inner truncate methods for UEFI platforms

library/std/src/ffi/os_str.rs

@@ -557,6 +557,11 @@ pub fn leak<'a>(self) -> &'a mut OsStr {
     pub(crate) fn as_mut_vec_for_path_buf(&mut self) -> &mut Vec<u8> {
         self.inner.as_mut_vec_for_path_buf()
     }
+
+    #[inline]
+    pub(crate) fn truncate(&mut self, len: usize) {
+        self.inner.truncate(len);
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]

library/std/src/path.rs

@@ -1305,7 +1305,7 @@ fn _push(&mut self, path: &Path) {
 
         // absolute `path` replaces `self`
         if path.is_absolute() || path.prefix().is_some() {
-            self.as_mut_vec().truncate(0);
+            self.inner.truncate(0);
 
         // verbatim paths need . and .. removed
         } else if comps.prefix_verbatim() && !path.inner.is_empty() {
@@ -1350,7 +1350,7 @@ fn _push(&mut self, path: &Path) {
         // `path` has a root but no prefix, e.g., `\windows` (Windows only)
         } else if path.has_root() {
             let prefix_len = self.components().prefix_remaining();
-            self.as_mut_vec().truncate(prefix_len);
+            self.inner.truncate(prefix_len);
 
         // `path` is a pure relative path
         } else if need_sep {
@@ -1383,7 +1383,7 @@ fn _push(&mut self, path: &Path) {
     pub fn pop(&mut self) -> bool {
         match self.parent().map(|p| p.as_u8_slice().len()) {
             Some(len) => {
-                self.as_mut_vec().truncate(len);
+                self.inner.truncate(len);
                 true
             }
             None => false,

library/std/src/sys/os_str/bytes.rs

@@ -207,6 +207,11 @@ pub fn into_rc(&self) -> Rc<Slice> {
     pub(crate) fn as_mut_vec_for_path_buf(&mut self) -> &mut Vec<u8> {
         &mut self.inner
     }
+
+    #[inline]
+    pub(crate) fn truncate(&mut self, len: usize) {
+        self.inner.truncate(len);
+    }
 }
 
 impl Slice {