feat(whirl): platform specific signal handling

I hadn't realised until now; the `signal-hook` crate doesn't
function properly on Windows, for the time being; the functionality of
this crate has been disabled on Windows.

This change also adapts the signal handler to use the Tokio-specific
`signal-hook` crate.

2 files changed, 17 insertions, 9 deletions

diff --git a/crates/whirl/Cargo.toml b/crates/whirl/Cargo.toml
index bcf6855..ac24853 100644
--- a/crates/whirl/Cargo.toml
+++ b/crates/whirl/Cargo.toml
@@ -37,7 +37,6 @@ serde_derive = "1.0.127"
 
 # CLI
 structopt = "0.3.22"
-signal-hook = "0.3.9"
 
 # Config
 whirl_config = { path = "../whirl_config" }
@@ -64,3 +63,7 @@ mimalloc = { version = "0.1.26", default-features = false }
 
 [target.'cfg(unix)'.dependencies]
 jemallocator = "0.3.2"
+
+# Signal
+signal-hook = "0.3.9"
+signal-hook-tokio = "0.3.0"
diff --git a/crates/whirl/src/lib.rs b/crates/whirl/src/lib.rs
index 1e3931c..6a0774b 100644
--- a/crates/whirl/src/lib.rs
+++ b/crates/whirl/src/lib.rs
@@ -38,7 +38,10 @@ static GLOBAL: jemallocator::Jemalloc = jemallocator::Jemalloc;
 
 pub mod cli;
 
-use signal_hook::consts::{SIGINT, SIGTERM};
+#[cfg(unix)]
+use signal_hook::consts::signal::{SIGINT, SIGTERM};
+#[cfg(unix)]
+use tokio_stream::StreamExt;
 use whirl_config::Config;
 
 pub struct Whirl;
@@ -80,13 +83,15 @@ impl Whirl {
     }
 
     // Ctrl+C handling
-    tokio::spawn(async move {
-      for signal in signal_hook::iterator::Signals::new(&[SIGTERM, SIGINT])
-        .unwrap()
-        .forever()
-      {
-        info!("signal received: {:?}, killing whirl", signal);
-        std::process::exit(0);
+    #[cfg(unix)]
+    tokio::spawn({
+      while let Some(signal) = signal_hook_tokio::Signals::new(&[SIGTERM, SIGINT]).fuse() {
+        match signal {
+          _ => {
+            info!("signal received: {:?}, killing whirl", signal);
+            std::process::exit(0);
+          }
+        }
       }
     });