feat: toggle diff explorer and show file change indicators

src/files.rs

@@ -38,6 +38,8 @@ pub struct FileRow<'a> {
     /// The actual project-relative OS path, never reconstructed from the label.
     pub path: &'a Path,
     pub label: &'a str,
+    /// Original virtual-catalog input index; absent for scanned entries and directories.
+    pub catalog_index: Option<usize>,
     pub is_dir: bool,
     pub depth: usize,
     pub expanded: bool,
@@ -48,6 +50,7 @@ struct Node {
     path: PathBuf,
     label: String,
     search_label: String,
+    catalog_index: Option<usize>,
     is_dir: bool,
     parent: Option<usize>,
     children: Vec<usize>,
@@ -153,6 +156,7 @@ impl FilePicker {
                 path,
                 search_label: label.to_lowercase(),
                 label,
+                catalog_index: None,
                 is_dir: entry.file_type().unwrap().is_dir(),
                 parent: None,
                 children: Vec::new(),
@@ -163,25 +167,26 @@ impl FilePicker {
 
     /// Builds the changed-path catalog without consulting the working tree.
     pub fn from_paths(root: PathBuf, paths: impl IntoIterator<Item = PathBuf>) -> Self {
-        let mut catalog = HashSet::new();
-        for path in paths {
+        let mut catalog = HashMap::new();
+        for (index, path) in paths.into_iter().enumerate() {
             for parent in path
                 .ancestors()
                 .skip(1)
                 .filter(|path| !path.as_os_str().is_empty())
             {
-                catalog.insert((parent.to_owned(), true));
+                catalog.insert((parent.to_owned(), true), None);
             }
-            catalog.insert((path, false));
+            catalog.entry((path, false)).or_insert(Some(index));
         }
         let nodes = catalog
             .into_iter()
-            .map(|(path, is_dir)| {
+            .map(|((path, is_dir), catalog_index)| {
                 let label = label(&path);
                 Node {
                     path,
                     search_label: label.to_lowercase(),
                     label,
+                    catalog_index,
                     is_dir,
                     parent: None,
                     children: Vec::new(),
@@ -310,6 +315,7 @@ impl FilePicker {
                     .tree
                     .map_or(node.label.as_str(), |tree| self.tree[tree].label.as_str()),
                 is_dir: node.is_dir,
+                catalog_index: node.catalog_index,
                 depth: row.depth,
                 expanded: row.expanded,
             }
@@ -797,6 +803,30 @@ mod tests {
         picker.reveal_path(Path::new("src/deep/deleted.rs"));
         assert_eq!(picker.accept(), Some(PathBuf::from("src/deep/deleted.rs")));
         assert_eq!(picker.entries().filter(|row| !row.is_dir).count(), 3);
+        let expected_index = |row: &FileRow<'_>| {
+            if row.is_dir {
+                None
+            } else {
+                Some(match row.path.to_str().unwrap() {
+                    "x" => 0,
+                    "x/y" => 1,
+                    "src/deep/deleted.rs" => 2,
+                    path => panic!("unexpected path {path}"),
+                })
+            }
+        };
+        for view in [FileView::List, FileView::Tree] {
+            picker.set_view(view);
+            for query in ["", "x", "deleted"] {
+                picker.query = query.into();
+                picker.refilter();
+                let rows: Vec<_> = picker.entries().collect();
+                assert!(!rows.is_empty());
+                for row in rows {
+                    assert_eq!(row.catalog_index, expected_index(&row));
+                }
+            }
+        }
     }
     use std::sync::atomic::{AtomicU64, Ordering};
 
@@ -831,6 +861,18 @@ mod tests {
             .collect()
     }
 
+    #[test]
+    fn scanned_files_and_directories_have_no_catalog_index() {
+        let directory = Directory::new();
+        directory.put("nested/file.txt", "");
+        let mut picker = directory.scan();
+        for view in [FileView::List, FileView::Tree] {
+            picker.set_view(view);
+            picker.reveal_path(Path::new("nested/file.txt"));
+            assert!(picker.entries().all(|row| row.catalog_index.is_none()));
+        }
+    }
+
     #[test]
     fn nested_ignore_negation_hidden_files_and_vcs_metadata() {
         let directory = Directory::new();