Pose Library: remove assumption about Action group names

Remove the assumption of the pose library that Action groups are named
after the bones in the armature. Even though this assumption is correct
when the keys are created by Blender, action groups can be renamed. Keys
created by Python scripts can also use arbitrary group names.

Since there is more code in Blender making this assumption, and looping
over selected bones is also a common occurrence, this commit contains
some generic functionality to aid in this:

- `BKE_armature_find_selected_bones`: function that iterates over all
  bones in an armature and calls a callback for each selected one. It
  returns a struct with info about the selection states (all or no bones
  selected).
- `BKE_armature_find_selected_bone_names(armature)` uses the above
  function to return a set of selected bone names.
- `BKE_pose_find_fcurves_with_bones()` calls a callback for each FCurve
  in an Action that targets a bone, also passing it the bone name.

1 files changed, 78 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/armature_selection.cc b/source/blender/blenkernel/intern/armature_selection.cc
new file mode 100644
index 00000000000..c7dbc9d05b1
--- /dev/null
+++ b/source/blender/blenkernel/intern/armature_selection.cc
@@ -0,0 +1,78 @@
+/*
+ * 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 bke
+ */
+
+#include "BKE_armature.hh"
+
+#include "BLI_listbase.h"
+
+#include "DNA_action_types.h"
+#include "DNA_armature_types.h"
+
+namespace blender::bke {
+
+namespace {
+
+void find_selected_bones__visit_bone(const bArmature *armature,
+                                     SelectedBoneCallback callback,
+                                     SelectedBonesResult &result,
+                                     Bone *bone)
+{
+  const bool is_selected = PBONE_SELECTED(armature, bone);
+  result.all_bones_selected &= is_selected;
+  result.no_bones_selected &= !is_selected;
+
+  if (is_selected) {
+    callback(bone);
+  }
+
+  LISTBASE_FOREACH (Bone *, child_bone, &bone->childbase) {
+    find_selected_bones__visit_bone(armature, callback, result, child_bone);
+  }
+}
+}  // namespace
+
+SelectedBonesResult BKE_armature_find_selected_bones(const bArmature *armature,
+                                                     SelectedBoneCallback callback)
+{
+  SelectedBonesResult result;
+  LISTBASE_FOREACH (Bone *, root_bone, &armature->bonebase) {
+    find_selected_bones__visit_bone(armature, callback, result, root_bone);
+  }
+
+  return result;
+}
+
+BoneNameSet BKE_armature_find_selected_bone_names(const bArmature *armature)
+{
+  BoneNameSet selected_bone_names;
+
+  /* Iterate over the selected bones to fill the set of bone names. */
+  auto callback = [&](Bone *bone) { selected_bone_names.add(bone->name); };
+  SelectedBonesResult result = BKE_armature_find_selected_bones(armature, callback);
+
+  /* If no bones are selected, act as if all are. */
+  if (result.all_bones_selected || result.no_bones_selected) {
+    return BoneNameSet();
+  }
+
+  return selected_bone_names;
+}
+
+}  // namespace blender::bke