1 files changed, 105 insertions, 0 deletions
diff --git a/vendor/github.com/pion/sctp/ack_timer.go b/vendor/github.com/pion/sctp/ack_timer.go
new file mode 100644
index 0000000..ba23d54
--- /dev/null
+++ b/vendor/github.com/pion/sctp/ack_timer.go
@@ -0,0 +1,105 @@
+package sctp
+
+import (
+	"sync"
+	"time"
+)
+
+const (
+	ackInterval time.Duration = 200 * time.Millisecond
+)
+
+// ackTimerObserver is the inteface to an ack timer observer.
+type ackTimerObserver interface {
+	onAckTimeout()
+}
+
+// ackTimer provides the retnransmission timer conforms with RFC 4960 Sec 6.3.1
+type ackTimer struct {
+	observer ackTimerObserver
+	interval time.Duration
+	stopFunc stopAckTimerLoop
+	closed   bool
+	mutex    sync.RWMutex
+}
+
+type stopAckTimerLoop func()
+
+// newAckTimer creates a new acknowledgement timer used to enable delayed ack.
+func newAckTimer(observer ackTimerObserver) *ackTimer {
+	return &ackTimer{
+		observer: observer,
+		interval: ackInterval,
+	}
+}
+
+// start starts the timer.
+func (t *ackTimer) start() bool {
+	t.mutex.Lock()
+	defer t.mutex.Unlock()
+
+	// this timer is already closed
+	if t.closed {
+		return false
+	}
+
+	// this is a noop if the timer is already running
+	if t.stopFunc != nil {
+		return false
+	}
+
+	cancelCh := make(chan struct{})
+
+	go func() {
+		timer := time.NewTimer(t.interval)
+
+		select {
+		case <-timer.C:
+			t.stop()
+			t.observer.onAckTimeout()
+		case <-cancelCh:
+			timer.Stop()
+		}
+	}()
+
+	t.stopFunc = func() {
+		close(cancelCh)
+	}
+
+	return true
+}
+
+// stops the timer. this is similar to stop() but subsequent start() call
+// will fail (the timer is no longer usable)
+func (t *ackTimer) stop() {
+	t.mutex.Lock()
+	defer t.mutex.Unlock()
+
+	if t.stopFunc != nil {
+		t.stopFunc()
+		t.stopFunc = nil
+	}
+}
+
+// closes the timer. this is similar to stop() but subsequent start() call
+// will fail (the timer is no longer usable)
+func (t *ackTimer) close() {
+	t.mutex.Lock()
+	defer t.mutex.Unlock()
+
+	if t.stopFunc != nil {
+		t.stopFunc()
+		t.stopFunc = nil
+	}
+
+	t.closed = true
+}
+
+// isRunning tests if the timer is running.
+// Debug purpose only
+func (t *ackTimer) isRunning() bool {
+	t.mutex.RLock()
+	defer t.mutex.RUnlock()
+
+	return (t.stopFunc != nil)
+}