io_uring: move fd utility helpers into crate

io-uring/src/timer.rs

@@ -0,0 +1,67 @@
+use {
+    crate::{IoUring, IoUringError},
+    jay_utils::{
+        buf::TypedBuf,
+        oserror::{OsError, OsErrorExt2},
+    },
+    std::{cell::RefCell, rc::Rc, time::Duration},
+    thiserror::Error,
+    uapi::{OwnedFd, c},
+};
+
+#[derive(Debug, Error)]
+pub enum TimerError {
+    #[error("Could not create a timer")]
+    CreateTimer(#[source] OsError),
+    #[error("Could not read from a timer")]
+    TimerReadError(#[source] IoUringError),
+    #[error("Could not set a timer")]
+    SetTimer(#[source] OsError),
+    #[error("The io-uring returned an error")]
+    IoUringError(#[from] IoUringError),
+}
+
+#[derive(Clone)]
+pub struct TimerFd {
+    fd: Rc<OwnedFd>,
+    buf: Rc<RefCell<TypedBuf<u64>>>,
+}
+
+impl TimerFd {
+    pub fn new(clock_id: c::c_int) -> Result<Self, TimerError> {
+        let fd = uapi::timerfd_create(clock_id, c::TFD_CLOEXEC)
+            .map(Rc::new)
+            .map_os_err(TimerError::CreateTimer)?;
+        Ok(Self {
+            fd,
+            buf: Rc::new(RefCell::new(TypedBuf::new())),
+        })
+    }
+
+    #[expect(clippy::await_holding_refcell_ref)]
+    pub async fn expired(&self, ring: &IoUring) -> Result<u64, TimerError> {
+        let mut buf = self.buf.borrow_mut();
+        if let Err(e) = ring.read(&self.fd, buf.buf()).await {
+            return Err(TimerError::TimerReadError(e));
+        }
+        Ok(buf.t())
+    }
+
+    pub fn program(
+        &self,
+        initial: Option<Duration>,
+        periodic: Option<Duration>,
+    ) -> Result<(), TimerError> {
+        let mut timerspec: c::itimerspec = uapi::pod_zeroed();
+        if let Some(init) = initial {
+            timerspec.it_value.tv_sec = init.as_secs() as _;
+            timerspec.it_value.tv_nsec = init.subsec_nanos() as _;
+            if let Some(per) = periodic {
+                timerspec.it_interval.tv_sec = per.as_secs() as _;
+                timerspec.it_interval.tv_nsec = per.subsec_nanos() as _;
+            }
+        }
+        uapi::timerfd_settime(self.fd.raw(), 0, &timerspec).map_os_err(TimerError::SetTimer)?;
+        Ok(())
+    }
+}