Add a custom stdout for the yes command

src/bin/yes.rs

@@ -1,12 +1,50 @@
+#![allow(unused_attributes)]
+#![feature(can_vector)]
+
 use std::{
     borrow::Cow,
-    io::{BufWriter, Write, stdout},
+    io::{BufWriter, Write},
+    os::fd::BorrowedFd,
 };
 
 use puppyutils::{Result, cli};
+use rustix::{
+    io::{write, writev},
+    stdio::stdout,
+};
+
+#[repr(transparent)]
+struct UnbufStdout<'a> {
+    raw: BorrowedFd<'a>,
+}
+
+impl UnbufStdout<'_> {
+    pub fn new() -> Self {
+        Self { raw: stdout() }
+    }
+}
+
+impl Write for UnbufStdout<'_> {
+    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+        write(self.raw, buf).map_err(std::io::Error::from)
+    }
+
+    fn write_vectored(&mut self, bufs: &[std::io::IoSlice<'_>]) -> std::io::Result<usize> {
+        writev(self.raw, bufs).map_err(std::io::Error::from)
+    }
+
+    #[inline]
+    fn is_write_vectored(&self) -> bool {
+        true
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        Ok(())
+    }
+}
 
 pub fn main() -> Result {
-    let mut stdout = stdout();
+    let mut stdout = UnbufStdout::new();
 
     let mut buffer: Option<String> = None;
 

src/lib.rs

@@ -1,3 +1,5 @@
+#![feature(can_vector)]
+
 use std::{
     borrow::Cow,
     fmt::{Debug, Display},

src/main.rs

@@ -1,3 +1,5 @@
+#![feature(can_vector)]
+
 use std::{borrow::Cow, env::current_exe, os::unix::ffi::OsStrExt, path::PathBuf};
 
 use puppyutils::{Exit, Result};