Implement ctrlc in place of signal-hook on Windows (#1123)

* Implement ctrlc for Windows

* Add Windows CI workflow

* Fix unused import on Windows by conditionally importing spawn

* Pin ctrlc to =3.4.2 for Debian stable compatibility

.github/workflows/rust.yml

@@ -10,16 +10,19 @@ jobs:
   build:
     name: Build
 
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
 
     strategy:
       matrix:
+        os: [ubuntu-latest, windows-latest]
         build-args:
           [
             --locked --no-default-features,
-            --locked,
-            --locked --features metrics_process,
+            --locked
           ]
+        include:
+          - os: ubuntu-latest
+            build-args: --locked --features metrics_process
 
     steps:
       - uses: actions/checkout@v3

Cargo.toml

@@ -36,9 +36,14 @@ rayon = "1.9"
 serde = "1.0"
 serde_derive = "1.0, <=1.0.171"  # avoid precompiled binaries (https://github.com/serde-rs/serde/issues/2538)
 serde_json = "1.0"
-signal-hook = "0.3"
 tiny_http = { version = "0.12", optional = true }
 
+[target.'cfg(windows)'.dependencies]
+ctrlc = "=3.4.2" 
+
+[target.'cfg(not(windows))'.dependencies]
+signal-hook = "0.3"
+
 [dependencies.electrs-rocksdb]
 version = "0.19.0-e3"
 

src/signals.rs

@@ -1,6 +1,9 @@
+#[cfg(not(windows))]
 use anyhow::Context;
 use crossbeam_channel::{unbounded, Receiver};
+#[cfg(not(windows))]
 use signal_hook::consts::signal::*;
+#[cfg(not(windows))]
 use signal_hook::iterator::Signals;
 
 use std::sync::{
@@ -9,6 +12,7 @@ use std::sync::{
 };
 use std::{error, fmt};
 
+#[cfg(not(windows))]
 use crate::thread::spawn;
 
 #[derive(Debug)]
@@ -53,6 +57,7 @@ pub(crate) struct Signal {
 }
 
 impl Signal {
+    #[cfg(not(windows))]
     pub fn new() -> Signal {
         let ids = vec![
             SIGINT, SIGTERM,
@@ -80,6 +85,27 @@ impl Signal {
         result
     }
 
+    #[cfg(windows)]
+    pub fn new() -> Signal {
+        let (tx, rx) = unbounded();
+        let result = Signal {
+            rx,
+            exit: ExitFlag::new(),
+        };
+
+        let exit_flag = result.exit.clone();
+
+        // Handle Ctrl-C
+        ctrlc::set_handler(move || {
+            info!("notified via Ctrl-C");
+            exit_flag.set();
+            let _ = tx.send(());
+        })
+        .expect("failed to set Ctrl-C handler");
+
+        result
+    }
+
     pub fn receiver(&self) -> &Receiver<()> {
         &self.rx
     }