From 601be0d480b36e62ca60c8241a659c657f1fb09f Mon Sep 17 00:00:00 2001
From: Yuya Nishihara <yuya@tcha.org>
Date: Tue, 28 Nov 2023 10:41:02 +0900
Subject: [PATCH] working_copy: narrow file_states recursively while visiting
 directories
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This saves another ~10ms.

Without watchman:
```
% hyperfine --sort command --warmup 3 --runs 20 -L bin jj-1,jj-2 \
"target/release-with-debug/{bin} -R ~/mirrors/linux files ~/mirrors/linux/no-match"
Benchmark 2: target/release-with-debug/jj-1 -R ~/mirrors/linux files ~/mirrors/linux/no-match
  Time (mean ± σ):     327.7 ms ±  24.9 ms    [User: 1059.1 ms, System: 654.3 ms]
  Range (min … max):   296.0 ms … 385.4 ms    20 runs

Benchmark 3: target/release-with-debug/jj-2 -R ~/mirrors/linux files ~/mirrors/linux/no-match
  Time (mean ± σ):     311.0 ms ±  24.8 ms    [User: 960.0 ms, System: 643.1 ms]
  Range (min … max):   274.9 ms … 358.5 ms    20 runs
```
---
 lib/src/local_working_copy.rs | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/lib/src/local_working_copy.rs b/lib/src/local_working_copy.rs
index 256cab3b4..53135e5dc 100644
--- a/lib/src/local_working_copy.rs
+++ b/lib/src/local_working_copy.rs
@@ -467,10 +467,11 @@ struct FsmonitorMatcher {
     watchman_clock: Option<crate::protos::working_copy::WatchmanClock>,
 }
 
-struct DirectoryToVisit {
+struct DirectoryToVisit<'a> {
     dir: RepoPathBuf,
     disk_dir: PathBuf,
     git_ignore: Arc<GitIgnoreFile>,
+    file_states: FileStates<'a>,
 }
 
 #[derive(Debug, Error)]
@@ -749,6 +750,7 @@ impl TreeState {
                 dir: RepoPathBuf::root(),
                 disk_dir: self.working_copy_path.clone(),
                 git_ignore: base_ignores,
+                file_states: self.file_states.all(),
             };
             self.visit_directory(
                 &matcher,
@@ -837,14 +839,13 @@ impl TreeState {
             dir,
             disk_dir,
             git_ignore,
+            file_states,
         } = directory_to_visit;
 
         if matcher.visit(&dir).is_nothing() {
             return Ok(());
         }
 
-        // TODO: maybe file_states can be narrowed by the dir path?
-        let file_states = self.file_states.all();
         let git_ignore =
             git_ignore.chain_with_file(&dir.to_internal_dir_string(), disk_dir.join(".gitignore"));
         let dir_entries = disk_dir
@@ -881,11 +882,11 @@ impl TreeState {
                 }
 
                 if file_type.is_dir() {
+                    let file_states = file_states.prefixed(&path);
                     if git_ignore.matches(&path.to_internal_dir_string()) {
                         // If the whole directory is ignored, visit only paths we're already
                         // tracking.
-                        let tracked_paths = file_states.prefixed(&path);
-                        for (tracked_path, current_file_state) in tracked_paths {
+                        for (tracked_path, current_file_state) in file_states {
                             if !matcher.matches(tracked_path) {
                                 continue;
                             }
@@ -931,6 +932,7 @@ impl TreeState {
                             dir: path,
                             disk_dir: entry.path(),
                             git_ignore: git_ignore.clone(),
+                            file_states,
                         };
                         self.visit_directory(
                             matcher,