Additional optimizations: avoid allocations in hot paths

- Optimize Partitions iterator to use as_os_str().len() instead of to_string_lossy().len()
- Optimize normalize_path on Windows to avoid intermediate String allocation when possible

Co-authored-by: j178 <[email protected]>

Author: Copilot

src/fs.rs

@@ -120,8 +120,16 @@ pub(crate) fn normalize_path(path: PathBuf) -> PathBuf {
         *c = b'/';
     }
 
-    let os_str = OsString::from(String::from_utf8_lossy(&path).to_string());
-    PathBuf::from(os_str)
+    // Avoid the intermediate String allocation when possible
+    match String::from_utf8(path) {
+        Ok(s) => PathBuf::from(s),
+        Err(e) => {
+            // Fallback to lossy conversion if not valid UTF-8
+            let path = e.into_bytes();
+            let os_str = OsString::from(String::from_utf8_lossy(&path).into_owned());
+            PathBuf::from(os_str)
+        }
+    }
 }
 
 /// Compute a path describing `path` relative to `base`.

src/run.rs

@@ -107,7 +107,8 @@ impl<'a> Iterator for Partitions<'a> {
 
         while self.current_index < self.filenames.len() {
             let filename = self.filenames[self.current_index];
-            let length = filename.to_string_lossy().len() + 1;
+            // Avoid allocation by computing length directly
+            let length = filename.as_os_str().len() + 1;
 
             if current_length + length > self.max_cli_length
                 || self.current_index - start_index >= self.max_per_batch