Outliner: Port RNA elements to new tree-element design

Continuation of work started in 2e221de4ceee and 249e4df110e0.

Adds new tree-element classes for RNA structs, properties and array
elements. This isn't exactly a copy and paste, even though logic should
effectively be the same. Further cleanups are included to share code in
a nice way, improve code with simple C++ features, etc.

3 files changed, 334 insertions, 0 deletions

diff --git a/source/blender/editors/space_outliner/tree/tree_element.cc b/source/blender/editors/space_outliner/tree/tree_element.cc
index ea78f70f86d..bed28e59f0b 100644
--- a/source/blender/editors/space_outliner/tree/tree_element.cc
+++ b/source/blender/editors/space_outliner/tree/tree_element.cc
@@ -33,6 +33,7 @@
 #include "tree_element_id.hh"
 #include "tree_element_nla.hh"
 #include "tree_element_overrides.hh"
+#include "tree_element_rna.hh"
 #include "tree_element_scene_objects.hh"
 #include "tree_element_view_layer.hh"
 
@@ -86,6 +87,15 @@ std::unique_ptr<AbstractTreeElement> AbstractTreeElement::createFromType(const i
     case TSE_LIBRARY_OVERRIDE:
       return std::make_unique<TreeElementOverridesProperty>(
           legacy_te, *static_cast<TreeElementOverridesData *>(idv));
+    case TSE_RNA_STRUCT:
+      return std::make_unique<TreeElementRNAStruct>(legacy_te,
+                                                    *reinterpret_cast<PointerRNA *>(idv));
+    case TSE_RNA_PROPERTY:
+      return std::make_unique<TreeElementRNAProperty>(
+          legacy_te, *reinterpret_cast<PointerRNA *>(idv), legacy_te.index);
+    case TSE_RNA_ARRAY_ELEM:
+      return std::make_unique<TreeElementRNAArrayElement>(
+          legacy_te, *reinterpret_cast<PointerRNA *>(idv), legacy_te.index);
     default:
       break;
   }
diff --git a/source/blender/editors/space_outliner/tree/tree_element_rna.cc b/source/blender/editors/space_outliner/tree/tree_element_rna.cc
new file mode 100644
index 00000000000..0152f59268d
--- /dev/null
+++ b/source/blender/editors/space_outliner/tree/tree_element_rna.cc
@@ -0,0 +1,249 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+/** \file
+ * \ingroup spoutliner
+ */
+
+#include <climits>
+#include <iostream>
+
+#include "BLI_listbase.h"
+#include "BLI_string.h"
+
+#include "BLT_translation.h"
+
+#include "DNA_outliner_types.h"
+#include "DNA_space_types.h"
+
+#include "MEM_guardedalloc.h"
+
+#include "RNA_access.h"
+
+#include "../outliner_intern.hh"
+
+#include "tree_element_rna.hh"
+
+namespace blender::ed::outliner {
+
+/* Don't display arrays larger, weak but index is stored as a short,
+ * also the outliner isn't intended for editing such large data-sets. */
+BLI_STATIC_ASSERT(sizeof(TreeElement::index) == 2, "Index is no longer short!")
+
+/* -------------------------------------------------------------------- */
+/* Common functionality (#TreeElementRNACommon Base Class) */
+
+TreeElementRNACommon::TreeElementRNACommon(TreeElement &legacy_te, PointerRNA &rna_ptr)
+    : AbstractTreeElement(legacy_te), rna_ptr_(rna_ptr)
+{
+  /* Create an empty tree-element. */
+  if (!isRNAValid()) {
+    legacy_te_.name = IFACE_("(empty)");
+    return;
+  }
+
+  legacy_te_.rnaptr = rna_ptr;
+}
+
+bool TreeElementRNACommon::isExpandValid() const
+{
+  return true;
+}
+
+bool TreeElementRNACommon::isRNAValid() const
+{
+  return rna_ptr_.data != nullptr;
+}
+
+bool TreeElementRNACommon::expandPoll(const SpaceOutliner &) const
+{
+  return isRNAValid();
+}
+
+/* -------------------------------------------------------------------- */
+/* RNA Struct */
+
+TreeElementRNAStruct::TreeElementRNAStruct(TreeElement &legacy_te, PointerRNA &rna_ptr)
+    : TreeElementRNACommon(legacy_te, rna_ptr)
+{
+  if (!isRNAValid()) {
+    return;
+  }
+
+  legacy_te_.name = RNA_struct_name_get_alloc(&rna_ptr, nullptr, 0, nullptr);
+  if (legacy_te_.name) {
+    legacy_te_.flag |= TE_FREE_NAME;
+  }
+  else {
+    legacy_te_.name = RNA_struct_ui_name(rna_ptr.type);
+  }
+}
+
+void TreeElementRNAStruct::expand(SpaceOutliner &space_outliner) const
+{
+  TreeStoreElem &tselem = *TREESTORE(&legacy_te_);
+  PointerRNA *ptr = &legacy_te_.rnaptr;
+
+  /* If searching don't expand RNA entries */
+  if (SEARCHING_OUTLINER(&space_outliner) && BLI_strcasecmp("RNA", legacy_te_.name) == 0) {
+    tselem.flag &= ~TSE_CHILDSEARCH;
+  }
+
+  PropertyRNA *iterprop = RNA_struct_iterator_property(ptr->type);
+  int tot = RNA_property_collection_length(ptr, iterprop);
+  CLAMP_MAX(tot, max_index);
+
+  /* auto open these cases */
+  if (!legacy_te_.parent ||
+      (RNA_property_type(reinterpret_cast<PropertyRNA *>(legacy_te_.parent->directdata))) ==
+          PROP_POINTER) {
+    if (!tselem.used) {
+      tselem.flag &= ~TSE_CLOSED;
+    }
+  }
+
+  if (TSELEM_OPEN(&tselem, &space_outliner)) {
+    for (int index = 0; index < tot; index++) {
+      PointerRNA propptr;
+      RNA_property_collection_lookup_int(ptr, iterprop, index, &propptr);
+      if (!(RNA_property_flag(reinterpret_cast<PropertyRNA *>(propptr.data)) & PROP_HIDDEN)) {
+        outliner_add_element(&space_outliner,
+                             &legacy_te_.subtree,
+                             (void *)ptr,
+                             &legacy_te_,
+                             TSE_RNA_PROPERTY,
+                             index);
+      }
+    }
+  }
+  else if (tot) {
+    legacy_te_.flag |= TE_LAZY_CLOSED;
+  }
+}
+
+/* -------------------------------------------------------------------- */
+/* RNA Property */
+
+TreeElementRNAProperty::TreeElementRNAProperty(TreeElement &legacy_te,
+                                               PointerRNA &rna_ptr,
+                                               const int index)
+    : TreeElementRNACommon(legacy_te, rna_ptr)
+{
+  if (!isRNAValid()) {
+    return;
+  }
+
+  PointerRNA propptr;
+  PropertyRNA *iterprop = RNA_struct_iterator_property(rna_ptr.type);
+  RNA_property_collection_lookup_int(&rna_ptr, iterprop, index, &propptr);
+
+  PropertyRNA *prop = reinterpret_cast<PropertyRNA *>(propptr.data);
+
+  legacy_te_.name = RNA_property_ui_name(prop);
+  legacy_te_.directdata = prop;
+  rna_prop_ = prop;
+}
+
+void TreeElementRNAProperty::expand(SpaceOutliner &space_outliner) const
+{
+  TreeStoreElem &tselem = *TREESTORE(&legacy_te_);
+  PointerRNA rna_ptr = rna_ptr_;
+  PropertyType proptype = RNA_property_type(rna_prop_);
+
+  /* If searching don't expand RNA entries */
+  if (SEARCHING_OUTLINER(&space_outliner) && BLI_strcasecmp("RNA", legacy_te_.name) == 0) {
+    tselem.flag &= ~TSE_CHILDSEARCH;
+  }
+
+  if (proptype == PROP_POINTER) {
+    PointerRNA pptr = RNA_property_pointer_get(&rna_ptr, rna_prop_);
+
+    if (pptr.data) {
+      if (TSELEM_OPEN(&tselem, &space_outliner)) {
+        outliner_add_element(
+            &space_outliner, &legacy_te_.subtree, (void *)&pptr, &legacy_te_, TSE_RNA_STRUCT, -1);
+      }
+      else {
+        legacy_te_.flag |= TE_LAZY_CLOSED;
+      }
+    }
+  }
+  else if (proptype == PROP_COLLECTION) {
+    int tot = RNA_property_collection_length(&rna_ptr, rna_prop_);
+    CLAMP_MAX(tot, max_index);
+
+    if (TSELEM_OPEN(&tselem, &space_outliner)) {
+      for (int index = 0; index < tot; index++) {
+        PointerRNA pptr;
+        RNA_property_collection_lookup_int(&rna_ptr, rna_prop_, index, &pptr);
+        outliner_add_element(&space_outliner,
+                             &legacy_te_.subtree,
+                             (void *)&pptr,
+                             &legacy_te_,
+                             TSE_RNA_STRUCT,
+                             index);
+      }
+    }
+    else if (tot) {
+      legacy_te_.flag |= TE_LAZY_CLOSED;
+    }
+  }
+  else if (ELEM(proptype, PROP_BOOLEAN, PROP_INT, PROP_FLOAT)) {
+    int tot = RNA_property_array_length(&rna_ptr, rna_prop_);
+    CLAMP_MAX(tot, max_index);
+
+    if (TSELEM_OPEN(&tselem, &space_outliner)) {
+      for (int index = 0; index < tot; index++) {
+        outliner_add_element(&space_outliner,
+                             &legacy_te_.subtree,
+                             &rna_ptr,
+                             &legacy_te_,
+                             TSE_RNA_ARRAY_ELEM,
+                             index);
+      }
+    }
+    else if (tot) {
+      legacy_te_.flag |= TE_LAZY_CLOSED;
+    }
+  }
+}
+
+/* -------------------------------------------------------------------- */
+/* RNA Array Element */
+
+TreeElementRNAArrayElement::TreeElementRNAArrayElement(TreeElement &legacy_te,
+                                                       PointerRNA &rna_ptr,
+                                                       const int index)
+    : TreeElementRNACommon(legacy_te, rna_ptr)
+{
+  PropertyRNA *prop = reinterpret_cast<PropertyRNA *>(legacy_te_.parent->directdata);
+  legacy_te_.directdata = prop;
+  legacy_te_.index = index;
+
+  char c = RNA_property_array_item_char(prop, index);
+
+  legacy_te_.name = reinterpret_cast<char *>(
+      MEM_callocN(sizeof(char[20]), "OutlinerRNAArrayName"));
+  if (c) {
+    sprintf((char *)legacy_te_.name, "  %c", c);
+  }
+  else {
+    sprintf((char *)legacy_te_.name, "  %d", index + 1);
+  }
+  legacy_te_.flag |= TE_FREE_NAME;
+}
+
+}  // namespace blender::ed::outliner
diff --git a/source/blender/editors/space_outliner/tree/tree_element_rna.hh b/source/blender/editors/space_outliner/tree/tree_element_rna.hh
new file mode 100644
index 00000000000..352b8763acb
--- /dev/null
+++ b/source/blender/editors/space_outliner/tree/tree_element_rna.hh
@@ -0,0 +1,75 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+/** \file
+ * \ingroup spoutliner
+ */
+
+#pragma once
+
+#include <limits>
+
+#include "RNA_types.h"
+
+#include "tree_element.hh"
+
+struct PointerRNA;
+
+namespace blender::ed::outliner {
+
+/**
+ * Base class for common behavior of RNA tree elements.
+ */
+class TreeElementRNACommon : public AbstractTreeElement {
+ protected:
+  constexpr static int max_index = std::numeric_limits<short>::max();
+  PointerRNA rna_ptr_;
+
+ public:
+  TreeElementRNACommon(TreeElement &legacy_te, PointerRNA &rna_ptr);
+  bool isExpandValid() const override;
+  bool expandPoll(const SpaceOutliner &) const override;
+
+  bool isRNAValid() const;
+};
+
+/* -------------------------------------------------------------------- */
+
+class TreeElementRNAStruct : public TreeElementRNACommon {
+ public:
+  TreeElementRNAStruct(TreeElement &legacy_te, PointerRNA &rna_ptr);
+  void expand(SpaceOutliner &space_outliner) const override;
+};
+
+/* -------------------------------------------------------------------- */
+
+class TreeElementRNAProperty : public TreeElementRNACommon {
+ private:
+  PropertyRNA *rna_prop_ = nullptr;
+
+ public:
+  TreeElementRNAProperty(TreeElement &legacy_te, PointerRNA &rna_ptr, int index);
+  void expand(SpaceOutliner &space_outliner) const override;
+};
+
+/* -------------------------------------------------------------------- */
+
+class TreeElementRNAArrayElement : public TreeElementRNACommon {
+ public:
+  TreeElementRNAArrayElement(TreeElement &legacy_te, PointerRNA &rna_ptr, int index);
+};
+
+}  // namespace blender::ed::outliner