initial commit

semaphore.go

@@ -0,0 +1,31 @@
+package commander
+
+func NewSemaphore(len int) Semaphore {
+	if len == 0 {
+		return nil
+	}
+
+	return make(Semaphore, len)
+}
+
+type Semaphore chan struct{}
+
+func (s Semaphore) Acquire() {
+	if s == nil {
+		return
+	}
+
+	s <- struct{}{}
+}
+
+func (s Semaphore) Release() {
+	if s == nil {
+		return
+	}
+
+	<-s
+}
+
+func (s Semaphore) Close() {
+	close(s)
+}