Move ThreadName conversions to &cstr/&str

library/std/src/thread/mod.rs

@@ -1275,7 +1275,9 @@ enum ThreadName {
 
 // This module ensures private fields are kept private, which is necessary to enforce the safety requirements.
 mod thread_name_string {
+ use super::ThreadName;
  use crate::ffi::{CStr, CString};
+ use core::str;
 
  /// Like a `String` it's guaranteed UTF-8 and like a `CString` it's null terminated.
  pub(crate) struct ThreadNameString {
@@ -1294,6 +1296,21 @@ mod thread_name_string {
  }
  }
  }
+ impl ThreadName {
+ pub fn as_cstr(&self) -> Option<&CStr> {
+ match self {
+ ThreadName::Main => Some(c"main"),
+ ThreadName::Other(other) => Some(other),
+ ThreadName::Unnamed => None,
+ }
+ }
+
+ pub fn as_str(&self) -> Option<&str> {
+ // SAFETY: `as_cstr` can only return `Some` for a fixed CStr or a `ThreadNameString`,
+ // which is guaranteed to be UTF-8.
+ self.as_cstr().map(|s| unsafe { str::from_utf8_unchecked(s.to_bytes()) })
+ }
+ }
 }
 pub(crate) use thread_name_string::ThreadNameString;
 
@@ -1472,15 +1489,11 @@ impl Thread {
  #[stable(feature = "rust1", since = "1.0.0")]
  #[must_use]
  pub fn name(&self) -> Option<&str> {
- self.cname().map(|s| unsafe { str::from_utf8_unchecked(s.to_bytes()) })
+ self.inner.name.as_str()
  }
 
  fn cname(&self) -> Option<&CStr> {
- match &self.inner.name {
- ThreadName::Main => Some(c"main"),
- ThreadName::Other(other) => Some(&other),
- ThreadName::Unnamed => None,
- }
+ self.inner.name.as_cstr()
  }
 }