Outliner: Port pose channel elements to new tree-element code design

No user visible changes expected.

Part of #96713, continuation of work started in 249e4df110 and 2e221de4ce.
Refer to these for a motivation and design overview.

Adds a new class for pose channel elements.

Pull Request: https://projects.blender.org/blender/blender/pulls/111167

source/blender/editors/space_outliner/outliner_intern.hh

@@ -330,6 +330,11 @@ struct ParticleSystemElementCreateData {
   ParticleSystem *psys;
 };
 
+struct PoseChannelElementCreateData {
+  Object *object;
+  bPoseChannel *pchan;
+};
+
 struct PoseGroupElementCreateData {
   Object *object;
   bActionGroup *agrp;

source/blender/editors/space_outliner/outliner_tree.cc

@@ -271,6 +271,9 @@ TreeElement *outliner_add_element(SpaceOutliner *space_outliner,
   else if (type == TSE_R_LAYER) {
     id = &static_cast<ViewLayerElementCreateData *>(idv)->scene->id;
   }
+  else if (type == TSE_POSE_CHANNEL) {
+    id = &static_cast<PoseChannelElementCreateData *>(idv)->object->id;
+  }
   else if (type == TSE_LAYER_COLLECTION) {
     id = &static_cast<LayerCollection *>(idv)->collection->id;
   }
@@ -347,7 +350,7 @@ TreeElement *outliner_add_element(SpaceOutliner *space_outliner,
   else if (ELEM(type, TSE_CONSTRAINT, TSE_CONSTRAINT_BASE)) {
     /* pass */
   }
-  else if (type == TSE_POSE_BASE) {
+  else if (ELEM(type, TSE_POSE_BASE, TSE_POSE_CHANNEL)) {
     /* pass */
   }
   else if (ELEM(type, TSE_POSEGRP, TSE_POSEGRP_BASE)) {
@@ -420,6 +423,7 @@ TreeElement *outliner_add_element(SpaceOutliner *space_outliner,
                 TSE_CONSTRAINT,
                 TSE_CONSTRAINT_BASE,
                 TSE_POSE_BASE,
+                TSE_POSE_CHANNEL,
                 TSE_POSEGRP,
                 TSE_POSEGRP_BASE,
                 TSE_R_LAYER,
@@ -427,9 +431,8 @@ TreeElement *outliner_add_element(SpaceOutliner *space_outliner,
                 TSE_MODIFIER,
                 TSE_MODIFIER_BASE,
                 TSE_GREASE_PENCIL_NODE,
-                TSE_LINKED_OB,
-                TSE_VIEW_COLLECTION_BASE) ||
-           ELEM(type, TSE_LAYER_COLLECTION))
+                TSE_LINKED_OB) ||
+           ELEM(type, TSE_LAYER_COLLECTION, TSE_VIEW_COLLECTION_BASE))
   {
     BLI_assert_msg(false, "Element type should already use new AbstractTreeElement design");
   }

source/blender/editors/space_outliner/tree/tree_element.cc

@@ -165,6 +165,11 @@ std::unique_ptr<AbstractTreeElement> AbstractTreeElement::createFromType(const i
     }
     case TSE_POSE_BASE:
       return std::make_unique<TreeElementPoseBase>(legacy_te, *static_cast<Object *>(idv));
+    case TSE_POSE_CHANNEL: {
+      PoseChannelElementCreateData *pchan_data = static_cast<PoseChannelElementCreateData *>(idv);
+      return std::make_unique<TreeElementPoseChannel>(
+          legacy_te, *pchan_data->object, *pchan_data->pchan);
+    }
     case TSE_POSEGRP_BASE:
       return std::make_unique<TreeElementPoseGroupBase>(legacy_te, *static_cast<Object *>(idv));
     case TSE_POSEGRP: {

source/blender/editors/space_outliner/tree/tree_element_pose.cc

@@ -37,10 +37,10 @@ void TreeElementPoseBase::expand(SpaceOutliner &space_outliner) const
     int const_index = 1000; /* ensure unique id for bone constraints */
     int a;
     LISTBASE_FOREACH_INDEX (bPoseChannel *, pchan, &object_.pose->chanbase, a) {
+      PoseChannelElementCreateData pchan_data = {&object_, pchan};
+
       TreeElement *ten = outliner_add_element(
-          &space_outliner, &legacy_te_.subtree, &object_, &legacy_te_, TSE_POSE_CHANNEL, a);
-      ten->name = pchan->name;
-      ten->directdata = pchan;
+          &space_outliner, &legacy_te_.subtree, &pchan_data, &legacy_te_, TSE_POSE_CHANNEL, a);
       pchan->temp = (void *)ten;
 
       if (!BLI_listbase_is_empty(&pchan->constraints)) {
@@ -78,4 +78,16 @@ void TreeElementPoseBase::expand(SpaceOutliner &space_outliner) const
   }
 }
 
+/* -------------------------------------------------------------------- */
+
+TreeElementPoseChannel::TreeElementPoseChannel(TreeElement &legacy_te,
+                                               Object & /* object */,
+                                               bPoseChannel &pchan)
+    : AbstractTreeElement(legacy_te), /* object_(object), */ pchan_(pchan)
+{
+  BLI_assert(legacy_te.store_elem->type == TSE_POSE_CHANNEL);
+  legacy_te.name = pchan_.name;
+  legacy_te.directdata = &pchan_;
+}
+
 }  // namespace blender::ed::outliner

source/blender/editors/space_outliner/tree/tree_element_pose.hh

@@ -22,4 +22,13 @@ class TreeElementPoseBase final : public AbstractTreeElement {
   void expand(SpaceOutliner &) const override;
 };
 
+class TreeElementPoseChannel final : public AbstractTreeElement {
+  /* Not needed right now, avoid unused member variable warning. */
+  // Object &object_;
+  bPoseChannel &pchan_;
+
+ public:
+  TreeElementPoseChannel(TreeElement &legacy_te, Object &object, bPoseChannel &pchan);
+};
+
 }  // namespace blender::ed::outliner