Remove redundancy and fix padding on some bytes display function

library/core/src/bstr/mod.rs

@@ -155,19 +155,7 @@ unsafe impl DerefPure for ByteStr {}
 #[unstable(feature = "bstr", issue = "134915")]
 impl fmt::Debug for ByteStr {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "\"")?;
-        for chunk in self.utf8_chunks() {
-            for c in chunk.valid().chars() {
-                match c {
-                    '\0' => write!(f, "\\0")?,
-                    '\x01'..='\x7f' => write!(f, "{}", (c as u8).escape_ascii())?,
-                    _ => write!(f, "{}", c.escape_debug())?,
-                }
-            }
-            write!(f, "{}", chunk.invalid().escape_ascii())?;
-        }
-        write!(f, "\"")?;
-        Ok(())
+        fmt::Debug::fmt(&self.utf8_chunks().debug(), f)
     }
 }
 

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

@@ -1,11 +1,11 @@
 //! The underlying OsString/OsStr implementation on Unix and many other
 //! systems: just a `Vec<u8>`/`[u8]`.
 
+use core::bstr::ByteStr;
 use core::clone::CloneToUninit;
 
 use crate::borrow::Cow;
 use crate::collections::TryReserveError;
-use crate::fmt::Write;
 use crate::rc::Rc;
 use crate::sync::Arc;
 use crate::sys::{AsInner, FromInner, IntoInner};
@@ -64,25 +64,7 @@ impl fmt::Debug for Slice {
 
 impl fmt::Display for Slice {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        // If we're the empty string then our iterator won't actually yield
-        // anything, so perform the formatting manually
-        if self.inner.is_empty() {
-            return "".fmt(f);
-        }
-
-        for chunk in self.inner.utf8_chunks() {
-            let valid = chunk.valid();
-            // If we successfully decoded the whole chunk as a valid string then
-            // we can return a direct formatting of the string which will also
-            // respect various formatting flags if possible.
-            if chunk.invalid().is_empty() {
-                return valid.fmt(f);
-            }
-
-            f.write_str(valid)?;
-            f.write_char(char::REPLACEMENT_CHARACTER)?;
-        }
-        Ok(())
+        fmt::Display::fmt(ByteStr::from_bytes(&self.inner), f)
     }
 }