Port forward tree iterator from python to rust.

src/nix_util/running_update.rs

@@ -1,3 +1,5 @@
+use std::borrow::Cow;
+
 use tokio::process::Child;
 use tracing::error;
 
@@ -5,6 +7,7 @@ use crate::Result;
 use crate::nix_util::NixOutputStream;
 use crate::nix_util::nix_output_stream::NixAction;
 use crate::nix_util::output_stream::OutputStream;
+use crate::nix_util::tree_iter::ForwardTreeIter;
 
 use super::activity_tree::ActivityId;
 use super::activity_tree::ActivityTreeEntry;
@@ -113,26 +116,21 @@ impl RunningUpdate {
     fn maybe_print_current_status(&mut self) -> () {}
 
     fn print_current_status(&mut self) -> () {
-        let nodes = self.get_children_in_order(self.activity_tree.get_tree().get_root_id());
+        let nodes = ForwardTreeIter::new(
+            self.activity_tree.get_tree(),
+            None,
+            |entry| true,
+            |entry| false,
+            |entry| true,
+        );
         println!("\n\n\nvvvvvv\n\n");
-        for n in nodes {
-            let activity = n.get_activity();
-            // if activity.is_active() {
-            println!("{:?}", activity.display_name());
-            // }
+        for (depth, is_match, is_transparent, node) in nodes {
+            let name = node
+                .get_activity()
+                .display_name()
+                .unwrap_or(Cow::Borrowed("null"));
+            println!("{depth}\t{is_match}\t{is_transparent}\t{name}");
         }
         println!("\n\n\n^^^^^^\n\n");
     }
-
-    fn get_children_in_order(
-        &self,
-        parent_id: ActivityId,
-    ) -> impl Iterator<Item = &ActivityTreeEntry> {
-        let parent = self.activity_tree.get_tree().get(&parent_id);
-        parent
-            .get_child_ids()
-            .iter()
-            .map(|child_id| self.activity_tree.get_tree().get(child_id))
-            .flat_map(|child| TransparentIter::new(self.activity_tree.get_tree(), child))
-    }
 }