1 files changed, 24 insertions, 0 deletions
diff --git a/source/blender/blenkernel/intern/node.c b/source/blender/blenkernel/intern/node.c
index 206c59c110a..2eba71fa6bd 100644
--- a/source/blender/blenkernel/intern/node.c
+++ b/source/blender/blenkernel/intern/node.c
@@ -1406,6 +1406,7 @@ bNodeTree *ntreeAddTree(Main *bmain, const char *name, const char *idname)
   }
   else {
     ntree = MEM_callocN(sizeof(bNodeTree), "new node tree");
+    ntree->id.flag |= LIB_PRIVATE_DATA;
     *((short *)ntree->id.name) = ID_NT;
     BLI_strncpy(ntree->id.name + 2, name, sizeof(ntree->id.name));
   }
@@ -2172,6 +2173,7 @@ void ntreeSetOutput(bNodeTree *ntree)
    * might be different for editor or for "real" use... */
 }
 
+/* Returns the private NodeTree object of the datablock, if it has one. */
 bNodeTree *ntreeFromID(const ID *id)
 {
   switch (GS(id->name)) {
@@ -2192,6 +2194,28 @@ bNodeTree *ntreeFromID(const ID *id)
   }
 }
 
+/* Finds and returns the datablock that privately owns the given tree, or NULL. */
+ID *BKE_node_tree_find_owner_ID(Main *bmain, struct bNodeTree *ntree)
+{
+  ListBase *lists[] = {&bmain->materials,
+                       &bmain->lights,
+                       &bmain->worlds,
+                       &bmain->textures,
+                       &bmain->scenes,
+                       &bmain->linestyles,
+                       NULL};
+
+  for (int i = 0; lists[i] != NULL; i++) {
+    LISTBASE_FOREACH (ID *, id, lists[i]) {
+      if (ntreeFromID(id) == ntree) {
+        return id;
+      }
+    }
+  }
+
+  return NULL;
+}
+
 void ntreeMakeLocal(Main *bmain, bNodeTree *ntree, bool id_in_mainlist, const bool lib_local)
 {
   BKE_id_make_local_generic(bmain, &ntree->id, id_in_mainlist, lib_local);