Exit gracefully on SIGTERM

* Exit gracefully on `SIGTERM`

Save current state and close ncspot on `SIGTERM`

Fixes #948

* Disable signal handling on non-UNIX platforms

src/main.rs

@@ -18,6 +18,9 @@ use librespot_core::cache::Cache;
 use librespot_playback::audio_backend;
 use log::{error, info, trace};
 
+#[cfg(unix)]
+use signal_hook::{consts::SIGTERM, iterator::Signals};
+
 mod authentication;
 mod command;
 mod commands;
@@ -313,9 +316,22 @@ async fn main() -> Result<(), String> {
 
     cursive.add_fullscreen_layer(layout.with_name("main"));
 
+    // catch SIGTERM to save current state
+    #[cfg(unix)]
+    let mut signals = Signals::new(&[SIGTERM]).expect("could not register SIGTERM handler");
+
     // cursive event loop
     while cursive.is_running() {
         cursive.step();
+        #[cfg(unix)]
+        for signal in signals.pending() {
+            if signal == SIGTERM {
+                info!("Caught SIGTERM, cleaning up and closing");
+                if let Some(data) = cursive.user_data::<UserData>().cloned() {
+                    data.cmd.handle(&mut cursive, Command::Quit);
+                }
+            }
+        }
         for event in event_manager.msg_iter() {
             match event {
                 Event::Player(state) => {