toml-config: clear named-action reference cycles

jay-config/Cargo.toml

@@ -17,3 +17,4 @@ backtrace = "0.3.69"
 error_reporter = "1.0.0"
 serde_json = "1.0.114"
 bstr = { version = "1.9.0", default-features = false, features = ["std"] }
+run-on-drop = "1.0.0"

jay-config/src/_private/client.rs

@@ -33,6 +33,7 @@ use {
     },
     bincode::Options,
     futures_util::task::ArcWake,
+    run_on_drop::{OnDrop, on_drop},
     std::{
         cell::{Cell, RefCell},
         collections::{HashMap, VecDeque, hash_map::Entry},
@@ -100,6 +101,7 @@ pub(crate) struct Client {
     on_del_drm_device: RefCell<Option<Callback<DrmDevice>>>,
     on_idle: RefCell<Option<Callback>>,
     on_switch_event: RefCell<HashMap<InputDevice, Callback<SwitchEvent>>>,
+    on_unload: Cell<Option<OnDrop<Box<dyn FnOnce()>>>>,
     bufs: RefCell<Vec<Vec<u8>>>,
     reload: Cell<bool>,
     read_interests: RefCell<HashMap<PollableId, Interest>>,
@@ -232,6 +234,7 @@ pub unsafe extern "C" fn init(
         on_del_drm_device: Default::default(),
         on_idle: Default::default(),
         on_switch_event: Default::default(),
+        on_unload: Default::default(),
         bufs: Default::default(),
         reload: Cell::new(false),
         read_interests: Default::default(),
@@ -1250,6 +1253,12 @@ impl Client {
         }
     }
 
+    pub fn on_unload(&self, f: impl FnOnce() + 'static) {
+        if let Some(prev) = self.on_unload.replace(Some(on_drop(Box::new(f)))) {
+            prev.forget();
+        }
+    }
+
     fn handle_msg(&self, msg: &[u8]) {
         self.handle_msg2(msg);
         self.dispatch_futures();

jay-config/src/lib.rs

@@ -304,3 +304,13 @@ pub fn toggle_float_above_fullscreen() {
 pub fn set_show_float_pin_icon(show: bool) {
     get!().set_show_float_pin_icon(show);
 }
+
+/// Sets a callback to run when this config is unloaded.
+///
+/// Only one callback can be set at a time. If another callback is already set, it will be
+/// dropped without being run.
+///
+/// This function can be used to terminate threads and clear reference cycles.
+pub fn on_unload(f: impl FnOnce() + 'static) {
+    get!().on_unload(f);
+}