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use libc::{kill, pid_t, write, SIGUSR1};
use parking_lot::Mutex;
use std::{collections::HashMap, io, sync::atomic::AtomicI64};
pub mod to_lisp;
#[repr(C)]
pub struct NotificationHandler {
pid: pid_t,
notify_fd: i32,
pending: Mutex<HashMap<i64, emacs::Result<to_lisp::ToLispConvert>>>,
id_gen: AtomicI64,
}
impl NotificationHandler {
pub fn new(fd: i32, pid: pid_t) -> NotificationHandler {
NotificationHandler {
pid,
notify_fd: fd,
pending: Mutex::new(HashMap::new()),
id_gen: AtomicI64::new(0),
}
}
pub fn submit<T: Into<to_lisp::ToLispConvert>>(
&self,
value: emacs::Result<T>,
id: i64,
) -> anyhow::Result<()> {
self.pending.lock().insert(id, value.map(|v| v.into()));
let id = id.to_le_bytes();
let mut index: usize = 0;
while index != id.len() {
let written = unsafe {
write(
self.notify_fd,
id.as_ptr().add(index).cast(),
id.len() - index,
)
};
index += usize::try_from(if written == -1 {
Err(std::io::Error::last_os_error())
} else {
Ok(written)
}?)?;
}
Ok(())
}
pub fn register(&self) -> i64 {
self.id_gen
.fetch_add(1, std::sync::atomic::Ordering::Relaxed)
}
pub fn retrieve(&self, id: i64) -> emacs::Result<to_lisp::ToLispConvert> {
self.pending
.lock()
.remove(&id)
.ok_or_else(|| anyhow::anyhow!("id not available"))?
}
}
impl Drop for NotificationHandler {
fn drop(&mut self) {
if -1 == unsafe { kill(self.pid, SIGUSR1) } {
eprintln!("error killing child: {}", io::Error::last_os_error())
}
}
}