Cleanup: Add & use enum value for ID Outliner element type

Code to check if the Outliner tree-element type was the general ID one
would always check against "0" (explicity or even implicitly). For
somebody unfamiliar with the code this is very confusing. Instead the
value should be given a name, e.g. through an enum.

Adds `TSE_SOME_ID` as the "default" ID tree-element type. Other types
may still represent IDs, as I explained in a comment at the definition.

There may also still be cases where the type is checked against "0". I
noted in the comment that such cases should be cleaned up if found.

1 files changed, 8 insertions, 8 deletions

diff --git a/source/blender/editors/space_outliner/outliner_select.c b/source/blender/editors/space_outliner/outliner_select.c
index e31af48ab7e..d53a37fa60e 100644
--- a/source/blender/editors/space_outliner/outliner_select.c
+++ b/source/blender/editors/space_outliner/outliner_select.c
@@ -198,7 +198,7 @@ void outliner_item_mode_toggle(bContext *C,
 {
   TreeStoreElem *tselem = TREESTORE(te);
 
-  if (tselem->type == 0 && te->idcode == ID_OB) {
+  if ((tselem->type == TSE_SOME_ID) && (te->idcode == ID_OB)) {
     Object *ob = (Object *)tselem->id;
     Base *base = BKE_view_layer_base_find(tvc->view_layer, ob);
 
@@ -301,7 +301,7 @@ static void tree_element_object_activate(bContext *C,
   Object *ob = NULL;
 
   /* if id is not object, we search back */
-  if (tselem->type == 0 && te->idcode == ID_OB) {
+  if ((tselem->type == TSE_SOME_ID) && (te->idcode == ID_OB)) {
     ob = (Object *)tselem->id;
   }
   else {
@@ -443,7 +443,7 @@ static void tree_element_world_activate(bContext *C, Scene *scene, TreeElement *
   TreeElement *tep = te->parent;
   if (tep) {
     TreeStoreElem *tselem = TREESTORE(tep);
-    if (tselem->type == 0) {
+    if (tselem->type == TSE_SOME_ID) {
       sce = (Scene *)tselem->id;
     }
   }
@@ -1165,7 +1165,7 @@ static void outliner_set_properties_tab(bContext *C, TreeElement *te, TreeStoreE
   int context = 0;
 
   /* ID Types */
-  if (tselem->type == 0) {
+  if (tselem->type == TSE_SOME_ID) {
     RNA_id_pointer_create(tselem->id, &ptr);
 
     switch (te->idcode) {
@@ -1374,12 +1374,12 @@ static void do_outliner_item_activate_tree_element(bContext *C,
                                  tvc->scene,
                                  tvc->view_layer,
                                  te,
-                                 (extend && tselem->type == 0) ? OL_SETSEL_EXTEND :
-                                                                 OL_SETSEL_NORMAL,
-                                 recursive && tselem->type == 0);
+                                 (extend && tselem->type == TSE_SOME_ID) ? OL_SETSEL_EXTEND :
+                                                                           OL_SETSEL_NORMAL,
+                                 recursive && tselem->type == TSE_SOME_ID);
   }
 
-  if (tselem->type == 0) { /* The lib blocks. */
+  if (tselem->type == TSE_SOME_ID) { /* The lib blocks. */
     if (do_activate_data == false) {
       /* Only select in outliner. */
     }