Update to version 8.5.5 | Read HISTORY.md

Former-commit-id: dced7d472edabbab4f80c76051f13261928a8dea

core/host/interrupt.go

@@ -0,0 +1,76 @@
+package host
+
+import (
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+)
+
+// RegisterOnInterrupt registers a global function to call when CTRL+C/CMD+C pressed or a unix kill command received.
+func RegisterOnInterrupt(cb func()) {
+	Interrupt.Register(cb)
+}
+
+// Interrupt watches the os.Signals for interruption signals
+// and fires the callbacks when those happens.
+// A call of its `FireNow` manually will fire and reset the registered interrupt handlers.
+var Interrupt = new(interruptListener)
+
+type interruptListener struct {
+	mu   sync.Mutex
+	once sync.Once
+	// onInterrupt contains a list of the functions that should be called when CTRL+C/CMD+C or
+	// a unix kill command received.
+	onInterrupt []func()
+}
+
+// Register registers a global function to call when CTRL+C/CMD+C pressed or a unix kill command received.
+func (i *interruptListener) Register(cb func()) {
+	if cb == nil {
+		return
+	}
+
+	i.listenOnce()
+	i.mu.Lock()
+	i.onInterrupt = append(i.onInterrupt, cb)
+	i.mu.Unlock()
+}
+
+// FireNow can be called more than one times from a Consumer in order to
+// execute all interrupt handlers manually.
+func (i *interruptListener) FireNow() {
+	i.mu.Lock()
+	for _, f := range i.onInterrupt {
+		f()
+	}
+	i.onInterrupt = i.onInterrupt[0:0]
+	i.mu.Unlock()
+}
+
+// listenOnce fires a goroutine which calls the interrupt handlers when CTRL+C/CMD+C and e.t.c.
+// If `FireNow` called before then it does nothing when interrupt signal received,
+// so it's safe to be used side by side with `FireNow`.
+//
+// Btw this `listenOnce` is called automatically on first register, it's useless for outsiders.
+func (i *interruptListener) listenOnce() {
+	i.once.Do(func() { go i.notifyAndFire() })
+}
+
+func (i *interruptListener) notifyAndFire() {
+	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:
+		i.FireNow()
+	}
+}