From d06f51a88cb50b9aa9c24445cf17a0a15ffbef4e Mon Sep 17 00:00:00 2001
From: Martin von Zweigbergk <martinvonz@google.com>
Date: Thu, 3 Aug 2023 23:07:11 -0700
Subject: [PATCH] working_copy: split up tracing scope a bit

Now that we process the outputs from the file system traversal by
reading from channels, we can separate the processing from the file
system traversal. When the working copy is unchanged, processing tree
entries and deleted files takes practically no time, but processing
file states and present files takes significant time.
---
 lib/src/working_copy.rs | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/lib/src/working_copy.rs b/lib/src/working_copy.rs
index 439c513d1..69d32231d 100644
--- a/lib/src/working_copy.rs
+++ b/lib/src/working_copy.rs
@@ -656,11 +656,11 @@ impl TreeState {
             disk_dir: self.working_copy_path.clone(),
             git_ignore: base_ignores,
         };
-        trace_span!("traverse filesystem").in_scope(|| -> Result<(), SnapshotError> {
-            let (tree_entries_tx, tree_entries_rx) = channel();
-            let (file_states_tx, file_states_rx) = channel();
-            let (present_files_tx, present_files_rx) = channel();
+        let (tree_entries_tx, tree_entries_rx) = channel();
+        let (file_states_tx, file_states_rx) = channel();
+        let (present_files_tx, present_files_rx) = channel();
 
+        trace_span!("traverse filesystem").in_scope(|| -> Result<(), SnapshotError> {
             self.visit_directory(
                 &matcher,
                 &current_tree,
@@ -669,25 +669,30 @@ impl TreeState {
                 present_files_tx,
                 directory_to_visit,
                 progress,
-            )?;
+            )
+        })?;
 
+        trace_span!("process tree entries").in_scope(|| {
             while let Ok((path, tree_value)) = tree_entries_rx.recv() {
                 tree_builder.set(path, tree_value);
             }
+        });
+        trace_span!("process file states").in_scope(|| {
             while let Ok((path, file_state)) = file_states_rx.recv() {
                 self.file_states.insert(path, file_state);
             }
+        });
+        trace_span!("process present files").in_scope(|| {
             while let Ok(path) = present_files_rx.recv() {
                 deleted_files.remove(&path);
             }
-
-            Ok(())
-        })?;
-
-        for file in &deleted_files {
-            self.file_states.remove(file);
-            tree_builder.remove(file.clone());
-        }
+        });
+        trace_span!("process deleted files").in_scope(|| {
+            for file in &deleted_files {
+                self.file_states.remove(file);
+                tree_builder.remove(file.clone());
+            }
+        });
         let has_changes = tree_builder.has_overrides();
         self.tree_id = tree_builder.write_tree();
         self.watchman_clock = watchman_clock;