Cleanup: IO: Various cleanups for the AbstractHierarchyIterator

Various non-functional cleanups for the AbstractHierarchyIterator.
- Use const in more places
- Remove unused headers

Pull Request: https://projects.blender.org/blender/blender/pulls/140508

source/blender/io/common/IO_abstract_hierarchy_iterator.h

@@ -299,7 +299,7 @@ class AbstractHierarchyIterator {
   void export_graph_clear();
 
   void visit_object(Object *object, Object *export_parent, bool weak_export);
-  void visit_dupli_object(DupliObject *dupli_object,
+  void visit_dupli_object(const DupliObject *dupli_object,
                           Object *duplicator,
                           const DupliParentFinder &dupli_parent_finder);
 
@@ -320,7 +320,7 @@ class AbstractHierarchyIterator {
   HierarchyContext context_for_object_data(const HierarchyContext *object_context) const;
 
   /* Convenience wrappers around get_id_name(). */
-  std::string get_object_name(const Object *object);
+  std::string get_object_name(const Object *object) const;
   std::string get_object_name(const Object *object, const Object *parent);
   std::string get_object_data_name(const Object *object) const;
 
@@ -330,7 +330,7 @@ class AbstractHierarchyIterator {
    *
    * The create_func function should be one of the create_XXXX_writer(context) functions declared
    * below. */
-  EnsuredWriter ensure_writer(HierarchyContext *context, create_writer_func create_func);
+  EnsuredWriter ensure_writer(const HierarchyContext *context, create_writer_func create_func);
 
  protected:
   /* Construct a valid path for the export file format. This class concatenates by using '/' as a

source/blender/io/common/intern/abstract_hierarchy_iterator.cc

@@ -10,15 +10,13 @@
 
 #include "BKE_anim_data.hh"
 #include "BKE_duplilist.hh"
+#include "BKE_geometry_set.hh"
 #include "BKE_geometry_set_instances.hh"
 #include "BKE_key.hh"
-#include "BKE_modifier.hh"
-#include "BKE_node_legacy_types.hh"
 #include "BKE_object.hh"
 #include "BKE_particle.h"
 
 #include "BLI_assert.h"
-#include "BLI_listbase.h"
 #include "BLI_math_matrix.h"
 #include "BLI_set.hh"
 #include "BLI_string_utils.hh"
@@ -26,7 +24,6 @@
 #include "DNA_ID.h"
 #include "DNA_layer_types.h"
 #include "DNA_modifier_types.h"
-#include "DNA_node_types.h"
 #include "DNA_object_types.h"
 #include "DNA_particle_types.h"
 #include "DNA_rigidbody_types.h"
@@ -322,7 +319,7 @@ void AbstractHierarchyIterator::export_graph_construct()
     if (!duplilist.is_empty()) {
       DupliParentFinder dupli_parent_finder;
 
-      for (DupliObject &dupli_object : duplilist) {
+      for (const DupliObject &dupli_object : duplilist) {
         PersistentID persistent_id(&dupli_object);
         if (!should_visit_dupli_object(&dupli_object)) {
           continue;
@@ -330,7 +327,7 @@ void AbstractHierarchyIterator::export_graph_construct()
         dupli_parent_finder.insert(&dupli_object);
       }
 
-      for (DupliObject &dupli_object : duplilist) {
+      for (const DupliObject &dupli_object : duplilist) {
         if (!should_visit_dupli_object(&dupli_object)) {
           continue;
         }
@@ -469,7 +466,7 @@ ObjectIdentifier AbstractHierarchyIterator::determine_graph_index_object(
   return ObjectIdentifier::for_real_object(context->export_parent);
 }
 
-void AbstractHierarchyIterator::visit_dupli_object(DupliObject *dupli_object,
+void AbstractHierarchyIterator::visit_dupli_object(const DupliObject *dupli_object,
                                                    Object *duplicator,
                                                    const DupliParentFinder &dupli_parent_finder)
 {
@@ -648,12 +645,15 @@ void AbstractHierarchyIterator::make_writers(const HierarchyContext *parent_cont
     return;
   }
 
+  bool has_point_instance_ancestor = false;
+  if (parent_context &&
+      (parent_context->is_point_instance || parent_context->has_point_instance_ancestor))
+  {
+    has_point_instance_ancestor = true;
+  }
+
   for (HierarchyContext *context : *children) {
-    if (parent_context) {
-      if (parent_context->is_point_instance || parent_context->has_point_instance_ancestor) {
-        context->has_point_instance_ancestor = true;
-      }
-    }
+    context->has_point_instance_ancestor = has_point_instance_ancestor;
 
     /* Update the context so that it is correct for this parent-child relation. */
     copy_m4_m4(context->parent_matrix_inv_world, parent_matrix_inv_world);
@@ -787,7 +787,7 @@ void AbstractHierarchyIterator::make_writers_particle_systems(
   }
 }
 
-std::string AbstractHierarchyIterator::get_object_name(const Object *object)
+std::string AbstractHierarchyIterator::get_object_name(const Object *object) const
 {
   return get_id_name(&object->id);
 }
@@ -800,7 +800,7 @@ std::string AbstractHierarchyIterator::get_object_name(const Object *object, con
 
 std::string AbstractHierarchyIterator::get_object_data_name(const Object *object) const
 {
-  ID *object_data = static_cast<ID *>(object->data);
+  const ID *object_data = static_cast<ID *>(object->data);
   return get_id_name(object_data);
 }
 
@@ -811,7 +811,7 @@ AbstractHierarchyWriter *AbstractHierarchyIterator::get_writer(
 }
 
 EnsuredWriter AbstractHierarchyIterator::ensure_writer(
-    HierarchyContext *context, AbstractHierarchyIterator::create_writer_func create_func)
+    const HierarchyContext *context, AbstractHierarchyIterator::create_writer_func create_func)
 {
   AbstractHierarchyWriter *writer = get_writer(context->export_path);
   if (writer != nullptr) {