working end-to-end! bunch of clean up to go

crates/nu-plugin/src/plugin/interface/mod.rs

@@ -11,7 +11,7 @@ use nu_plugin_protocol::{
     ProtocolInfo,
 };
 use nu_protocol::{
-    engine::Closure, Config, LabeledError, PipelineData, PluginSignature, ShellError, Span,
+    engine::{ctrlc, Closure}, Config, LabeledError, PipelineData, PluginSignature, ShellError, Span,
     Spanned, Value,
 };
 use std::{
@@ -59,6 +59,8 @@ struct EngineInterfaceState {
         mpsc::Sender<(EngineCallId, mpsc::Sender<EngineCallResponse<PipelineData>>)>,
     /// The synchronized output writer
     writer: Box<dyn PluginWrite<PluginOutput>>,
+    /// todo: docs
+    ctrlc_handlers: ctrlc::Handlers,
 }
 
 impl std::fmt::Debug for EngineInterfaceState {
@@ -112,6 +114,7 @@ impl EngineInterfaceManager {
                 stream_id_sequence: Sequence::default(),
                 engine_call_subscription_sender: subscription_tx,
                 writer: Box::new(writer),
+                ctrlc_handlers: ctrlc::Handlers::new(),
             }),
             protocol_info_mut,
             plugin_call_sender: Some(plug_tx),
@@ -323,7 +326,7 @@ impl InterfaceManager for EngineInterfaceManager {
                 self.send_engine_call_response(id, response)
             }
             PluginInput::Ctrlc => {
-                eprintln!("Received Ctrl-C!");
+                self.state.ctrlc_handlers.run();
                 Ok(())
             }
         }
@@ -498,6 +501,11 @@ impl EngineInterface {
         self.state.writer.is_stdout()
     }
 
+    /// todo: docs
+    pub fn register_ctrlc_handler(&self, handler: ctrlc::Handler) -> ctrlc::Guard {
+        self.state.ctrlc_handlers.add(handler)
+    }
+
     /// Get the full shell configuration from the engine. As this is quite a large object, it is
     /// provided on request only.
     ///

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

@@ -4,7 +4,7 @@ use std::sync::{
     Arc, Mutex,
 };
 
-type Handler = Box<dyn Fn() + Send + Sync>;
+pub type Handler = Box<dyn Fn() + Send + Sync>;
 
 #[derive(Clone)]
 pub struct Handlers {
@@ -20,6 +20,7 @@ pub struct Guard {
 
 impl Drop for Guard {
     fn drop(&mut self) {
+        eprintln!("Dropping guard: {:?}", self);
         if let Ok(mut handlers) = self.handlers.lock() {
             handlers.retain(|(id, _)| *id != self.id);
         }
@@ -44,6 +45,7 @@ impl Handlers {
         if let Ok(mut handlers) = self.handlers.lock() {
             handlers.push((id, handler));
         }
+        eprintln!("Adding guard: {:?}", id);
         Guard {
             id,
             handlers: Arc::clone(&self.handlers),