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Co-authored-by: Weihang Lo <weihanglo@users.noreply.github.com>
Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

Author: NobodyXu

src/unix.rs

@@ -17,6 +17,10 @@ use std::thread::{self, Builder, JoinHandle};
 use std::time::Duration;
 
 #[derive(Debug)]
+/// This preserves the `--jobserver-auth` type at creation time,
+/// so auth type will be passed down to and inherit from sub-Make processes correctly.
+///
+/// See <https://github.com/rust-lang/jobserver-rs/issues/99> for details.
 enum ClientCreationArg {
     Fds { read: c_int, write: c_int },
     Fifo(Box<Path>),
@@ -27,8 +31,11 @@ pub struct Client {
     read: File,
     write: File,
     creation_arg: ClientCreationArg,
-    /// it can only go from Some(false) -> Some(true) but not the other way around, since that
-    ///  could cause a race condition.
+    /// It is set to `None` if the pipe is shared with other processesdoes so it cannot support
+    ///  non-blocking mode.
+    ///
+    /// If it is set to `Some`, then It can only go from `Some(false)` -> `Some(true)` but not
+    ///  the other way around, since that could cause a race condition.
     is_non_blocking: Option<AtomicBool>,
 }
 
@@ -115,6 +122,9 @@ impl Client {
         let path = Path::new(path_str);
 
         let open_file = || {
+            // Open with read write is necessary, since open with read-only or
+            // write-only could block the thread until another thread open it
+            // with write-only or read-only (or RDWR) correspondingly.
             OpenOptions::new()
                 .read(true)
                 .write(true)