sketch what adding a broadcast bus to engine_state looks like

Cargo.lock

@@ -516,6 +516,17 @@ version = "3.16.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "79296716171880943b8470b5f8d03aa55eb2e645a4874bdbb28adb49162e012c"
 
+[[package]]
+name = "bus"
+version = "2.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b7118d0221d84fada881b657c2ddb7cd55108db79c8764c9ee212c0c259b783"
+dependencies = [
+ "crossbeam-channel",
+ "num_cpus",
+ "parking_lot_core",
+]
+
 [[package]]
 name = "byte-unit"
 version = "5.1.4"
@@ -2765,6 +2776,7 @@ name = "nu"
 version = "0.94.3"
 dependencies = [
  "assert_cmd",
+ "bus",
  "crossterm",
  "ctrlc",
  "dirs-next",
@@ -3226,6 +3238,7 @@ name = "nu-protocol"
 version = "0.94.3"
 dependencies = [
  "brotli",
+ "bus",
  "byte-unit",
  "chrono",
  "chrono-humanize",

Cargo.toml

@@ -208,6 +208,7 @@ mimalloc = { version = "0.1.42", default-features = false, optional = true }
 serde_json = { workspace = true }
 simplelog = "0.12"
 time = "0.3"
+bus = "2.4.1"
 
 [target.'cfg(not(target_os = "windows"))'.dependencies]
 # Our dependencies don't use OpenSSL on Windows

crates/nu-protocol/Cargo.toml

@@ -33,6 +33,7 @@ serde = { workspace = true, default-features = false }
 thiserror = "1.0"
 typetag = "0.2"
 os_pipe = { workspace = true, features = ["io_safety"] }
+bus = "2.4.1"
 
 [target.'cfg(unix)'.dependencies]
 nix = { workspace = true, default-features = false, features = ["signal"] }

crates/nu-protocol/src/engine/engine_state.rs

@@ -85,6 +85,7 @@ pub struct EngineState {
     usage: Usage,
     pub scope: ScopeFrame,
     pub ctrlc: Option<Arc<AtomicBool>>,
+    pub ctrlc_bus: Option<Arc<Mutex<bus::Bus<()>>>>,
     pub env_vars: Arc<EnvVars>,
     pub previous_env_vars: Arc<HashMap<String, Value>>,
     pub config: Arc<Config>,
@@ -145,6 +146,7 @@ impl EngineState {
                 false,
             ),
             ctrlc: None,
+            ctrlc_bus: None,
             env_vars: Arc::new(
                 [(DEFAULT_OVERLAY_NAME.to_string(), HashMap::new())]
                     .into_iter()

src/main.rs

@@ -35,7 +35,7 @@ use signals::ctrlc_protection;
 use std::{
     path::PathBuf,
     str::FromStr,
-    sync::{atomic::AtomicBool, Arc},
+    sync::{atomic::AtomicBool, Mutex, Arc},
 };
 
 fn get_engine_state() -> EngineState {
@@ -75,8 +75,9 @@ fn main() -> Result<()> {
     }
 
     let ctrlc = Arc::new(AtomicBool::new(false));
+    let ctrlc_bus = Arc::new(Mutex::new(bus::Bus::new(1)));
     // TODO: make this conditional in the future
-    ctrlc_protection(&mut engine_state, &ctrlc);
+    ctrlc_protection(&mut engine_state, &ctrlc, &ctrlc_bus);
 
     // Begin: Default NU_LIB_DIRS, NU_PLUGIN_DIRS
     // Set default NU_LIB_DIRS and NU_PLUGIN_DIRS here before the env.nu is processed. If

src/signals.rs

@@ -1,17 +1,25 @@
 use nu_protocol::engine::EngineState;
 use std::sync::{
     atomic::{AtomicBool, Ordering},
-    Arc,
+    Arc, Mutex,
 };
 
-pub(crate) fn ctrlc_protection(engine_state: &mut EngineState, ctrlc: &Arc<AtomicBool>) {
+pub(crate) fn ctrlc_protection(
+    engine_state: &mut EngineState,
+    ctrlc: &Arc<AtomicBool>,
+    tx: &Arc<Mutex<bus::Bus<()>>>,
+) {
     let handler_ctrlc = ctrlc.clone();
-    let engine_state_ctrlc = ctrlc.clone();
+    let handler_tx = tx.clone();
 
     ctrlc::set_handler(move || {
         handler_ctrlc.store(true, Ordering::SeqCst);
+        if let Ok(mut bus) = handler_tx.lock() {
+            let _ = bus.try_broadcast(());
+        }
     })
     .expect("Error setting Ctrl-C handler");
 
-    engine_state.ctrlc = Some(engine_state_ctrlc);
+    engine_state.ctrlc = Some(ctrlc.clone());
+    engine_state.ctrlc_bus = Some(tx.clone());
 }