Add notes for the new lead maintainer of the open-source iris project and align with @get-ion/ion by @hiveminded

Former-commit-id: da4f38eb9034daa49446df3ee529423b98f9b331

core/host/world.go

@@ -0,0 +1,61 @@
+package host
+
+import (
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+)
+
+// package-level interrupt notifier and event firing.
+
+type world struct {
+	mu sync.Mutex
+	// onInterrupt contains a list of the functions that should be called when CTRL+C/CMD+C or
+	// a unix kill command received.
+	onInterrupt []func()
+}
+
+var w = &world{}
+
+// RegisterOnInterrupt registers a global function to call when CTRL+C/CMD+C pressed or a unix kill command received.
+func RegisterOnInterrupt(cb func()) {
+	w.mu.Lock()
+	w.onInterrupt = append(w.onInterrupt, cb)
+	w.mu.Unlock()
+}
+
+func notifyInterrupt() {
+	w.mu.Lock()
+	for _, f := range w.onInterrupt {
+		go f()
+	}
+	w.mu.Unlock()
+}
+
+func tryStartInterruptNotifier() {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	if len(w.onInterrupt) > 0 {
+		// this can't be moved to the task interrupt's `Run` function
+		// because it will not catch more than one ctrl/cmd+c, so
+		// we do it here. These tasks are canceled already too.
+		go func() {
+			ch := make(chan os.Signal, 1)
+			signal.Notify(ch,
+				// kill -SIGINT XXXX or Ctrl+c
+				os.Interrupt,
+				syscall.SIGINT, // register that too, it should be ok
+				// os.Kill  is equivalent with the syscall.SIGKILL
+				os.Kill,
+				syscall.SIGKILL, // register that too, it should be ok
+				// kill -SIGTERM XXXX
+				syscall.SIGTERM,
+			)
+			select {
+			case <-ch:
+				notifyInterrupt()
+			}
+		}()
+	}
+}