tess/
terminal.rs

1use std::io;
2use std::sync::Arc;
3use std::sync::atomic::AtomicBool;
4
5use crossterm::cursor::{Hide, Show};
6use crossterm::terminal::{disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen};
7
8/// RAII guard that enables raw mode + alt screen on construction and restores
9/// the terminal on drop (including during panic unwind).
10pub struct TerminalGuard {
11    mouse: bool,
12}
13
14impl TerminalGuard {
15    pub fn enter(mouse: bool) -> io::Result<Self> {
16        enable_raw_mode()?;
17        crossterm::execute!(io::stdout(), EnterAlternateScreen, Hide)?;
18        if mouse {
19            crossterm::execute!(io::stdout(), crossterm::event::EnableMouseCapture)?;
20        }
21        Ok(TerminalGuard { mouse })
22    }
23}
24
25impl Drop for TerminalGuard {
26    fn drop(&mut self) {
27        if self.mouse {
28            let _ = crossterm::execute!(io::stdout(), crossterm::event::DisableMouseCapture);
29        }
30        let _ = crossterm::execute!(io::stdout(), Show, LeaveAlternateScreen);
31        let _ = disable_raw_mode();
32    }
33}
34
35/// Restore terminal manually (for panic hook). Idempotent and best-effort.
36pub fn restore_terminal_best_effort() {
37    let _ = crossterm::execute!(io::stdout(), Show, LeaveAlternateScreen);
38    let _ = disable_raw_mode();
39}
40
41pub fn install_panic_hook() {
42    let prev = std::panic::take_hook();
43    std::panic::set_hook(Box::new(move |info| {
44        restore_terminal_best_effort();
45        prev(info);
46    }));
47}
48
49/// Returns a flag that becomes `true` on SIGTERM or SIGHUP.
50pub fn install_signal_flag() -> Arc<AtomicBool> {
51    let flag = Arc::new(AtomicBool::new(false));
52    let _ = signal_hook::flag::register(signal_hook::consts::SIGTERM, Arc::clone(&flag));
53    let _ = signal_hook::flag::register(signal_hook::consts::SIGHUP, Arc::clone(&flag));
54    flag
55}
56
57#[cfg(test)]
58mod tests {
59    use super::*;
60    use std::sync::atomic::Ordering;
61
62    #[test]
63    fn signal_flag_starts_false() {
64        let f = install_signal_flag();
65        assert!(!f.load(Ordering::SeqCst));
66    }
67
68    #[test]
69    fn restore_is_idempotent() {
70        // Should not panic when raw mode was never enabled.
71        restore_terminal_best_effort();
72        restore_terminal_best_effort();
73    }
74}
tess/terminal.rs

tess/
terminal.rs
