TUN-528: Move cloudflared into a separate repo

h2mux/signal.go

@@ -0,0 +1,34 @@
+package h2mux
+
+// Signal describes an event that can be waited on for at least one signal.
+// Signalling the event while it is in the signalled state is a noop.
+// When the waiter wakes up, the signal is set to unsignalled.
+// It is a way for any number of writers to inform a reader (without blocking)
+// that an event has happened.
+type Signal struct {
+	c chan struct{}
+}
+
+// NewSignal creates a new Signal.
+func NewSignal() Signal {
+	return Signal{c: make(chan struct{}, 1)}
+}
+
+// Signal signals the event.
+func (s Signal) Signal() {
+	// This channel is buffered, so the nonblocking send will always succeed if the buffer is empty.
+	select {
+	case s.c <- struct{}{}:
+	default:
+	}
+}
+
+// Wait for the event to be signalled.
+func (s Signal) Wait() {
+	<-s.c
+}
+
+// WaitChannel returns a channel that is readable after Signal is called.
+func (s Signal) WaitChannel() <-chan struct{} {
+	return s.c
+}