emacs_native_async/
lib.rs

1use libc::{kill, pid_t, write, SIGUSR1};
2use parking_lot::Mutex;
3use std::{collections::HashMap, io, sync::atomic::AtomicI64};
4
5pub mod to_lisp;
6
7#[repr(C)]
8pub struct NotificationHandler {
9    pid: pid_t,
10    notify_fd: i32,
11    pending: Mutex<HashMap<i64, emacs::Result<to_lisp::ToLispConvert>>>,
12    id_gen: AtomicI64,
13}
14
15impl NotificationHandler {
16    pub fn new(fd: i32, pid: pid_t) -> NotificationHandler {
17        NotificationHandler {
18            pid,
19            notify_fd: fd,
20            pending: Mutex::new(HashMap::new()),
21            id_gen: AtomicI64::new(0),
22        }
23    }
24
25    pub fn submit<T: Into<to_lisp::ToLispConvert>>(
26        &self,
27        value: emacs::Result<T>,
28        id: i64,
29    ) -> anyhow::Result<()> {
30        self.pending.lock().insert(id, value.map(|v| v.into()));
31        let id = id.to_le_bytes();
32        let mut index: usize = 0;
33        while index != id.len() {
34            let written = unsafe {
35                write(
36                    self.notify_fd,
37                    id.as_ptr().add(index).cast(),
38                    id.len() - index,
39                )
40            };
41            index += usize::try_from(if written == -1 {
42                Err(std::io::Error::last_os_error())
43            } else {
44                Ok(written)
45            }?)?;
46        }
47        Ok(())
48    }
49    pub fn register(&self) -> i64 {
50        self.id_gen
51            .fetch_add(1, std::sync::atomic::Ordering::Relaxed)
52    }
53    pub fn retrieve(&self, id: i64) -> emacs::Result<to_lisp::ToLispConvert> {
54        self.pending
55            .lock()
56            .remove(&id)
57            .ok_or_else(|| anyhow::anyhow!("id not available"))?
58    }
59}
60
61impl Drop for NotificationHandler {
62    fn drop(&mut self) {
63        if -1 == unsafe { kill(self.pid, SIGUSR1) } {
64            eprintln!("error killing child: {}", io::Error::last_os_error())
65        }
66    }
67}
emacs_native_async/lib.rs

emacs_native_async/
lib.rs
