Outliner: Compile all Outliner files in C++

We want to refactor quite some of the Outliner code using C++, this is a
logical step to help the transition to a new architecture.

Includes plenty of fixes to make this compile without warnings, trying
not to change logic. The usual stuff (casts from `void *`, designated
initializers, compound literals, etc.).

1 files changed, 1975 insertions, 0 deletions

diff --git a/source/blender/editors/space_outliner/outliner_tree.cc b/source/blender/editors/space_outliner/outliner_tree.cc
new file mode 100644
index 00000000000..de0f7a0f9df
--- /dev/null
+++ b/source/blender/editors/space_outliner/outliner_tree.cc
@@ -0,0 +1,1975 @@
+/*
+ * 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.
+ *
+ * The Original Code is Copyright (C) 2004 Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup spoutliner
+ */
+
+#include <math.h>
+#include <string.h>
+
+#include "MEM_guardedalloc.h"
+
+#include "DNA_anim_types.h"
+#include "DNA_armature_types.h"
+#include "DNA_cachefile_types.h"
+#include "DNA_camera_types.h"
+#include "DNA_collection_types.h"
+#include "DNA_constraint_types.h"
+#include "DNA_gpencil_modifier_types.h"
+#include "DNA_gpencil_types.h"
+#include "DNA_hair_types.h"
+#include "DNA_key_types.h"
+#include "DNA_light_types.h"
+#include "DNA_lightprobe_types.h"
+#include "DNA_linestyle_types.h"
+#include "DNA_material_types.h"
+#include "DNA_mesh_types.h"
+#include "DNA_meta_types.h"
+#include "DNA_object_types.h"
+#include "DNA_particle_types.h"
+#include "DNA_pointcloud_types.h"
+#include "DNA_scene_types.h"
+#include "DNA_sequence_types.h"
+#include "DNA_shader_fx_types.h"
+#include "DNA_simulation_types.h"
+#include "DNA_speaker_types.h"
+#include "DNA_volume_types.h"
+#include "DNA_world_types.h"
+
+#include "BLI_blenlib.h"
+#include "BLI_fnmatch.h"
+#include "BLI_listbase.h"
+#include "BLI_mempool.h"
+#include "BLI_utildefines.h"
+
+#include "BLT_translation.h"
+
+#include "BKE_armature.h"
+#include "BKE_deform.h"
+#include "BKE_layer.h"
+#include "BKE_lib_id.h"
+#include "BKE_main.h"
+#include "BKE_modifier.h"
+#include "BKE_outliner_treehash.h"
+
+#include "ED_screen.h"
+
+#include "RNA_access.h"
+
+#include "UI_interface.h"
+#include "UI_resources.h"
+
+#include "outliner_intern.hh"
+#include "tree/tree_display.h"
+#include "tree/tree_element.h"
+
+#ifdef WIN32
+#  include "BLI_math_base.h" /* M_PI */
+#endif
+
+/* prototypes */
+static int outliner_exclude_filter_get(const SpaceOutliner *space_outliner);
+
+/* ********************************************************* */
+/* Persistent Data */
+
+static void outliner_storage_cleanup(SpaceOutliner *space_outliner)
+{
+  BLI_mempool *ts = space_outliner->treestore;
+
+  if (ts) {
+    TreeStoreElem *tselem;
+    int unused = 0;
+
+    /* each element used once, for ID blocks with more users to have each a treestore */
+    BLI_mempool_iter iter;
+
+    BLI_mempool_iternew(ts, &iter);
+    while ((tselem = reinterpret_cast<TreeStoreElem *>(BLI_mempool_iterstep(&iter)))) {
+      tselem->used = 0;
+    }
+
+    /* cleanup only after reading file or undo step, and always for
+     * RNA data-blocks view in order to save memory */
+    if (space_outliner->storeflag & SO_TREESTORE_CLEANUP) {
+      space_outliner->storeflag &= ~SO_TREESTORE_CLEANUP;
+
+      BLI_mempool_iternew(ts, &iter);
+      while ((tselem = reinterpret_cast<TreeStoreElem *>(BLI_mempool_iterstep(&iter)))) {
+        if (tselem->id == NULL) {
+          unused++;
+        }
+      }
+
+      if (unused) {
+        if (BLI_mempool_len(ts) == unused) {
+          BLI_mempool_destroy(ts);
+          space_outliner->treestore = NULL;
+          if (space_outliner->runtime->treehash) {
+            BKE_outliner_treehash_free(space_outliner->runtime->treehash);
+            space_outliner->runtime->treehash = NULL;
+          }
+        }
+        else {
+          TreeStoreElem *tsenew;
+          BLI_mempool *new_ts = BLI_mempool_create(
+              sizeof(TreeStoreElem), BLI_mempool_len(ts) - unused, 512, BLI_MEMPOOL_ALLOW_ITER);
+          BLI_mempool_iternew(ts, &iter);
+          while ((tselem = reinterpret_cast<TreeStoreElem *>(BLI_mempool_iterstep(&iter)))) {
+            if (tselem->id) {
+              tsenew = reinterpret_cast<TreeStoreElem *>(BLI_mempool_alloc(new_ts));
+              *tsenew = *tselem;
+            }
+          }
+          BLI_mempool_destroy(ts);
+          space_outliner->treestore = new_ts;
+          if (space_outliner->runtime->treehash) {
+            /* update hash table to fix broken pointers */
+            BKE_outliner_treehash_rebuild_from_treestore(space_outliner->runtime->treehash,
+                                                         space_outliner->treestore);
+          }
+        }
+      }
+    }
+    else if (space_outliner->runtime->treehash) {
+      BKE_outliner_treehash_clear_used(space_outliner->runtime->treehash);
+    }
+  }
+}
+
+static void check_persistent(
+    SpaceOutliner *space_outliner, TreeElement *te, ID *id, short type, short nr)
+{
+  if (space_outliner->treestore == NULL) {
+    /* if treestore was not created in readfile.c, create it here */
+    space_outliner->treestore = BLI_mempool_create(
+        sizeof(TreeStoreElem), 1, 512, BLI_MEMPOOL_ALLOW_ITER);
+  }
+  if (space_outliner->runtime->treehash == NULL) {
+    space_outliner->runtime->treehash = reinterpret_cast<GHash *>(
+        BKE_outliner_treehash_create_from_treestore(space_outliner->treestore));
+  }
+
+  /* find any unused tree element in treestore and mark it as used
+   * (note that there may be multiple unused elements in case of linked objects) */
+  TreeStoreElem *tselem = BKE_outliner_treehash_lookup_unused(
+      space_outliner->runtime->treehash, type, nr, id);
+  if (tselem) {
+    te->store_elem = tselem;
+    tselem->used = 1;
+    return;
+  }
+
+  /* add 1 element to treestore */
+  tselem = reinterpret_cast<TreeStoreElem *>(BLI_mempool_alloc(space_outliner->treestore));
+  tselem->type = type;
+  tselem->nr = type ? nr : 0;
+  tselem->id = id;
+  tselem->used = 0;
+  tselem->flag = TSE_CLOSED;
+  te->store_elem = tselem;
+  BKE_outliner_treehash_add_element(space_outliner->runtime->treehash, tselem);
+}
+
+/* ********************************************************* */
+/* Tree Management */
+
+void outliner_free_tree(ListBase *tree)
+{
+  LISTBASE_FOREACH_MUTABLE (TreeElement *, element, tree) {
+    outliner_free_tree_element(element, tree);
+  }
+}
+
+void outliner_cleanup_tree(SpaceOutliner *space_outliner)
+{
+  outliner_free_tree(&space_outliner->tree);
+  outliner_storage_cleanup(space_outliner);
+}
+
+void outliner_free_tree_element(TreeElement *element, ListBase *parent_subtree)
+{
+  BLI_assert(BLI_findindex(parent_subtree, element) > -1);
+  BLI_remlink(parent_subtree, element);
+
+  outliner_free_tree(&element->subtree);
+
+  if (element->flag & TE_FREE_NAME) {
+    MEM_freeN((void *)element->name);
+  }
+  outliner_tree_element_type_free(&element->type);
+  MEM_freeN(element);
+}
+
+/* ********************************************************* */
+
+/* -------------------------------------------------------- */
+
+bool outliner_requires_rebuild_on_select_or_active_change(const SpaceOutliner *space_outliner)
+{
+  int exclude_flags = outliner_exclude_filter_get(space_outliner);
+  /* Need to rebuild tree to re-apply filter if select/active changed while filtering based on
+   * select/active. */
+  return exclude_flags & (SO_FILTER_OB_STATE_SELECTED | SO_FILTER_OB_STATE_ACTIVE);
+}
+
+bool outliner_requires_rebuild_on_open_change(const SpaceOutliner *space_outliner)
+{
+  return ELEM(space_outliner->outlinevis, SO_DATA_API);
+}
+
+/* special handling of hierarchical non-lib data */
+static void outliner_add_bone(SpaceOutliner *space_outliner,
+                              ListBase *lb,
+                              ID *id,
+                              Bone *curBone,
+                              TreeElement *parent,
+                              int *a)
+{
+  TreeElement *te = outliner_add_element(space_outliner, lb, id, parent, TSE_BONE, *a);
+
+  (*a)++;
+  te->name = curBone->name;
+  te->directdata = curBone;
+
+  LISTBASE_FOREACH (Bone *, child_bone, &curBone->childbase) {
+    outliner_add_bone(space_outliner, &te->subtree, id, child_bone, te, a);
+  }
+}
+
+bool outliner_animdata_test(const AnimData *adt)
+{
+  if (adt) {
+    return (adt->action || adt->drivers.first || adt->nla_tracks.first);
+  }
+  return false;
+}
+
+#ifdef WITH_FREESTYLE
+static void outliner_add_line_styles(SpaceOutliner *space_outliner,
+                                     ListBase *lb,
+                                     Scene *sce,
+                                     TreeElement *te)
+{
+  ViewLayer *view_layer;
+  FreestyleLineSet *lineset;
+
+  for (view_layer = sce->view_layers.first; view_layer; view_layer = view_layer->next) {
+    for (lineset = view_layer->freestyle_config.linesets.first; lineset; lineset = lineset->next) {
+      FreestyleLineStyle *linestyle = lineset->linestyle;
+      if (linestyle) {
+        linestyle->id.tag |= LIB_TAG_DOIT;
+      }
+    }
+  }
+  for (view_layer = sce->view_layers.first; view_layer; view_layer = view_layer->next) {
+    for (lineset = view_layer->freestyle_config.linesets.first; lineset; lineset = lineset->next) {
+      FreestyleLineStyle *linestyle = lineset->linestyle;
+      if (linestyle) {
+        if (!(linestyle->id.tag & LIB_TAG_DOIT)) {
+          continue;
+        }
+        linestyle->id.tag &= ~LIB_TAG_DOIT;
+        outliner_add_element(space_outliner, lb, linestyle, te, TSE_SOME_ID, 0);
+      }
+    }
+  }
+}
+#endif
+
+/* Can be inlined if necessary. */
+static void outliner_add_object_contents(SpaceOutliner *space_outliner,
+                                         TreeElement *te,
+                                         TreeStoreElem *tselem,
+                                         Object *ob)
+{
+  if (outliner_animdata_test(ob->adt)) {
+    outliner_add_element(space_outliner, &te->subtree, ob, te, TSE_ANIM_DATA, 0);
+  }
+
+  /* FIXME: add a special type for this. */
+  outliner_add_element(space_outliner, &te->subtree, ob->poselib, te, TSE_SOME_ID, 0);
+
+  if (ob->proxy && !ID_IS_LINKED(ob)) {
+    outliner_add_element(space_outliner, &te->subtree, ob->proxy, te, TSE_PROXY, 0);
+  }
+
+  outliner_add_element(space_outliner, &te->subtree, ob->data, te, TSE_SOME_ID, 0);
+
+  if (ob->pose) {
+    bArmature *arm = reinterpret_cast<bArmature *>(ob->data);
+    TreeElement *tenla = outliner_add_element(
+        space_outliner, &te->subtree, ob, te, TSE_POSE_BASE, 0);
+    tenla->name = IFACE_("Pose");
+
+    /* channels undefined in editmode, but we want the 'tenla' pose icon itself */
+    if ((arm->edbo == NULL) && (ob->mode & OB_MODE_POSE)) {
+      int const_index = 1000; /* ensure unique id for bone constraints */
+      int a;
+      LISTBASE_FOREACH_INDEX (bPoseChannel *, pchan, &ob->pose->chanbase, a) {
+        TreeElement *ten = outliner_add_element(
+            space_outliner, &tenla->subtree, ob, tenla, TSE_POSE_CHANNEL, a);
+        ten->name = pchan->name;
+        ten->directdata = pchan;
+        pchan->temp = (void *)ten;
+
+        if (!BLI_listbase_is_empty(&pchan->constraints)) {
+          /* Object *target; */
+          TreeElement *tenla1 = outliner_add_element(
+              space_outliner, &ten->subtree, ob, ten, TSE_CONSTRAINT_BASE, 0);
+          tenla1->name = IFACE_("Constraints");
+          /* char *str; */
+
+          LISTBASE_FOREACH (bConstraint *, con, &pchan->constraints) {
+            TreeElement *ten1 = outliner_add_element(
+                space_outliner, &tenla1->subtree, ob, tenla1, TSE_CONSTRAINT, const_index);
+#if 0 /* disabled as it needs to be reworked for recoded constraints system */
+            target = get_constraint_target(con, &str);
+            if (str && str[0]) {
+              ten1->name = str;
+            }
+            else if (target) {
+              ten1->name = target->id.name + 2;
+            }
+            else {
+              ten1->name = con->name;
+            }
+#endif
+            ten1->name = con->name;
+            ten1->directdata = con;
+            /* possible add all other types links? */
+          }
+          const_index++;
+        }
+      }
+      /* make hierarchy */
+      TreeElement *ten = reinterpret_cast<TreeElement *>(tenla->subtree.first);
+      while (ten) {
+        TreeElement *nten = ten->next, *par;
+        tselem = TREESTORE(ten);
+        if (tselem->type == TSE_POSE_CHANNEL) {
+          bPoseChannel *pchan = (bPoseChannel *)ten->directdata;
+          if (pchan->parent) {
+            BLI_remlink(&tenla->subtree, ten);
+            par = (TreeElement *)pchan->parent->temp;
+            BLI_addtail(&par->subtree, ten);
+            ten->parent = par;
+          }
+        }
+        ten = nten;
+      }
+    }
+
+    /* Pose Groups */
+    if (!BLI_listbase_is_empty(&ob->pose->agroups)) {
+      TreeElement *ten_bonegrp = outliner_add_element(
+          space_outliner, &te->subtree, ob, te, TSE_POSEGRP_BASE, 0);
+      ten_bonegrp->name = IFACE_("Bone Groups");
+
+      int index;
+      LISTBASE_FOREACH_INDEX (bActionGroup *, agrp, &ob->pose->agroups, index) {
+        TreeElement *ten = outliner_add_element(
+            space_outliner, &ten_bonegrp->subtree, ob, ten_bonegrp, TSE_POSEGRP, index);
+        ten->name = agrp->name;
+        ten->directdata = agrp;
+      }
+    }
+  }
+
+  for (int a = 0; a < ob->totcol; a++) {
+    outliner_add_element(space_outliner, &te->subtree, ob->mat[a], te, TSE_SOME_ID, a);
+  }
+
+  if (!BLI_listbase_is_empty(&ob->constraints)) {
+    TreeElement *tenla = outliner_add_element(
+        space_outliner, &te->subtree, ob, te, TSE_CONSTRAINT_BASE, 0);
+    tenla->name = IFACE_("Constraints");
+
+    int index;
+    LISTBASE_FOREACH_INDEX (bConstraint *, con, &ob->constraints, index) {
+      TreeElement *ten = outliner_add_element(
+          space_outliner, &tenla->subtree, ob, tenla, TSE_CONSTRAINT, index);
+#if 0 /* disabled due to constraints system targets recode... code here needs review */
+      target = get_constraint_target(con, &str);
+      if (str && str[0]) {
+        ten->name = str;
+      }
+      else if (target) {
+        ten->name = target->id.name + 2;
+      }
+      else {
+        ten->name = con->name;
+      }
+#endif
+      ten->name = con->name;
+      ten->directdata = con;
+      /* possible add all other types links? */
+    }
+  }
+
+  if (!BLI_listbase_is_empty(&ob->modifiers)) {
+    TreeElement *ten_mod = outliner_add_element(
+        space_outliner, &te->subtree, ob, te, TSE_MODIFIER_BASE, 0);
+    ten_mod->name = IFACE_("Modifiers");
+
+    int index;
+    LISTBASE_FOREACH_INDEX (ModifierData *, md, &ob->modifiers, index) {
+      TreeElement *ten = outliner_add_element(
+          space_outliner, &ten_mod->subtree, ob, ten_mod, TSE_MODIFIER, index);
+      ten->name = md->name;
+      ten->directdata = md;
+
+      if (md->type == eModifierType_Lattice) {
+        outliner_add_element(space_outliner,
+                             &ten->subtree,
+                             ((LatticeModifierData *)md)->object,
+                             ten,
+                             TSE_LINKED_OB,
+                             0);
+      }
+      else if (md->type == eModifierType_Curve) {
+        outliner_add_element(space_outliner,
+                             &ten->subtree,
+                             ((CurveModifierData *)md)->object,
+                             ten,
+                             TSE_LINKED_OB,
+                             0);
+      }
+      else if (md->type == eModifierType_Armature) {
+        outliner_add_element(space_outliner,
+                             &ten->subtree,
+                             ((ArmatureModifierData *)md)->object,
+                             ten,
+                             TSE_LINKED_OB,
+                             0);
+      }
+      else if (md->type == eModifierType_Hook) {
+        outliner_add_element(space_outliner,
+                             &ten->subtree,
+                             ((HookModifierData *)md)->object,
+                             ten,
+                             TSE_LINKED_OB,
+                             0);
+      }
+      else if (md->type == eModifierType_ParticleSystem) {
+        ParticleSystem *psys = ((ParticleSystemModifierData *)md)->psys;
+        TreeElement *ten_psys;
+
+        ten_psys = outliner_add_element(space_outliner, &ten->subtree, ob, te, TSE_LINKED_PSYS, 0);
+        ten_psys->directdata = psys;
+        ten_psys->name = psys->part->id.name + 2;
+      }
+    }
+  }
+
+  /* Grease Pencil modifiers. */
+  if (!BLI_listbase_is_empty(&ob->greasepencil_modifiers)) {
+    TreeElement *ten_mod = outliner_add_element(
+        space_outliner, &te->subtree, ob, te, TSE_MODIFIER_BASE, 0);
+    ten_mod->name = IFACE_("Modifiers");
+
+    int index;
+    LISTBASE_FOREACH_INDEX (GpencilModifierData *, md, &ob->greasepencil_modifiers, index) {
+      TreeElement *ten = outliner_add_element(
+          space_outliner, &ten_mod->subtree, ob, ten_mod, TSE_MODIFIER, index);
+      ten->name = md->name;
+      ten->directdata = md;
+
+      if (md->type == eGpencilModifierType_Armature) {
+        outliner_add_element(space_outliner,
+                             &ten->subtree,
+                             ((ArmatureGpencilModifierData *)md)->object,
+                             ten,
+                             TSE_LINKED_OB,
+                             0);
+      }
+      else if (md->type == eGpencilModifierType_Hook) {
+        outliner_add_element(space_outliner,
+                             &ten->subtree,
+                             ((HookGpencilModifierData *)md)->object,
+                             ten,
+                             TSE_LINKED_OB,
+                             0);
+      }
+      else if (md->type == eGpencilModifierType_Lattice) {
+        outliner_add_element(space_outliner,
+                             &ten->subtree,
+                             ((LatticeGpencilModifierData *)md)->object,
+                             ten,
+                             TSE_LINKED_OB,
+                             0);
+      }
+    }
+  }
+
+  /* Grease Pencil effects. */
+  if (!BLI_listbase_is_empty(&ob->shader_fx)) {
+    TreeElement *ten_fx = outliner_add_element(
+        space_outliner, &te->subtree, ob, te, TSE_GPENCIL_EFFECT_BASE, 0);
+    ten_fx->name = IFACE_("Effects");
+
+    int index;
+    LISTBASE_FOREACH_INDEX (ShaderFxData *, fx, &ob->shader_fx, index) {
+      TreeElement *ten = outliner_add_element(
+          space_outliner, &ten_fx->subtree, ob, ten_fx, TSE_GPENCIL_EFFECT, index);
+      ten->name = fx->name;
+      ten->directdata = fx;
+
+      if (fx->type == eShaderFxType_Swirl) {
+        outliner_add_element(space_outliner,
+                             &ten->subtree,
+                             ((SwirlShaderFxData *)fx)->object,
+                             ten,
+                             TSE_LINKED_OB,
+                             0);
+      }
+    }
+  }
+
+  /* vertex groups */
+  if (ELEM(ob->type, OB_MESH, OB_GPENCIL, OB_LATTICE)) {
+    const ListBase *defbase = BKE_object_defgroup_list(ob);
+    if (!BLI_listbase_is_empty(defbase)) {
+      TreeElement *tenla = outliner_add_element(
+          space_outliner, &te->subtree, ob, te, TSE_DEFGROUP_BASE, 0);
+      tenla->name = IFACE_("Vertex Groups");
+
+      int index;
+      LISTBASE_FOREACH_INDEX (bDeformGroup *, defgroup, defbase, index) {
+        TreeElement *ten = outliner_add_element(
+            space_outliner, &tenla->subtree, ob, tenla, TSE_DEFGROUP, index);
+        ten->name = defgroup->name;
+        ten->directdata = defgroup;
+      }
+    }
+  }
+
+  /* duplicated group */
+  if (ob->instance_collection && (ob->transflag & OB_DUPLICOLLECTION)) {
+    outliner_add_element(
+        space_outliner, &te->subtree, ob->instance_collection, te, TSE_SOME_ID, 0);
+  }
+}
+
+/* Can be inlined if necessary. */
+static void outliner_add_id_contents(SpaceOutliner *space_outliner,
+                                     TreeElement *te,
+                                     TreeStoreElem *tselem,
+                                     ID *id)
+{
+  /* tuck pointer back in object, to construct hierarchy */
+  if (GS(id->name) == ID_OB) {
+    id->newid = (ID *)te;
+  }
+
+  /* expand specific data always */
+  switch (GS(id->name)) {
+    case ID_LI:
+    case ID_SCE:
+      BLI_assert_msg(0, "ID type expected to be expanded through new tree-element design");
+      break;
+    case ID_OB: {
+      outliner_add_object_contents(space_outliner, te, tselem, (Object *)id);
+      break;
+    }
+    case ID_ME: {
+      Mesh *me = (Mesh *)id;
+
+      if (outliner_animdata_test(me->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, me, te, TSE_ANIM_DATA, 0);
+      }
+
+      outliner_add_element(space_outliner, &te->subtree, me->key, te, TSE_SOME_ID, 0);
+      for (int a = 0; a < me->totcol; a++) {
+        outliner_add_element(space_outliner, &te->subtree, me->mat[a], te, TSE_SOME_ID, a);
+      }
+      /* could do tfaces with image links, but the images are not grouped nicely.
+       * would require going over all tfaces, sort images in use. etc... */
+      break;
+    }
+    case ID_CU: {
+      Curve *cu = (Curve *)id;
+
+      if (outliner_animdata_test(cu->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, cu, te, TSE_ANIM_DATA, 0);
+      }
+
+      for (int a = 0; a < cu->totcol; a++) {
+        outliner_add_element(space_outliner, &te->subtree, cu->mat[a], te, TSE_SOME_ID, a);
+      }
+      break;
+    }
+    case ID_MB: {
+      MetaBall *mb = (MetaBall *)id;
+
+      if (outliner_animdata_test(mb->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, mb, te, TSE_ANIM_DATA, 0);
+      }
+
+      for (int a = 0; a < mb->totcol; a++) {
+        outliner_add_element(space_outliner, &te->subtree, mb->mat[a], te, TSE_SOME_ID, a);
+      }
+      break;
+    }
+    case ID_MA: {
+      Material *ma = (Material *)id;
+      if (outliner_animdata_test(ma->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, ma, te, TSE_ANIM_DATA, 0);
+      }
+      break;
+    }
+    case ID_TE: {
+      Tex *tex = (Tex *)id;
+      if (outliner_animdata_test(tex->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, tex, te, TSE_ANIM_DATA, 0);
+      }
+      outliner_add_element(space_outliner, &te->subtree, tex->ima, te, TSE_SOME_ID, 0);
+      break;
+    }
+    case ID_CA: {
+      Camera *ca = (Camera *)id;
+      if (outliner_animdata_test(ca->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, ca, te, TSE_ANIM_DATA, 0);
+      }
+      break;
+    }
+    case ID_CF: {
+      CacheFile *cache_file = (CacheFile *)id;
+      if (outliner_animdata_test(cache_file->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, cache_file, te, TSE_ANIM_DATA, 0);
+      }
+
+      break;
+    }
+    case ID_LA: {
+      Light *la = (Light *)id;
+      if (outliner_animdata_test(la->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, la, te, TSE_ANIM_DATA, 0);
+      }
+      break;
+    }
+    case ID_SPK: {
+      Speaker *spk = (Speaker *)id;
+      if (outliner_animdata_test(spk->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, spk, te, TSE_ANIM_DATA, 0);
+      }
+      break;
+    }
+    case ID_LP: {
+      LightProbe *prb = (LightProbe *)id;
+      if (outliner_animdata_test(prb->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, prb, te, TSE_ANIM_DATA, 0);
+      }
+      break;
+    }
+    case ID_WO: {
+      World *wrld = (World *)id;
+      if (outliner_animdata_test(wrld->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, wrld, te, TSE_ANIM_DATA, 0);
+      }
+      break;
+    }
+    case ID_KE: {
+      Key *key = (Key *)id;
+      if (outliner_animdata_test(key->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, key, te, TSE_ANIM_DATA, 0);
+      }
+      break;
+    }
+    case ID_AC: {
+      /* XXX do we want to be exposing the F-Curves here? */
+      /* bAction *act = (bAction *)id; */
+      break;
+    }
+    case ID_AR: {
+      bArmature *arm = (bArmature *)id;
+
+      if (outliner_animdata_test(arm->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, arm, te, TSE_ANIM_DATA, 0);
+      }
+
+      if (arm->edbo) {
+        int a = 0;
+        LISTBASE_FOREACH_INDEX (EditBone *, ebone, arm->edbo, a) {
+          TreeElement *ten = outliner_add_element(
+              space_outliner, &te->subtree, id, te, TSE_EBONE, a);
+          ten->directdata = ebone;
+          ten->name = ebone->name;
+          ebone->temp.p = ten;
+        }
+        /* make hierarchy */
+        TreeElement *ten = arm->edbo->first ? reinterpret_cast<TreeElement *>(
+                                                  ((EditBone *)arm->edbo->first)->temp.p) :
+                                              NULL;
+        while (ten) {
+          TreeElement *nten = ten->next, *par;
+          EditBone *ebone = (EditBone *)ten->directdata;
+          if (ebone->parent) {
+            BLI_remlink(&te->subtree, ten);
+            par = reinterpret_cast<TreeElement *>(ebone->parent->temp.p);
+            BLI_addtail(&par->subtree, ten);
+            ten->parent = par;
+          }
+          ten = nten;
+        }
+      }
+      else {
+        /* do not extend Armature when we have posemode */
+        tselem = TREESTORE(te->parent);
+        if (GS(tselem->id->name) == ID_OB && ((Object *)tselem->id)->mode & OB_MODE_POSE) {
+          /* pass */
+        }
+        else {
+          int a = 0;
+          LISTBASE_FOREACH (Bone *, bone, &arm->bonebase) {
+            outliner_add_bone(space_outliner, &te->subtree, id, bone, te, &a);
+          }
+        }
+      }
+      break;
+    }
+    case ID_LS: {
+      FreestyleLineStyle *linestyle = (FreestyleLineStyle *)id;
+
+      if (outliner_animdata_test(linestyle->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, linestyle, te, TSE_ANIM_DATA, 0);
+      }
+
+      for (int a = 0; a < MAX_MTEX; a++) {
+        if (linestyle->mtex[a]) {
+          outliner_add_element(space_outliner, &te->subtree, linestyle->mtex[a]->tex, te, 0, a);
+        }
+      }
+      break;
+    }
+    case ID_GD: {
+      bGPdata *gpd = (bGPdata *)id;
+
+      if (outliner_animdata_test(gpd->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, gpd, te, TSE_ANIM_DATA, 0);
+      }
+
+      /* TODO: base element for layers? */
+      int index = 0;
+      LISTBASE_FOREACH_BACKWARD (bGPDlayer *, gpl, &gpd->layers) {
+        outliner_add_element(space_outliner, &te->subtree, gpl, te, TSE_GP_LAYER, index);
+        index++;
+      }
+      break;
+    }
+    case ID_GR: {
+      /* Don't expand for instances, creates too many elements. */
+      if (!(te->parent && te->parent->idcode == ID_OB)) {
+        Collection *collection = (Collection *)id;
+        outliner_add_collection_recursive(space_outliner, collection, te);
+      }
+      break;
+    }
+    case ID_HA: {
+      Hair *hair = (Hair *)id;
+      if (outliner_animdata_test(hair->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, hair, te, TSE_ANIM_DATA, 0);
+      }
+      break;
+    }
+    case ID_PT: {
+      PointCloud *pointcloud = (PointCloud *)id;
+      if (outliner_animdata_test(pointcloud->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, pointcloud, te, TSE_ANIM_DATA, 0);
+      }
+      break;
+    }
+    case ID_VO: {
+      Volume *volume = (Volume *)id;
+      if (outliner_animdata_test(volume->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, volume, te, TSE_ANIM_DATA, 0);
+      }
+      break;
+    }
+    case ID_SIM: {
+      Simulation *simulation = (Simulation *)id;
+      if (outliner_animdata_test(simulation->adt)) {
+        outliner_add_element(space_outliner, &te->subtree, simulation, te, TSE_ANIM_DATA, 0);
+      }
+      break;
+    }
+    default:
+      break;
+  }
+}
+
+bool outliner_element_warnings_get(TreeElement *te, int *r_icon, const char **r_message)
+{
+  TreeStoreElem *tselem = TREESTORE(te);
+
+  if (tselem->type != TSE_SOME_ID) {
+    return false;
+  }
+  if (te->idcode != ID_LI) {
+    return false;
+  }
+
+  Library *library = (Library *)tselem->id;
+  if (library->tag & LIBRARY_TAG_RESYNC_REQUIRED) {
+    if (r_icon) {
+      *r_icon = ICON_ERROR;
+    }
+    if (r_message) {
+      *r_message = TIP_(
+          "Contains linked library overrides that need to be resynced, updating the library is "
+          "recommended");
+    }
+    return true;
+  }
+  if (library->id.tag & LIB_TAG_MISSING) {
+    if (r_icon) {
+      *r_icon = ICON_ERROR;
+    }
+    if (r_message) {
+      *r_message = TIP_("Missing library");
+    }
+    return true;
+  }
+  return false;
+}
+
+TreeElement *outliner_add_element(SpaceOutliner *space_outliner,
+                                  ListBase *lb,
+                                  void *idv,
+                                  TreeElement *parent,
+                                  short type,
+                                  short index)
+{
+  ID *id = reinterpret_cast<ID *>(idv);
+
+  if (ELEM(type, TSE_RNA_STRUCT, TSE_RNA_PROPERTY, TSE_RNA_ARRAY_ELEM)) {
+    id = ((PointerRNA *)idv)->owner_id;
+    if (!id) {
+      id = reinterpret_cast<ID *>(((PointerRNA *)idv)->data);
+    }
+  }
+  else if (type == TSE_GP_LAYER) {
+    /* idv is the layer its self */
+    id = TREESTORE(parent)->id;
+  }
+
+  /* exceptions */
+  if (type == TSE_ID_BASE) {
+    /* pass */
+  }
+  else if (id == NULL) {
+    return NULL;
+  }
+
+  if (type == 0) {
+    /* Zero type means real ID, ensure we do not get non-outliner ID types here... */
+    BLI_assert(TREESTORE_ID_TYPE(id));
+  }
+
+  TreeElement *te = MEM_cnew<TreeElement>(__func__);
+  /* add to the visual tree */
+  BLI_addtail(lb, te);
+  /* add to the storage */
+  check_persistent(space_outliner, te, id, type, index);
+  TreeStoreElem *tselem = TREESTORE(te);
+
+  /* if we are searching for something expand to see child elements */
+  if (SEARCHING_OUTLINER(space_outliner)) {
+    tselem->flag |= TSE_CHILDSEARCH;
+  }
+
+  te->parent = parent;
+  te->index = index; /* For data arrays. */
+
+  /* New C++ based type handle (`TreeElementType` in C, `AbstractTreeElement` in C++). Only some
+   * support this, eventually this should replace `TreeElement` entirely. */
+  te->type = outliner_tree_element_type_create(type, te, idv);
+  if (te->type) {
+    /* Element types ported to the new design are expected to have their name set at this point! */
+    BLI_assert(te->name != NULL);
+  }
+
+  if (ELEM(type, TSE_SEQUENCE, TSE_SEQ_STRIP, TSE_SEQUENCE_DUP)) {
+    /* pass */
+  }
+  else if (ELEM(type, TSE_RNA_STRUCT, TSE_RNA_PROPERTY, TSE_RNA_ARRAY_ELEM)) {
+    /* pass */
+  }
+  else if (ELEM(type, TSE_ANIM_DATA, TSE_NLA, TSE_NLA_TRACK, TSE_DRIVER_BASE)) {
+    /* pass */
+  }
+  else if (type == TSE_GP_LAYER) {
+    /* pass */
+  }
+  else if (ELEM(type, TSE_LAYER_COLLECTION, TSE_SCENE_COLLECTION_BASE, TSE_VIEW_COLLECTION_BASE)) {
+    /* pass */
+  }
+  else if (type == TSE_ID_BASE) {
+    /* pass */
+  }
+  else if (type == TSE_SOME_ID) {
+    if (!te->type) {
+      BLI_assert_msg(0, "Expected this ID type to be ported to new Outliner tree-element design");
+    }
+  }
+  else if (ELEM(type, TSE_LIBRARY_OVERRIDE_BASE, TSE_LIBRARY_OVERRIDE)) {
+    if (!te->type) {
+      BLI_assert_msg(0,
+                     "Expected override types to be ported to new Outliner tree-element design");
+    }
+  }
+  else {
+    /* Other cases must be caught above. */
+    BLI_assert(TSE_IS_REAL_ID(tselem));
+
+    /* The new type design sets the name already, don't override that here. We need to figure out
+     * how to deal with the idcode for non-TSE_SOME_ID types still. Some rely on it... */
+    if (!te->type) {
+      te->name = id->name + 2; /* Default, can be overridden by Library or non-ID data. */
+    }
+    te->idcode = GS(id->name);
+  }
+
+  if (te->type && outliner_tree_element_type_is_expand_valid(te->type)) {
+    outliner_tree_element_type_expand(te->type, space_outliner);
+  }
+  else if (type == TSE_SOME_ID) {
+    /* ID types not (fully) ported to new design yet. */
+    if (outliner_tree_element_type_expand_poll(te->type, space_outliner)) {
+      outliner_add_id_contents(space_outliner, te, tselem, id);
+      outliner_tree_element_type_post_expand(te->type, space_outliner);
+    }
+  }
+  else if (ELEM(type,
+                TSE_ANIM_DATA,
+                TSE_DRIVER_BASE,
+                TSE_NLA,
+                TSE_NLA_ACTION,
+                TSE_NLA_TRACK,
+                TSE_GP_LAYER)) {
+    /* Should already use new AbstractTreeElement design. */
+    BLI_assert(0);
+  }
+  else if (type == TSE_SEQUENCE) {
+    Sequence *seq = (Sequence *)idv;
+
+    /*
+     * The idcode is a little hack, but the outliner
+     * only check te->idcode if te->type is equal to zero,
+     * so this is "safe".
+     */
+    te->idcode = seq->type;
+    te->directdata = seq;
+    te->name = seq->name + 2;
+
+    if (!(seq->type & SEQ_TYPE_EFFECT)) {
+      /*
+       * This work like the sequence.
+       * If the sequence have a name (not default name)
+       * show it, in other case put the filename.
+       */
+
+      if (seq->type == SEQ_TYPE_META) {
+        LISTBASE_FOREACH (Sequence *, p, &seq->seqbase) {
+          outliner_add_element(space_outliner, &te->subtree, (void *)p, te, TSE_SEQUENCE, index);
+        }
+      }
+      else {
+        outliner_add_element(
+            space_outliner, &te->subtree, (void *)seq->strip, te, TSE_SEQ_STRIP, index);
+      }
+    }
+  }
+  else if (type == TSE_SEQ_STRIP) {
+    Strip *strip = (Strip *)idv;
+
+    if (strip->dir[0] != '\0') {
+      te->name = strip->dir;
+    }
+    else {
+      te->name = IFACE_("Strip None");
+    }
+    te->directdata = strip;
+  }
+  else if (type == TSE_SEQUENCE_DUP) {
+    Sequence *seq = (Sequence *)idv;
+
+    te->idcode = seq->type;
+    te->directdata = seq;
+    te->name = seq->strip->stripdata->name;
+  }
+  else if (ELEM(type, TSE_RNA_STRUCT, TSE_RNA_PROPERTY, TSE_RNA_ARRAY_ELEM)) {
+    PointerRNA *ptr = (PointerRNA *)idv;
+
+    /* 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(te->index) == 2, "Index is no longer short!")
+    const int tot_limit = SHRT_MAX;
+
+    /* we do lazy build, for speed and to avoid infinite recursion */
+
+    if (ptr->data == NULL) {
+      te->name = IFACE_("(empty)");
+    }
+    else if (type == TSE_RNA_STRUCT) {
+      /* struct */
+      te->name = RNA_struct_name_get_alloc(ptr, NULL, 0, NULL);
+
+      if (te->name) {
+        te->flag |= TE_FREE_NAME;
+      }
+      else {
+        te->name = RNA_struct_ui_name(ptr->type);
+      }
+
+      /* If searching don't expand RNA entries */
+      if (SEARCHING_OUTLINER(space_outliner) && BLI_strcasecmp("RNA", 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, tot_limit);
+
+      /* auto open these cases */
+      if (!parent || (RNA_property_type(reinterpret_cast<PropertyRNA *>(parent->directdata))) ==
+                         PROP_POINTER) {
+        if (!tselem->used) {
+          tselem->flag &= ~TSE_CLOSED;
+        }
+      }
+
+      if (TSELEM_OPEN(tselem, space_outliner)) {
+        for (int a = 0; a < tot; a++) {
+          PointerRNA propptr;
+          RNA_property_collection_lookup_int(ptr, iterprop, a, &propptr);
+          if (!(RNA_property_flag(reinterpret_cast<PropertyRNA *>(propptr.data)) & PROP_HIDDEN)) {
+            outliner_add_element(
+                space_outliner, &te->subtree, (void *)ptr, te, TSE_RNA_PROPERTY, a);
+          }
+        }
+      }
+      else if (tot) {
+        te->flag |= TE_LAZY_CLOSED;
+      }
+
+      te->rnaptr = *ptr;
+    }
+    else if (type == TSE_RNA_PROPERTY) {
+      /* property */
+      PointerRNA propptr;
+      PropertyRNA *iterprop = RNA_struct_iterator_property(ptr->type);
+      RNA_property_collection_lookup_int(ptr, iterprop, index, &propptr);
+
+      PropertyRNA *prop = reinterpret_cast<PropertyRNA *>(propptr.data);
+      PropertyType proptype = RNA_property_type(prop);
+
+      te->name = RNA_property_ui_name(prop);
+      te->directdata = prop;
+      te->rnaptr = *ptr;
+
+      /* If searching don't expand RNA entries */
+      if (SEARCHING_OUTLINER(space_outliner) && BLI_strcasecmp("RNA", te->name) == 0) {
+        tselem->flag &= ~TSE_CHILDSEARCH;
+      }
+
+      if (proptype == PROP_POINTER) {
+        PointerRNA pptr = RNA_property_pointer_get(ptr, prop);
+
+        if (pptr.data) {
+          if (TSELEM_OPEN(tselem, space_outliner)) {
+            outliner_add_element(
+                space_outliner, &te->subtree, (void *)&pptr, te, TSE_RNA_STRUCT, -1);
+          }
+          else {
+            te->flag |= TE_LAZY_CLOSED;
+          }
+        }
+      }
+      else if (proptype == PROP_COLLECTION) {
+        int tot = RNA_property_collection_length(ptr, prop);
+        CLAMP_MAX(tot, tot_limit);
+
+        if (TSELEM_OPEN(tselem, space_outliner)) {
+          for (int a = 0; a < tot; a++) {
+            PointerRNA pptr;
+            RNA_property_collection_lookup_int(ptr, prop, a, &pptr);
+            outliner_add_element(
+                space_outliner, &te->subtree, (void *)&pptr, te, TSE_RNA_STRUCT, a);
+          }
+        }
+        else if (tot) {
+          te->flag |= TE_LAZY_CLOSED;
+        }
+      }
+      else if (ELEM(proptype, PROP_BOOLEAN, PROP_INT, PROP_FLOAT)) {
+        int tot = RNA_property_array_length(ptr, prop);
+        CLAMP_MAX(tot, tot_limit);
+
+        if (TSELEM_OPEN(tselem, space_outliner)) {
+          for (int a = 0; a < tot; a++) {
+            outliner_add_element(
+                space_outliner, &te->subtree, (void *)ptr, te, TSE_RNA_ARRAY_ELEM, a);
+          }
+        }
+        else if (tot) {
+          te->flag |= TE_LAZY_CLOSED;
+        }
+      }
+    }
+    else if (type == TSE_RNA_ARRAY_ELEM) {
+      PropertyRNA *prop = reinterpret_cast<PropertyRNA *>(parent->directdata);
+
+      te->directdata = prop;
+      te->rnaptr = *ptr;
+      te->index = index;
+
+      char c = RNA_property_array_item_char(prop, index);
+
+      te->name = reinterpret_cast<char *>(MEM_callocN(sizeof(char[20]), "OutlinerRNAArrayName"));
+      if (c) {
+        sprintf((char *)te->name, "  %c", c);
+      }
+      else {
+        sprintf((char *)te->name, "  %d", index + 1);
+      }
+      te->flag |= TE_FREE_NAME;
+    }
+  }
+
+  if (outliner_element_warnings_get(te, NULL, NULL)) {
+    te->flag |= TE_HAS_WARNING;
+  }
+
+  return te;
+}
+
+/* ======================================================= */
+
+BLI_INLINE void outliner_add_collection_init(TreeElement *te, Collection *collection)
+{
+  te->name = BKE_collection_ui_name_get(collection);
+  te->directdata = collection;
+}
+
+BLI_INLINE void outliner_add_collection_objects(SpaceOutliner *space_outliner,
+                                                ListBase *tree,
+                                                Collection *collection,
+                                                TreeElement *parent)
+{
+  LISTBASE_FOREACH (CollectionObject *, cob, &collection->gobject) {
+    outliner_add_element(space_outliner, tree, cob->ob, parent, TSE_SOME_ID, 0);
+  }
+}
+
+TreeElement *outliner_add_collection_recursive(SpaceOutliner *space_outliner,
+                                               Collection *collection,
+                                               TreeElement *ten)
+{
+  outliner_add_collection_init(ten, collection);
+
+  LISTBASE_FOREACH (CollectionChild *, child, &collection->children) {
+    outliner_add_element(
+        space_outliner, &ten->subtree, &child->collection->id, ten, TSE_SOME_ID, 0);
+  }
+
+  if (space_outliner->outlinevis != SO_SCENES) {
+    outliner_add_collection_objects(space_outliner, &ten->subtree, collection, ten);
+  }
+
+  return ten;
+}
+
+/* ======================================================= */
+/* Generic Tree Building helpers - order these are called is top to bottom */
+
+/* Hierarchy --------------------------------------------- */
+
+void outliner_make_object_parent_hierarchy(ListBase *lb)
+{
+  /* build hierarchy */
+  /* XXX also, set extents here... */
+  TreeElement *te = reinterpret_cast<TreeElement *>(lb->first);
+  while (te) {
+    TreeElement *ten = te->next;
+    TreeStoreElem *tselem = TREESTORE(te);
+
+    if ((tselem->type == TSE_SOME_ID) && te->idcode == ID_OB) {
+      Object *ob = (Object *)tselem->id;
+      if (ob->parent && ob->parent->id.newid) {
+        BLI_remlink(lb, te);
+        TreeElement *tep = (TreeElement *)ob->parent->id.newid;
+        BLI_addtail(&tep->subtree, te);
+        te->parent = tep;
+      }
+    }
+    te = ten;
+  }
+}
+
+/* Sorting ------------------------------------------------------ */
+
+typedef struct tTreeSort {
+  TreeElement *te;
+  ID *id;
+  const char *name;
+  short idcode;
+} tTreeSort;
+
+/* alphabetical comparator, trying to put objects first */
+static int treesort_alpha_ob(const void *v1, const void *v2)
+{
+  const tTreeSort *x1 = reinterpret_cast<const tTreeSort *>(v1);
+  const tTreeSort *x2 = reinterpret_cast<const tTreeSort *>(v2);
+
+  /* first put objects last (hierarchy) */
+  int comp = (x1->idcode == ID_OB);
+  if (x2->idcode == ID_OB) {
+    comp += 2;
+  }
+
+  if (comp == 1) {
+    return 1;
+  }
+  if (comp == 2) {
+    return -1;
+  }
+  if (comp == 3) {
+    /* Among objects first come the ones in the collection, followed by the ones not on it.
+     * This way we can have the dashed lines in a separate style connecting the former. */
+    if ((x1->te->flag & TE_CHILD_NOT_IN_COLLECTION) !=
+        (x2->te->flag & TE_CHILD_NOT_IN_COLLECTION)) {
+      return (x1->te->flag & TE_CHILD_NOT_IN_COLLECTION) ? 1 : -1;
+    }
+
+    comp = BLI_strcasecmp_natural(x1->name, x2->name);
+
+    if (comp > 0) {
+      return 1;
+    }
+    if (comp < 0) {
+      return -1;
+    }
+    return 0;
+  }
+  return 0;
+}
+
+/* Move children that are not in the collection to the end of the list. */
+static int treesort_child_not_in_collection(const void *v1, const void *v2)
+{
+  const tTreeSort *x1 = reinterpret_cast<const tTreeSort *>(v1);
+  const tTreeSort *x2 = reinterpret_cast<const tTreeSort *>(v2);
+
+  /* Among objects first come the ones in the collection, followed by the ones not on it.
+   * This way we can have the dashed lines in a separate style connecting the former. */
+  if ((x1->te->flag & TE_CHILD_NOT_IN_COLLECTION) != (x2->te->flag & TE_CHILD_NOT_IN_COLLECTION)) {
+    return (x1->te->flag & TE_CHILD_NOT_IN_COLLECTION) ? 1 : -1;
+  }
+  return 0;
+}
+
+/* alphabetical comparator */
+static int treesort_alpha(const void *v1, const void *v2)
+{
+  const tTreeSort *x1 = reinterpret_cast<const tTreeSort *>(v1);
+  const tTreeSort *x2 = reinterpret_cast<const tTreeSort *>(v2);
+
+  int comp = BLI_strcasecmp_natural(x1->name, x2->name);
+
+  if (comp > 0) {
+    return 1;
+  }
+  if (comp < 0) {
+    return -1;
+  }
+  return 0;
+}
+
+/* this is nice option for later? doesn't look too useful... */
+#if 0
+static int treesort_obtype_alpha(const void *v1, const void *v2)
+{
+  const tTreeSort *x1 = v1, *x2 = v2;
+
+  /* first put objects last (hierarchy) */
+  if (x1->idcode == ID_OB && x2->idcode != ID_OB) {
+    return 1;
+  }
+  else if (x2->idcode == ID_OB && x1->idcode != ID_OB) {
+    return -1;
+  }
+  else {
+    /* 2nd we check ob type */
+    if (x1->idcode == ID_OB && x2->idcode == ID_OB) {
+      if (((Object *)x1->id)->type > ((Object *)x2->id)->type) {
+        return 1;
+      }
+      else if (((Object *)x1->id)->type > ((Object *)x2->id)->type) {
+        return -1;
+      }
+      else {
+        return 0;
+      }
+    }
+    else {
+      int comp = BLI_strcasecmp_natural(x1->name, x2->name);
+
+      if (comp > 0) {
+        return 1;
+      }
+      else if (comp < 0) {
+        return -1;
+      }
+      return 0;
+    }
+  }
+}
+#endif
+
+/* sort happens on each subtree individual */
+static void outliner_sort(ListBase *lb)
+{
+  TreeElement *last_te = reinterpret_cast<TreeElement *>(lb->last);
+  if (last_te == NULL) {
+    return;
+  }
+  TreeStoreElem *last_tselem = TREESTORE(last_te);
+
+  /* Sorting rules; only object lists, ID lists, or deform-groups. */
+  if (ELEM(last_tselem->type, TSE_DEFGROUP, TSE_ID_BASE) ||
+      ((last_tselem->type == TSE_SOME_ID) && (last_te->idcode == ID_OB))) {
+    int totelem = BLI_listbase_count(lb);
+
+    if (totelem > 1) {
+      tTreeSort *tear = reinterpret_cast<tTreeSort *>(
+          MEM_mallocN(totelem * sizeof(tTreeSort), "tree sort array"));
+      tTreeSort *tp = tear;
+      int skip = 0;
+
+      LISTBASE_FOREACH (TreeElement *, te, lb) {
+        TreeStoreElem *tselem = TREESTORE(te);
+        tp->te = te;
+        tp->name = te->name;
+        tp->idcode = te->idcode;
+
+        if (!ELEM(tselem->type, TSE_SOME_ID, TSE_DEFGROUP)) {
+          tp->idcode = 0; /* Don't sort this. */
+        }
+        if (tselem->type == TSE_ID_BASE) {
+          tp->idcode = 1; /* Do sort this. */
+        }
+
+        tp->id = tselem->id;
+        tp++;
+      }
+
+      /* just sort alphabetically */
+      if (tear->idcode == 1) {
+        qsort(tear, totelem, sizeof(tTreeSort), treesort_alpha);
+      }
+      else {
+        /* keep beginning of list */
+        for (tp = tear, skip = 0; skip < totelem; skip++, tp++) {
+          if (tp->idcode) {
+            break;
+          }
+        }
+
+        if (skip < totelem) {
+          qsort(tear + skip, totelem - skip, sizeof(tTreeSort), treesort_alpha_ob);
+        }
+      }
+
+      BLI_listbase_clear(lb);
+      tp = tear;
+      while (totelem--) {
+        BLI_addtail(lb, tp->te);
+        tp++;
+      }
+      MEM_freeN(tear);
+    }
+  }
+
+  LISTBASE_FOREACH (TreeElement *, te_iter, lb) {
+    outliner_sort(&te_iter->subtree);
+  }
+}
+
+static void outliner_collections_children_sort(ListBase *lb)
+{
+  TreeElement *last_te = reinterpret_cast<TreeElement *>(lb->last);
+  if (last_te == NULL) {
+    return;
+  }
+  TreeStoreElem *last_tselem = TREESTORE(last_te);
+
+  /* Sorting rules: only object lists. */
+  if ((last_tselem->type == TSE_SOME_ID) && (last_te->idcode == ID_OB)) {
+    int totelem = BLI_listbase_count(lb);
+
+    if (totelem > 1) {
+      tTreeSort *tear = reinterpret_cast<tTreeSort *>(
+          MEM_mallocN(totelem * sizeof(tTreeSort), "tree sort array"));
+      tTreeSort *tp = tear;
+
+      LISTBASE_FOREACH (TreeElement *, te, lb) {
+        TreeStoreElem *tselem = TREESTORE(te);
+        tp->te = te;
+        tp->name = te->name;
+        tp->idcode = te->idcode;
+        tp->id = tselem->id;
+        tp++;
+      }
+
+      qsort(tear, totelem, sizeof(tTreeSort), treesort_child_not_in_collection);
+
+      BLI_listbase_clear(lb);
+      tp = tear;
+      while (totelem--) {
+        BLI_addtail(lb, tp->te);
+        tp++;
+      }
+      MEM_freeN(tear);
+    }
+  }
+
+  LISTBASE_FOREACH (TreeElement *, te_iter, lb) {
+    outliner_collections_children_sort(&te_iter->subtree);
+  }
+}
+
+/* Filtering ----------------------------------------------- */
+
+typedef struct OutlinerTreeElementFocus {
+  TreeStoreElem *tselem;
+  int ys;
+} OutlinerTreeElementFocus;
+
+/**
+ * Bring the outliner scrolling back to where it was in relation to the original focus element
+ * Caller is expected to handle redrawing of ARegion.
+ */
+static void outliner_restore_scrolling_position(SpaceOutliner *space_outliner,
+                                                ARegion *region,
+                                                OutlinerTreeElementFocus *focus)
+{
+  View2D *v2d = &region->v2d;
+
+  if (focus->tselem != NULL) {
+    outliner_set_coordinates(region, space_outliner);
+
+    TreeElement *te_new = outliner_find_tree_element(&space_outliner->tree, focus->tselem);
+
+    if (te_new != NULL) {
+      int ys_new = te_new->ys;
+      int ys_old = focus->ys;
+
+      float y_move = MIN2(ys_new - ys_old, -v2d->cur.ymax);
+      BLI_rctf_translate(&v2d->cur, 0, y_move);
+    }
+    else {
+      return;
+    }
+  }
+}
+
+static bool test_collection_callback(TreeElement *te)
+{
+  return outliner_is_collection_tree_element(te);
+}
+
+static bool test_object_callback(TreeElement *te)
+{
+  TreeStoreElem *tselem = TREESTORE(te);
+  return ((tselem->type == TSE_SOME_ID) && (te->idcode == ID_OB));
+}
+
+/**
+ * See if TreeElement or any of its children pass the callback_test.
+ */
+static TreeElement *outliner_find_first_desired_element_at_y_recursive(
+    const SpaceOutliner *space_outliner,
+    TreeElement *te,
+    const float limit,
+    bool (*callback_test)(TreeElement *))
+{
+  if (callback_test(te)) {
+    return te;
+  }
+
+  if (TSELEM_OPEN(te->store_elem, space_outliner)) {
+    LISTBASE_FOREACH (TreeElement *, te_iter, &te->subtree) {
+      TreeElement *te_sub = outliner_find_first_desired_element_at_y_recursive(
+          space_outliner, te_iter, limit, callback_test);
+      if (te_sub != NULL) {
+        return te_sub;
+      }
+    }
+  }
+
+  return NULL;
+}
+
+/**
+ * Find the first element that passes a test starting from a reference vertical coordinate
+ *
+ * If the element that is in the position is not what we are looking for, keep looking for its
+ * children, siblings, and eventually, aunts, cousins, distant families, ... etc.
+ *
+ * Basically we keep going up and down the outliner tree from that point forward, until we find
+ * what we are looking for. If we are past the visible range and we can't find a valid element
+ * we return NULL.
+ */
+static TreeElement *outliner_find_first_desired_element_at_y(const SpaceOutliner *space_outliner,
+                                                             const float view_co,
+                                                             const float view_co_limit)
+{
+  TreeElement *te = outliner_find_item_at_y(space_outliner, &space_outliner->tree, view_co);
+
+  bool (*callback_test)(TreeElement *);
+  if ((space_outliner->outlinevis == SO_VIEW_LAYER) &&
+      (space_outliner->filter & SO_FILTER_NO_COLLECTION)) {
+    callback_test = test_object_callback;
+  }
+  else {
+    callback_test = test_collection_callback;
+  }
+
+  while (te != NULL) {
+    TreeElement *te_sub = outliner_find_first_desired_element_at_y_recursive(
+        space_outliner, te, view_co_limit, callback_test);
+    if (te_sub != NULL) {
+      /* Skip the element if it was not visible to start with. */
+      if (te->ys + UI_UNIT_Y > view_co_limit) {
+        return te_sub;
+      }
+      return NULL;
+    }
+
+    if (te->next) {
+      te = te->next;
+      continue;
+    }
+
+    if (te->parent == NULL) {
+      break;
+    }
+
+    while (te->parent) {
+      if (te->parent->next) {
+        te = te->parent->next;
+        break;
+      }
+      te = te->parent;
+    }
+  }
+
+  return NULL;
+}
+
+/**
+ * Store information of current outliner scrolling status to be restored later.
+ *
+ * Finds the top-most collection visible in the outliner and populates the
+ * #OutlinerTreeElementFocus struct to retrieve this element later to make sure it is in the same
+ * original position as before filtering.
+ */
+static void outliner_store_scrolling_position(SpaceOutliner *space_outliner,
+                                              ARegion *region,
+                                              OutlinerTreeElementFocus *focus)
+{
+  float limit = region->v2d.cur.ymin;
+
+  outliner_set_coordinates(region, space_outliner);
+
+  TreeElement *te = outliner_find_first_desired_element_at_y(
+      space_outliner, region->v2d.cur.ymax, limit);
+
+  if (te != NULL) {
+    focus->tselem = TREESTORE(te);
+    focus->ys = te->ys;
+  }
+  else {
+    focus->tselem = NULL;
+  }
+}
+
+static int outliner_exclude_filter_get(const SpaceOutliner *space_outliner)
+{
+  int exclude_filter = space_outliner->filter & ~SO_FILTER_OB_STATE;
+
+  if (space_outliner->search_string[0] != 0) {
+    exclude_filter |= SO_FILTER_SEARCH;
+  }
+  else {
+    exclude_filter &= ~SO_FILTER_SEARCH;
+  }
+
+  /* Let's have this for the collection options at first. */
+  if (!SUPPORT_FILTER_OUTLINER(space_outliner)) {
+    return (exclude_filter & SO_FILTER_SEARCH);
+  }
+
+  if (space_outliner->filter & SO_FILTER_NO_OBJECT) {
+    exclude_filter |= SO_FILTER_OB_TYPE;
+  }
+
+  switch (space_outliner->filter_state) {
+    case SO_FILTER_OB_VISIBLE:
+      exclude_filter |= SO_FILTER_OB_STATE_VISIBLE;
+      break;
+    case SO_FILTER_OB_SELECTED:
+      exclude_filter |= SO_FILTER_OB_STATE_SELECTED;
+      break;
+    case SO_FILTER_OB_ACTIVE:
+      exclude_filter |= SO_FILTER_OB_STATE_ACTIVE;
+      break;
+    case SO_FILTER_OB_SELECTABLE:
+      exclude_filter |= SO_FILTER_OB_STATE_SELECTABLE;
+      break;
+  }
+
+  return exclude_filter;
+}
+
+static bool outliner_element_visible_get(ViewLayer *view_layer,
+                                         TreeElement *te,
+                                         const int exclude_filter)
+{
+  if ((exclude_filter & SO_FILTER_ANY) == 0) {
+    return true;
+  }
+
+  TreeStoreElem *tselem = TREESTORE(te);
+  if ((tselem->type == TSE_SOME_ID) && (te->idcode == ID_OB)) {
+    if ((exclude_filter & SO_FILTER_OB_TYPE) == SO_FILTER_OB_TYPE) {
+      return false;
+    }
+
+    Object *ob = (Object *)tselem->id;
+    Base *base = (Base *)te->directdata;
+    BLI_assert((base == NULL) || (base->object == ob));
+
+    if (exclude_filter & SO_FILTER_OB_TYPE) {
+      switch (ob->type) {
+        case OB_MESH:
+          if (exclude_filter & SO_FILTER_NO_OB_MESH) {
+            return false;
+          }
+          break;
+        case OB_ARMATURE:
+          if (exclude_filter & SO_FILTER_NO_OB_ARMATURE) {
+            return false;
+          }
+          break;
+        case OB_EMPTY:
+          if (exclude_filter & SO_FILTER_NO_OB_EMPTY) {
+            return false;
+          }
+          break;
+        case OB_LAMP:
+          if (exclude_filter & SO_FILTER_NO_OB_LAMP) {
+            return false;
+          }
+          break;
+        case OB_CAMERA:
+          if (exclude_filter & SO_FILTER_NO_OB_CAMERA) {
+            return false;
+          }
+          break;
+        default:
+          if (exclude_filter & SO_FILTER_NO_OB_OTHERS) {
+            return false;
+          }
+          break;
+      }
+    }
+
+    if (exclude_filter & SO_FILTER_OB_STATE) {
+      if (base == NULL) {
+        base = BKE_view_layer_base_find(view_layer, ob);
+
+        if (base == NULL) {
+          return false;
+        }
+      }
+
+      bool is_visible = true;
+      if (exclude_filter & SO_FILTER_OB_STATE_VISIBLE) {
+        if ((base->flag & BASE_VISIBLE_VIEWLAYER) == 0) {
+          is_visible = false;
+        }
+      }
+      else if (exclude_filter & SO_FILTER_OB_STATE_SELECTED) {
+        if ((base->flag & BASE_SELECTED) == 0) {
+          is_visible = false;
+        }
+      }
+      else if (exclude_filter & SO_FILTER_OB_STATE_SELECTABLE) {
+        if ((base->flag & BASE_SELECTABLE) == 0) {
+          is_visible = false;
+        }
+      }
+      else {
+        BLI_assert(exclude_filter & SO_FILTER_OB_STATE_ACTIVE);
+        if (base != BASACT(view_layer)) {
+          is_visible = false;
+        }
+      }
+
+      if (exclude_filter & SO_FILTER_OB_STATE_INVERSE) {
+        is_visible = !is_visible;
+      }
+
+      return is_visible;
+    }
+
+    if ((te->parent != NULL) && (TREESTORE(te->parent)->type == TSE_SOME_ID) &&
+        (te->parent->idcode == ID_OB)) {
+      if (exclude_filter & SO_FILTER_NO_CHILDREN) {
+        return false;
+      }
+    }
+  }
+  else if ((te->parent != NULL) && (TREESTORE(te->parent)->type == TSE_SOME_ID) &&
+           (te->parent->idcode == ID_OB)) {
+    if (exclude_filter & SO_FILTER_NO_OB_CONTENT) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+static bool outliner_filter_has_name(TreeElement *te, const char *name, int flags)
+{
+  int fn_flag = 0;
+
+  if ((flags & SO_FIND_CASE_SENSITIVE) == 0) {
+    fn_flag |= FNM_CASEFOLD;
+  }
+
+  return fnmatch(name, te->name, fn_flag) == 0;
+}
+
+static bool outliner_element_is_collection_or_object(TreeElement *te)
+{
+  TreeStoreElem *tselem = TREESTORE(te);
+
+  if ((tselem->type == TSE_SOME_ID) && (te->idcode == ID_OB)) {
+    return true;
+  }
+
+  /* Collection instance datablocks should not be extracted. */
+  if (outliner_is_collection_tree_element(te) && !(te->parent && te->parent->idcode == ID_OB)) {
+    return true;
+  }
+
+  return false;
+}
+
+static TreeElement *outliner_extract_children_from_subtree(TreeElement *element,
+                                                           ListBase *parent_subtree)
+{
+  TreeElement *te_next = element->next;
+
+  if (outliner_element_is_collection_or_object(element)) {
+    TreeElement *te_prev = NULL;
+    for (TreeElement *te = reinterpret_cast<TreeElement *>(element->subtree.last); te;
+         te = te_prev) {
+      te_prev = te->prev;
+
+      if (!outliner_element_is_collection_or_object(te)) {
+        continue;
+      }
+
+      te_next = te;
+      BLI_remlink(&element->subtree, te);
+      BLI_insertlinkafter(parent_subtree, element->prev, te);
+      te->parent = element->parent;
+    }
+  }
+
+  outliner_free_tree_element(element, parent_subtree);
+  return te_next;
+}
+
+static int outliner_filter_subtree(SpaceOutliner *space_outliner,
+                                   ViewLayer *view_layer,
+                                   ListBase *lb,
+                                   const char *search_string,
+                                   const int exclude_filter)
+{
+  TreeElement *te, *te_next;
+  TreeStoreElem *tselem;
+
+  for (te = reinterpret_cast<TreeElement *>(lb->first); te; te = te_next) {
+    te_next = te->next;
+    if ((outliner_element_visible_get(view_layer, te, exclude_filter) == false)) {
+      /* Don't free the tree, but extract the children from the parent and add to this tree. */
+      /* This also needs filtering the subtree prior (see T69246). */
+      outliner_filter_subtree(
+          space_outliner, view_layer, &te->subtree, search_string, exclude_filter);
+      te_next = outliner_extract_children_from_subtree(te, lb);
+      continue;
+    }
+    if ((exclude_filter & SO_FILTER_SEARCH) == 0) {
+      /* Filter subtree too. */
+      outliner_filter_subtree(
+          space_outliner, view_layer, &te->subtree, search_string, exclude_filter);
+      continue;
+    }
+
+    if (!outliner_filter_has_name(te, search_string, space_outliner->search_flags)) {
+      /* item isn't something we're looking for, but...
+       * - if the subtree is expanded, check if there are any matches that can be easily found
+       *     so that searching for "cu" in the default scene will still match the Cube
+       * - otherwise, we can't see within the subtree and the item doesn't match,
+       *     so these can be safely ignored (i.e. the subtree can get freed)
+       */
+      tselem = TREESTORE(te);
+
+      /* flag as not a found item */
+      tselem->flag &= ~TSE_SEARCHMATCH;
+
+      if ((!TSELEM_OPEN(tselem, space_outliner)) ||
+          outliner_filter_subtree(
+              space_outliner, view_layer, &te->subtree, search_string, exclude_filter) == 0) {
+        outliner_free_tree_element(te, lb);
+      }
+    }
+    else {
+      tselem = TREESTORE(te);
+
+      /* flag as a found item - we can then highlight it */
+      tselem->flag |= TSE_SEARCHMATCH;
+
+      /* filter subtree too */
+      outliner_filter_subtree(
+          space_outliner, view_layer, &te->subtree, search_string, exclude_filter);
+    }
+  }
+
+  /* if there are still items in the list, that means that there were still some matches */
+  return (BLI_listbase_is_empty(lb) == false);
+}
+
+static void outliner_filter_tree(SpaceOutliner *space_outliner, ViewLayer *view_layer)
+{
+  char search_buff[sizeof(((struct SpaceOutliner *)NULL)->search_string) + 2];
+  char *search_string;
+
+  const int exclude_filter = outliner_exclude_filter_get(space_outliner);
+
+  if (exclude_filter == 0) {
+    return;
+  }
+
+  if (space_outliner->search_flags & SO_FIND_COMPLETE) {
+    search_string = space_outliner->search_string;
+  }
+  else {
+    /* Implicitly add heading/trailing wildcards if needed. */
+    BLI_strncpy_ensure_pad(search_buff, space_outliner->search_string, '*', sizeof(search_buff));
+    search_string = search_buff;
+  }
+
+  outliner_filter_subtree(
+      space_outliner, view_layer, &space_outliner->tree, search_string, exclude_filter);
+}
+
+static void outliner_clear_newid_from_main(Main *bmain)
+{
+  ID *id_iter;
+  FOREACH_MAIN_ID_BEGIN (bmain, id_iter) {
+    id_iter->newid = NULL;
+  }
+  FOREACH_MAIN_ID_END;
+}
+
+/* ======================================================= */
+/* Main Tree Building API */
+
+void outliner_build_tree(Main *mainvar,
+                         Scene *scene,
+                         ViewLayer *view_layer,
+                         SpaceOutliner *space_outliner,
+                         ARegion *region)
+{
+  /* Are we looking for something - we want to tag parents to filter child matches
+   * - NOT in data-blocks view - searching all data-blocks takes way too long to be useful
+   * - this variable is only set once per tree build */
+  if (space_outliner->search_string[0] != 0 && space_outliner->outlinevis != SO_DATA_API) {
+    space_outliner->search_flags |= SO_SEARCH_RECURSIVE;
+  }
+  else {
+    space_outliner->search_flags &= ~SO_SEARCH_RECURSIVE;
+  }
+
+  if (space_outliner->runtime->treehash && (space_outliner->storeflag & SO_TREESTORE_REBUILD) &&
+      space_outliner->treestore) {
+    BKE_outliner_treehash_rebuild_from_treestore(space_outliner->runtime->treehash,
+                                                 space_outliner->treestore);
+  }
+  space_outliner->storeflag &= ~SO_TREESTORE_REBUILD;
+
+  if (region->do_draw & RGN_DRAW_NO_REBUILD) {
+    return;
+  }
+
+  OutlinerTreeElementFocus focus;
+  outliner_store_scrolling_position(space_outliner, region, &focus);
+
+  outliner_free_tree(&space_outliner->tree);
+  outliner_storage_cleanup(space_outliner);
+  outliner_tree_display_destroy(&space_outliner->runtime->tree_display);
+
+  space_outliner->runtime->tree_display = outliner_tree_display_create(
+      (eSpaceOutliner_Mode)space_outliner->outlinevis, space_outliner);
+
+  /* All tree displays should be created as sub-classes of AbstractTreeDisplay. */
+  BLI_assert(space_outliner->runtime->tree_display != nullptr);
+
+  TreeSourceData source_data{};
+  source_data.bmain = mainvar;
+  source_data.scene = scene;
+  source_data.view_layer = view_layer;
+  space_outliner->tree = outliner_tree_display_build_tree(space_outliner->runtime->tree_display,
+                                                          &source_data);
+
+  if ((space_outliner->flag & SO_SKIP_SORT_ALPHA) == 0) {
+    outliner_sort(&space_outliner->tree);
+  }
+  else if ((space_outliner->filter & SO_FILTER_NO_CHILDREN) == 0) {
+    /* We group the children that are in the collection before the ones that are not.
+     * This way we can try to draw them in a different style altogether.
+     * We also have to respect the original order of the elements in case alphabetical
+     * sorting is not enabled. This keep object data and modifiers before its children. */
+    outliner_collections_children_sort(&space_outliner->tree);
+  }
+
+  outliner_filter_tree(space_outliner, view_layer);
+  outliner_restore_scrolling_position(space_outliner, region, &focus);
+
+  /* `ID.newid` pointer is abused when building tree, DO NOT call #BKE_main_id_newptr_and_tag_clear
+   * as this expects valid IDs in this pointer, not random unknown data. */
+  outliner_clear_newid_from_main(mainvar);
+}