add example ctrlc

crates/nu_plugin_example/src/commands/ctrlc.rs

@@ -0,0 +1,52 @@
+use std::sync::{Arc, Barrier};
+
+use nu_plugin::{EngineInterface, EvaluatedCall, PluginCommand};
+use nu_protocol::{Category, LabeledError, PipelineData, Signature};
+
+use crate::ExamplePlugin;
+
+/// `example ctrlc`
+pub struct Ctrlc;
+
+impl PluginCommand for Ctrlc {
+    type Plugin = ExamplePlugin;
+
+    fn name(&self) -> &str {
+        "example ctrlc"
+    }
+
+    fn usage(&self) -> &str {
+        "Example command that demonstrates registering a ctrl-c handler"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build(self.name()).category(Category::Experimental)
+    }
+
+    fn search_terms(&self) -> Vec<&str> {
+        vec!["example"]
+    }
+
+    fn run(
+        &self,
+        _plugin: &ExamplePlugin,
+        engine: &EngineInterface,
+        _call: &EvaluatedCall,
+        _input: PipelineData,
+    ) -> Result<PipelineData, LabeledError> {
+        let barrier = Arc::new(Barrier::new(2));
+
+        let _guard = {
+            let barrier = barrier.clone();
+            engine.register_ctrlc_handler(Box::new(move || {
+                barrier.wait();
+            }))
+        };
+
+        eprintln!("waiting for ctrl-c signal...");
+        barrier.wait();
+        eprintln!("peace.");
+
+        Ok(PipelineData::Empty)
+    }
+}

crates/nu_plugin_example/src/commands/mod.rs

@@ -17,11 +17,13 @@ mod config;
 mod disable_gc;
 mod env;
 mod view_span;
+mod ctrlc;
 
 pub use config::Config;
 pub use disable_gc::DisableGc;
 pub use env::Env;
 pub use view_span::ViewSpan;
+pub use ctrlc::Ctrlc;
 
 // Stream demos
 mod collect_bytes;

crates/nu_plugin_example/src/lib.rs

@@ -23,6 +23,7 @@ impl Plugin for ExamplePlugin {
             Box::new(Env),
             Box::new(ViewSpan),
             Box::new(DisableGc),
+            Box::new(Ctrlc),
             // Stream demos
             Box::new(CollectBytes),
             Box::new(Echo),