Cleanup: Follow C++ code style for new Outliner building code

See https://developer.blender.org/D9499.

* Use C++17 nested namespaces.
* Use `_` suffix rather than prefix for private member variables.

Also: Simplify code visually in `tree_view.cc` with `using namespace`.

4 files changed, 42 insertions, 56 deletions

diff --git a/source/blender/editors/space_outliner/tree/tree_view.cc b/source/blender/editors/space_outliner/tree/tree_view.cc
index f6c3da012f4..7eefae7124c 100644
--- a/source/blender/editors/space_outliner/tree/tree_view.cc
+++ b/source/blender/editors/space_outliner/tree/tree_view.cc
@@ -24,9 +24,7 @@
 
 #include "tree_view.hh"
 
-namespace outliner = blender::ed::outliner;
-/* Convenience. */
-using outliner::AbstractTreeView;
+using namespace blender::ed::outliner;
 
 TreeView *outliner_tree_view_create(eSpaceOutliner_Mode mode, SpaceOutliner *space_outliner)
 {
@@ -36,14 +34,14 @@ TreeView *outliner_tree_view_create(eSpaceOutliner_Mode mode, SpaceOutliner *spa
     case SO_SCENES:
       break;
     case SO_LIBRARIES:
-      tree_view = new outliner::TreeViewLibraries(*space_outliner);
+      tree_view = new TreeViewLibraries(*space_outliner);
       break;
     case SO_SEQUENCE:
     case SO_DATA_API:
     case SO_ID_ORPHANS:
       break;
     case SO_VIEW_LAYER:
-      tree_view = new outliner::TreeViewViewLayer(*space_outliner);
+      tree_view = new TreeViewViewLayer(*space_outliner);
       break;
   }
 
diff --git a/source/blender/editors/space_outliner/tree/tree_view.hh b/source/blender/editors/space_outliner/tree/tree_view.hh
index a9aed29abc1..63a0826b440 100644
--- a/source/blender/editors/space_outliner/tree/tree_view.hh
+++ b/source/blender/editors/space_outliner/tree/tree_view.hh
@@ -33,9 +33,7 @@ struct TreeSourceData;
 
 #ifdef __cplusplus
 
-namespace blender {
-namespace ed {
-namespace outliner {
+namespace blender::ed::outliner {
 
 /* -------------------------------------------------------------------- */
 /* Tree-View Interface */
@@ -50,7 +48,7 @@ namespace outliner {
  */
 class AbstractTreeView {
  public:
-  AbstractTreeView(SpaceOutliner &space_outliner) : _space_outliner(space_outliner)
+  AbstractTreeView(SpaceOutliner &space_outliner) : space_outliner_(space_outliner)
   {
   }
   virtual ~AbstractTreeView() = default;
@@ -63,7 +61,7 @@ class AbstractTreeView {
 
  protected:
   /** All derived classes will need a handle to this, so storing it in the base for convenience. */
-  SpaceOutliner &_space_outliner;
+  SpaceOutliner &space_outliner_;
 };
 
 /* -------------------------------------------------------------------- */
@@ -73,8 +71,8 @@ class AbstractTreeView {
  * \brief Tree-View for the View Layer display mode.
  */
 class TreeViewViewLayer final : public AbstractTreeView {
-  ViewLayer *_view_layer = nullptr;
-  bool _show_objects = true;
+  ViewLayer *view_layer_ = nullptr;
+  bool show_objects_ = true;
 
  public:
   TreeViewViewLayer(SpaceOutliner &space_outliner);
@@ -106,9 +104,7 @@ class TreeViewLibraries final : public AbstractTreeView {
   short id_filter_get() const;
 };
 
-}  // namespace outliner
-}  // namespace ed
-}  // namespace blender
+}  // namespace blender::ed::outliner
 
 extern "C" {
 #endif
diff --git a/source/blender/editors/space_outliner/tree/tree_view_libraries.cc b/source/blender/editors/space_outliner/tree/tree_view_libraries.cc
index 77fa1fd3990..bd75bba83eb 100644
--- a/source/blender/editors/space_outliner/tree/tree_view_libraries.cc
+++ b/source/blender/editors/space_outliner/tree/tree_view_libraries.cc
@@ -29,9 +29,7 @@
 #include "../outliner_intern.h"
 #include "tree_view.hh"
 
-namespace blender {
-namespace ed {
-namespace outliner {
+namespace blender::ed::outliner {
 
 /* Convenience/readability. */
 template<typename T> using List = ListBaseWrapper<T>;
@@ -114,7 +112,7 @@ TreeElement *TreeViewLibraries::add_library_contents(Main &mainvar,
   ListBase *lbarray[MAX_LIBARRAY];
   int tot;
   if (filter_id_type) {
-    lbarray[0] = which_libbase(&mainvar, _space_outliner.filter_id_type);
+    lbarray[0] = which_libbase(&mainvar, space_outliner_.filter_id_type);
     tot = 1;
   }
   else {
@@ -144,10 +142,10 @@ TreeElement *TreeViewLibraries::add_library_contents(Main &mainvar,
       if (!tenlib) {
         /* Create library tree element on demand, depending if there are any data-blocks. */
         if (lib) {
-          tenlib = outliner_add_element(&_space_outliner, &lb, lib, nullptr, 0, 0);
+          tenlib = outliner_add_element(&space_outliner_, &lb, lib, nullptr, 0, 0);
         }
         else {
-          tenlib = outliner_add_element(&_space_outliner, &lb, &mainvar, nullptr, TSE_ID_BASE, 0);
+          tenlib = outliner_add_element(&space_outliner_, &lb, &mainvar, nullptr, TSE_ID_BASE, 0);
           tenlib->name = IFACE_("Current File");
         }
       }
@@ -161,14 +159,14 @@ TreeElement *TreeViewLibraries::add_library_contents(Main &mainvar,
         }
         else {
           ten = outliner_add_element(
-              &_space_outliner, &tenlib->subtree, lbarray[a], nullptr, TSE_ID_BASE, 0);
+              &space_outliner_, &tenlib->subtree, lbarray[a], nullptr, TSE_ID_BASE, 0);
           ten->directdata = lbarray[a];
           ten->name = outliner_idcode_to_plural(GS(id->name));
         }
 
         for (ID *id : List<ID>(lbarray[a])) {
           if (library_id_filter_poll(lib, id)) {
-            outliner_add_element(&_space_outliner, &ten->subtree, id, ten, 0, 0);
+            outliner_add_element(&space_outliner_, &ten->subtree, id, ten, 0, 0);
           }
         }
       }
@@ -180,8 +178,8 @@ TreeElement *TreeViewLibraries::add_library_contents(Main &mainvar,
 
 short TreeViewLibraries::id_filter_get() const
 {
-  if (_space_outliner.filter & SO_FILTER_ID_TYPE) {
-    return _space_outliner.filter_id_type;
+  if (space_outliner_.filter & SO_FILTER_ID_TYPE) {
+    return space_outliner_.filter_id_type;
   }
   return 0;
 }
@@ -212,6 +210,4 @@ bool TreeViewLibraries::library_id_filter_poll(Library *lib, ID *id) const
   return true;
 }
 
-}  // namespace outliner
-}  // namespace ed
-}  // namespace blender
+}  // namespace blender::ed::outliner
diff --git a/source/blender/editors/space_outliner/tree/tree_view_view_layer.cc b/source/blender/editors/space_outliner/tree/tree_view_view_layer.cc
index abfce72d0fb..8895673f060 100644
--- a/source/blender/editors/space_outliner/tree/tree_view_view_layer.cc
+++ b/source/blender/editors/space_outliner/tree/tree_view_view_layer.cc
@@ -34,9 +34,7 @@
 #include "../outliner_intern.h"
 #include "tree_view.hh"
 
-namespace blender {
-namespace ed {
-namespace outliner {
+namespace blender::ed::outliner {
 
 /* Convenience/readability. */
 template<typename T> using List = ListBaseWrapper<T>;
@@ -45,8 +43,8 @@ class ObjectsChildrenBuilder {
   using TreeChildren = Vector<TreeElement *>;
   using ObjectTreeElementsMap = Map<Object *, TreeChildren>;
 
-  SpaceOutliner &_outliner;
-  ObjectTreeElementsMap _object_tree_elements_map;
+  SpaceOutliner &outliner_;
+  ObjectTreeElementsMap object_tree_elements_map_;
 
  public:
   ObjectsChildrenBuilder(SpaceOutliner &);
@@ -73,16 +71,16 @@ ListBase TreeViewViewLayer::buildTree(const TreeSourceData &source_data)
 {
   ListBase tree = {nullptr};
 
-  _view_layer = source_data.view_layer;
-  _show_objects = !(_space_outliner.filter & SO_FILTER_NO_OBJECT);
+  view_layer_ = source_data.view_layer;
+  show_objects_ = !(space_outliner_.filter & SO_FILTER_NO_OBJECT);
 
-  const bool show_children = (_space_outliner.filter & SO_FILTER_NO_CHILDREN) == 0;
+  const bool show_children = (space_outliner_.filter & SO_FILTER_NO_CHILDREN) == 0;
 
-  if (_space_outliner.filter & SO_FILTER_NO_COLLECTION) {
+  if (space_outliner_.filter & SO_FILTER_NO_COLLECTION) {
     /* Show objects in the view layer. */
-    for (Base *base : List<Base>(_view_layer->object_bases)) {
+    for (Base *base : List<Base>(view_layer_->object_bases)) {
       TreeElement *te_object = outliner_add_element(
-          &_space_outliner, &tree, base->object, nullptr, 0, 0);
+          &space_outliner_, &tree, base->object, nullptr, 0, 0);
       te_object->directdata = base;
     }
 
@@ -93,7 +91,7 @@ ListBase TreeViewViewLayer::buildTree(const TreeSourceData &source_data)
   else {
     /* Show collections in the view layer. */
     TreeElement &ten = *outliner_add_element(
-        &_space_outliner, &tree, source_data.scene, nullptr, TSE_VIEW_COLLECTION_BASE, 0);
+        &space_outliner_, &tree, source_data.scene, nullptr, TSE_VIEW_COLLECTION_BASE, 0);
     ten.name = IFACE_("Scene Collection");
     TREESTORE(&ten)->flag &= ~TSE_CLOSED;
 
@@ -109,13 +107,13 @@ ListBase TreeViewViewLayer::buildTree(const TreeSourceData &source_data)
 void TreeViewViewLayer::add_view_layer(ListBase &tree, TreeElement &parent)
 {
   /* First layer collection is for master collection, don't show it. */
-  LayerCollection *lc = static_cast<LayerCollection *>(_view_layer->layer_collections.first);
+  LayerCollection *lc = static_cast<LayerCollection *>(view_layer_->layer_collections.first);
   if (lc == nullptr) {
     return;
   }
 
   add_layer_collections_recursive(tree, lc->layer_collections, parent);
-  if (_show_objects) {
+  if (show_objects_) {
     add_layer_collection_objects(tree, *lc, parent);
   }
 }
@@ -128,13 +126,13 @@ void TreeViewViewLayer::add_layer_collections_recursive(ListBase &tree,
     const bool exclude = (lc->flag & LAYER_COLLECTION_EXCLUDE) != 0;
     TreeElement *ten;
 
-    if (exclude && ((_space_outliner.show_restrict_flags & SO_RESTRICT_ENABLE) == 0)) {
+    if (exclude && ((space_outliner_.show_restrict_flags & SO_RESTRICT_ENABLE) == 0)) {
       ten = &parent_ten;
     }
     else {
       ID *id = &lc->collection->id;
       ten = outliner_add_element(
-          &_space_outliner, &tree, id, &parent_ten, TSE_LAYER_COLLECTION, 0);
+          &space_outliner_, &tree, id, &parent_ten, TSE_LAYER_COLLECTION, 0);
 
       ten->name = id->name + 2;
       ten->directdata = lc;
@@ -151,7 +149,7 @@ void TreeViewViewLayer::add_layer_collections_recursive(ListBase &tree,
     }
 
     add_layer_collections_recursive(ten->subtree, lc->layer_collections, *ten);
-    if (!exclude && _show_objects) {
+    if (!exclude && show_objects_) {
       add_layer_collection_objects(ten->subtree, *lc, *ten);
     }
   }
@@ -162,9 +160,9 @@ void TreeViewViewLayer::add_layer_collection_objects(ListBase &tree,
                                                      TreeElement &ten)
 {
   for (CollectionObject *cob : List<CollectionObject>(lc.collection->gobject)) {
-    Base *base = BKE_view_layer_base_find(_view_layer, cob->ob);
+    Base *base = BKE_view_layer_base_find(view_layer_, cob->ob);
     TreeElement *te_object = outliner_add_element(
-        &_space_outliner, &tree, base->object, &ten, 0, 0);
+        &space_outliner_, &tree, base->object, &ten, 0, 0);
     te_object->directdata = base;
 
     if (!(base->flag & BASE_VISIBLE_VIEWLAYER)) {
@@ -176,7 +174,7 @@ void TreeViewViewLayer::add_layer_collection_objects(ListBase &tree,
 void TreeViewViewLayer::add_layer_collection_objects_children(TreeElement &collection_tree_elem)
 {
   /* Call helper to add children. */
-  ObjectsChildrenBuilder child_builder{_space_outliner};
+  ObjectsChildrenBuilder child_builder{space_outliner_};
   child_builder(collection_tree_elem);
 }
 
@@ -190,7 +188,7 @@ void TreeViewViewLayer::add_layer_collection_objects_children(TreeElement &colle
  *
  * \{ */
 
-ObjectsChildrenBuilder::ObjectsChildrenBuilder(SpaceOutliner &outliner) : _outliner(outliner)
+ObjectsChildrenBuilder::ObjectsChildrenBuilder(SpaceOutliner &outliner) : outliner_(outliner)
 {
 }
 
@@ -216,7 +214,7 @@ void ObjectsChildrenBuilder::object_tree_elements_lookup_create_recursive(TreeEl
     if (tselem->type == 0 && te->idcode == ID_OB) {
       Object *ob = (Object *)tselem->id;
       /* Lookup children or add new, empty children vector. */
-      Vector<TreeElement *> &tree_elements = _object_tree_elements_map.lookup_or_add(ob, {});
+      Vector<TreeElement *> &tree_elements = object_tree_elements_map_.lookup_or_add(ob, {});
 
       tree_elements.append(te);
       object_tree_elements_lookup_create_recursive(te);
@@ -230,7 +228,7 @@ void ObjectsChildrenBuilder::object_tree_elements_lookup_create_recursive(TreeEl
  */
 void ObjectsChildrenBuilder::make_object_parent_hierarchy_collections()
 {
-  for (ObjectTreeElementsMap::MutableItem item : _object_tree_elements_map.items()) {
+  for (ObjectTreeElementsMap::MutableItem item : object_tree_elements_map_.items()) {
     Object *child = item.key;
 
     if (child->parent == nullptr) {
@@ -238,7 +236,7 @@ void ObjectsChildrenBuilder::make_object_parent_hierarchy_collections()
     }
 
     Vector<TreeElement *> &child_ob_tree_elements = item.value;
-    Vector<TreeElement *> *parent_ob_tree_elements = _object_tree_elements_map.lookup_ptr(
+    Vector<TreeElement *> *parent_ob_tree_elements = object_tree_elements_map_.lookup_ptr(
         child->parent);
     if (parent_ob_tree_elements == nullptr) {
       continue;
@@ -272,7 +270,7 @@ void ObjectsChildrenBuilder::make_object_parent_hierarchy_collections()
         /* We add the child in the tree even if it is not in the collection.
          * We deliberately clear its sub-tree though, to make it less prominent. */
         TreeElement *child_ob_tree_element = outliner_add_element(
-            &_outliner, &parent_ob_tree_element->subtree, child, parent_ob_tree_element, 0, 0);
+            &outliner_, &parent_ob_tree_element->subtree, child, parent_ob_tree_element, 0, 0);
         outliner_free_tree(&child_ob_tree_element->subtree);
         child_ob_tree_element->flag |= TE_CHILD_NOT_IN_COLLECTION;
         child_ob_tree_elements.append(child_ob_tree_element);
@@ -283,6 +281,4 @@ void ObjectsChildrenBuilder::make_object_parent_hierarchy_collections()
 
 /** \} */
 
-}  // namespace outliner
-}  // namespace ed
-}  // namespace blender
+}  // namespace blender::ed::outliner