Add Outcome::Sleep (#323)

One half of #79

crates/lib/CHANGELOG.md

@@ -31,6 +31,7 @@ First "stable" release of the library.
 - Improvement: the event queue is explicitly closed when shutting down
 - Improvement: the action worker will check if the event queue is closed more often, to shutdown early
 - Improvement: `kill_on_drop` is set on Commands, which will be a little more eager to terminate processes when we're done with them
+- Feature: `Outcome::Sleep` waits for a given duration ([#79](https://github.com/watchexec/watchexec/issues/79))
 
 Other miscellaneous:
 

crates/lib/src/action/outcome.rs

@@ -1,3 +1,5 @@
+use std::time::Duration;
+
 use crate::signal::process::SubSignal;
 
 /// The outcome to execute when an action is triggered.
@@ -26,6 +28,9 @@ pub enum Outcome {
 	/// Does nothing if the command isn't running.
 	Wait,
 
+	/// Sleep for some duration.
+	Sleep(Duration),
+
 	/// Send this signal to the command.
 	///
 	/// This does not wait for the command to complete.

crates/lib/src/action/outcome_worker.rs

@@ -9,6 +9,7 @@ use futures::Future;
 use tokio::{
 	spawn,
 	sync::{mpsc, watch::Receiver},
+	time::sleep,
 };
 use tracing::{debug, error, trace, warn};
 
@@ -153,6 +154,10 @@ impl OutcomeWorker {
 				notry!(self.process.wait())?;
 			}
 
+			(_, Outcome::Sleep(time)) => {
+				notry!(sleep(time));
+			}
+
 			(_, Outcome::Clear) => {
 				clearscreen::clear()?;
 			}