ENH: postProcess - updated app to update on mesh change instead of full clear out

applications/utilities/postProcessing/postProcess/postProcess.C

@@ -43,6 +43,7 @@ Description
 #include "pointFields.H"
 #include "uniformDimensionedFields.H"
 #include "fileFieldSelection.H"
+#include "mapPolyMesh.H"
 
 using namespace Foam;
 
@@ -201,18 +202,31 @@ int main(int argc, char *argv[])
 
         Info<< "Time = " << runTime.timeName() << endl;
 
-        if (mesh.readUpdate() != polyMesh::UNCHANGED)
+        switch (mesh.readUpdate())
         {
-            // Update functionObjectList if mesh changes
-            // Note clearing the dictionary to avoid merge warning
-            functionsDict.clear();
-            functionsPtr = functionObjectList::New
-            (
-                args,
-                runTime,
-                functionsDict,
-                fieldFilters
-            );
+            case polyMesh::POINTS_MOVED:
+            {
+                functionsPtr->movePoints(mesh);
+                break;
+            }
+            case polyMesh::TOPO_CHANGE:
+            case polyMesh::TOPO_PATCH_CHANGE:
+            {
+                mapPolyMesh mpm(mesh);
+                functionsPtr->updateMesh(mpm);
+                break;
+            }
+            case polyMesh::UNCHANGED:
+            {
+                // No additional work
+                break;
+            }
+            default:
+            {
+                FatalErrorIn(args.executable())
+                    << "Unhandled enumeration"
+                    << abort(FatalError);
+            }
         }
 
         fields.resetFieldFilters(fieldFilters);