1 files changed, 61 insertions, 1 deletions
diff --git a/device/channels.go b/device/channels.go
index 4471477..8cd6aee 100644
--- a/device/channels.go
+++ b/device/channels.go
@@ -5,7 +5,10 @@
 
 package device
 
-import "sync"
+import (
+	"runtime"
+	"sync"
+)
 
 // An outboundQueue is a channel of QueueOutboundElements awaiting encryption.
 // An outboundQueue is ref-counted using its wg field.
@@ -67,3 +70,60 @@ func newHandshakeQueue() *handshakeQueue {
 	}()
 	return q
 }
+
+// newAutodrainingInboundQueue returns a channel that will be drained when it gets GC'd.
+// It is useful in cases in which is it hard to manage the lifetime of the channel.
+// The returned channel must not be closed. Senders should signal shutdown using
+// some other means, such as sending a sentinel nil values.
+func newAutodrainingInboundQueue(device *Device) chan *QueueInboundElement {
+	type autodrainingInboundQueue struct {
+		c chan *QueueInboundElement
+	}
+	q := &autodrainingInboundQueue{
+		c: make(chan *QueueInboundElement, QueueInboundSize),
+	}
+	runtime.SetFinalizer(q, func(q *autodrainingInboundQueue) {
+		for {
+			select {
+			case elem := <-q.c:
+				if elem == nil {
+					continue
+				}
+				device.PutMessageBuffer(elem.buffer)
+				device.PutInboundElement(elem)
+			default:
+				return
+			}
+		}
+	})
+	return q.c
+}
+
+// newAutodrainingOutboundQueue returns a channel that will be drained when it gets GC'd.
+// It is useful in cases in which is it hard to manage the lifetime of the channel.
+// The returned channel must not be closed. Senders should signal shutdown using
+// some other means, such as sending a sentinel nil values.
+// All sends to the channel must be best-effort, because there may be no receivers.
+func newAutodrainingOutboundQueue(device *Device) chan *QueueOutboundElement {
+	type autodrainingOutboundQueue struct {
+		c chan *QueueOutboundElement
+	}
+	q := &autodrainingOutboundQueue{
+		c: make(chan *QueueOutboundElement, QueueOutboundSize),
+	}
+	runtime.SetFinalizer(q, func(q *autodrainingOutboundQueue) {
+		for {
+			select {
+			case elem := <-q.c:
+				if elem == nil {
+					continue
+				}
+				device.PutMessageBuffer(elem.buffer)
+				device.PutOutboundElement(elem)
+			default:
+				return
+			}
+		}
+	})
+	return q.c
+}