xwayland: fix logging of stderr

src/utils/line_logger.rs

@@ -0,0 +1,36 @@
+use {
+    crate::{
+        io_uring::{IoUring, IoUringError},
+        utils::{buf::Buf, vecdeque_ext::VecDequeExt},
+    },
+    isnt::std_1::collections::IsntVecDequeExt,
+    std::{collections::VecDeque, rc::Rc},
+    uapi::OwnedFd,
+};
+
+pub async fn log_lines(
+    ring: &IoUring,
+    fd: &Rc<OwnedFd>,
+    mut f: impl FnMut(&[u8], &[u8]),
+) -> Result<(), IoUringError> {
+    let mut buf = VecDeque::<u8>::new();
+    let mut buf2 = Buf::new(1024);
+    let mut done = false;
+    while !done {
+        let n = ring.read(fd, buf2.clone()).await?;
+        buf.extend(&buf2[..n]);
+        if n == 0 {
+            done = true;
+        }
+        while let Some(pos) = buf.iter().position(|b| b == &b'\n') {
+            let (left, right) = buf.get_slices(..pos);
+            f(left, right);
+            buf.drain(..=pos);
+        }
+    }
+    if buf.is_not_empty() {
+        let (left, right) = buf.as_slices();
+        f(left, right);
+    }
+    Ok(())
+}