Simplify the adjust_canonicalization function

src/uu/cp/src/cp.rs

@@ -900,13 +900,15 @@ pub fn normalize_path<P: AsRef<Path>>(path: P) -> PathBuf {
 }
 
 #[cfg(target_os = "windows")]
-fn adjust_canonicalization<'a, P: AsRef<Path>>(p: P) -> Cow<'a, Path> {
+fn adjust_canonicalization<'a, P: 'a + AsRef<Path> + Into<PathBuf>>(p: P) -> Cow<'a, Path> {
+    // In some cases, \\? can be missing some Windows path.
+    // Add it at the beginning
     const VERBATIM_PREFIX: &str = r#"\\?\"#;
-    let p = p.as_ref().display().to_string();
-    if p.starts_with(VERBATIM_PREFIX) {
-        Path::new(&p[VERBATIM_PREFIX.len()..].to_string()).to_path_buf().into()
+    let p_str = p.as_ref().display().to_string();
+    if p_str.starts_with(VERBATIM_PREFIX) {
+        Cow::Owned(p.into())
     } else {
-        Path::new(&p).to_path_buf().into()
+        Path::new(VERBATIM_PREFIX).join(p).into()
     }
 }