PathBuf::as_mut_vec removed and verified for UEFI and Windows platforms #126333

Author: tnuha

library/std/src/ffi/os_str.rs

@@ -552,15 +552,20 @@ impl OsString {
         OsStr::from_inner_mut(self.inner.leak())
     }
 
-    /// Part of a hack to make PathBuf::push/pop more efficient.
+    /// Provides plumbing to core `Vec::truncate`.
+    /// More well behaving alternative to allowing outer types
+    /// full mutable access to the core `Vec`.
     #[inline]
-    pub(crate) fn as_mut_vec_for_path_buf(&mut self) -> &mut Vec<u8> {
-        self.inner.as_mut_vec_for_path_buf()
+    pub(crate) fn truncate(&mut self, len: usize) {
+        self.inner.truncate(len);
     }
 
+    /// Provides plumbing to core `Vec::extend_from_slice`.
+    /// More well behaving alternative to allowing outer types
+    /// full mutable access to the core `Vec`.
     #[inline]
-    pub(crate) fn truncate(&mut self, len: usize) {
-        self.inner.truncate(len);
+    pub(crate) fn extend_from_slice(&mut self, other: &[u8]) {
+        self.inner.extend_from_slice(other);
     }
 }
 

library/std/src/path.rs

@@ -1163,11 +1163,6 @@ pub struct PathBuf {
 }
 
 impl PathBuf {
-    #[inline]
-    fn as_mut_vec(&mut self) -> &mut Vec<u8> {
-        self.inner.as_mut_vec_for_path_buf()
-    }
-
     /// Allocates an empty `PathBuf`.
     ///
     /// # Examples
@@ -2645,18 +2640,18 @@ impl Path {
             None => {
                 // Enough capacity for the extension and the dot
                 let capacity = self_len + extension.len() + 1;
-                let whole_path = self_bytes.iter();
+                let whole_path = self_bytes;
                 (capacity, whole_path)
             }
             Some(previous_extension) => {
                 let capacity = self_len + extension.len() - previous_extension.len();
-                let path_till_dot = self_bytes[..self_len - previous_extension.len()].iter();
+                let path_till_dot = &self_bytes[..self_len - previous_extension.len()];
                 (capacity, path_till_dot)
             }
         };
 
         let mut new_path = PathBuf::with_capacity(new_capacity);
-        new_path.as_mut_vec().extend(slice_to_copy);
+        new_path.inner.extend_from_slice(slice_to_copy);
         new_path.set_extension(extension);
         new_path
     }

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

@@ -202,15 +202,20 @@ impl Buf {
         self.as_slice().into_rc()
     }
 
-    /// Part of a hack to make PathBuf::push/pop more efficient.
+    /// Provides plumbing to core `Vec::truncate`.
+    /// More well behaving alternative to allowing outer types
+    /// full mutable access to the core `Vec`.
     #[inline]
-    pub(crate) fn as_mut_vec_for_path_buf(&mut self) -> &mut Vec<u8> {
-        &mut self.inner
+    pub(crate) fn truncate(&mut self, len: usize) {
+        self.inner.truncate(len);
     }
 
+    /// Provides plumbing to core `Vec::extend_from_slice`.
+    /// More well behaving alternative to allowing outer types
+    /// full mutable access to the core `Vec`.
     #[inline]
-    pub(crate) fn truncate(&mut self, len: usize) {
-        self.inner.truncate(len);
+    pub(crate) fn extend_from_slice(&mut self, other: &[u8]) {
+        self.inner.extend_from_slice(other);
     }
 }
 

library/std/src/sys/os_str/wtf8.rs

@@ -165,10 +165,20 @@ impl Buf {
         self.as_slice().into_rc()
     }
 
-    /// Part of a hack to make PathBuf::push/pop more efficient.
+    /// Provides plumbing to core `Vec::truncate`.
+    /// More well behaving alternative to allowing outer types
+    /// full mutable access to the core `Vec`.
     #[inline]
-    pub(crate) fn as_mut_vec_for_path_buf(&mut self) -> &mut Vec<u8> {
-        self.inner.as_mut_vec_for_path_buf()
+    pub(crate) fn truncate(&mut self, len: usize) {
+        self.inner.truncate(len);
+    }
+
+    /// Provides plumbing to core `Vec::extend_from_slice`.
+    /// More well behaving alternative to allowing outer types
+    /// full mutable access to the core `Vec`.
+    #[inline]
+    pub(crate) fn extend_from_slice(&mut self, other: &[u8]) {
+        self.inner.extend_from_slice(other);
     }
 }
 

library/std/src/sys_common/wtf8.rs

@@ -474,13 +474,13 @@ impl Wtf8Buf {
         Wtf8Buf { bytes: bytes.into_vec(), is_known_utf8: false }
     }
 
-    /// Part of a hack to make PathBuf::push/pop more efficient.
+    /// Provides plumbing to core `Vec::extend_from_slice`.
+    /// More well behaving alternative to allowing outer types
+    /// full mutable access to the core `Vec`.
     #[inline]
-    pub(crate) fn as_mut_vec_for_path_buf(&mut self) -> &mut Vec<u8> {
-        // FIXME: this function should not even exist, as it implies violating Wtf8Buf invariants
-        // For now, simply assume that is about to happen.
-        self.is_known_utf8 = false;
-        &mut self.bytes
+    pub(crate) fn extend_from_slice(&mut self, other: &[u8]) {
+        self.bytes.extend_from_slice(other);
+        self.is_known_utf8 = self.is_known_utf8 || self.next_surrogate(0).is_none();
     }
 }