_topologyModification{TOPOLOGY_SAME};
diff --git a/packages/seacas/libraries/ioss/src/Ioss_Region.C b/packages/seacas/libraries/ioss/src/Ioss_Region.C
index 536608ee66..0dea284642 100644
--- a/packages/seacas/libraries/ioss/src/Ioss_Region.C
+++ b/packages/seacas/libraries/ioss/src/Ioss_Region.C
@@ -2897,7 +2897,8 @@ namespace Ioss {
 
       state++; // For the state we are going to write.
 
-      reset_region();
+      topologyObserver->initialize_region();
+
       DynamicTopologyFileControl fileControl(this);
       fileControl.add_output_database_change_set(state);
 
@@ -2939,7 +2940,8 @@ namespace Ioss {
 
       state++; // For the state we are going to write.
 
-      reset_region();
+      topologyObserver->initialize_region();
+
       DynamicTopologyFileControl fileControl(this);
       fileControl.clone_and_replace_output_database(state);
 
@@ -2982,7 +2984,12 @@ namespace Ioss {
     if (!iodatabase->open_internal_change_set(set_name))
       return false;
 
-    reset_region();
+    if(topologyObserver) {
+      topologyObserver->initialize_region();
+    } else {
+      reset_region();
+    }
+
     iodatabase->release_memory();
 
     Region::set_state(STATE_CLOSED);
@@ -3012,7 +3019,12 @@ namespace Ioss {
     if (!iodatabase->open_internal_change_set(child_group_index))
       return false;
 
-    reset_region();
+    if(topologyObserver) {
+      topologyObserver->initialize_region();
+    } else {
+      reset_region();
+    }
+
     iodatabase->release_memory();
 
     Region::set_state(STATE_CLOSED);
diff --git a/packages/seacas/libraries/ioss/src/Ioss_Region.h b/packages/seacas/libraries/ioss/src/Ioss_Region.h
index a17b12ae47..c924ec1f93 100644
--- a/packages/seacas/libraries/ioss/src/Ioss_Region.h
+++ b/packages/seacas/libraries/ioss/src/Ioss_Region.h
@@ -328,6 +328,7 @@ namespace Ioss {
 
     IOSS_NODISCARD std::tuple<std::string, int, double> locate_db_state(double targetTime) const;
 
+    // Reinitialize region data structures
     void reset_region();
 
   protected: