prevent deadlock on close (#17)

Author: gammazero

dsqueue.go

@@ -132,7 +132,8 @@ func (q *DSQueue) GetN(n int) ([][]byte, error) {
 	if n == 0 {
 		return nil, nil
 	}
-	rsp := make(chan getResponse)
+	// Buffer response channel so write can happen even if reader gone.
+	rsp := make(chan getResponse, 1)
 	req := getRequest{
 		n:   n,
 		rsp: rsp,

dsqueue_test.go

@@ -414,7 +414,7 @@ func BenchmarkGetN(b *testing.B) {
 	queue := dsqueue.New(ds, dsqName, dsqueue.WithDedupCacheSize(0))
 	defer queue.Close()
 
-	cids := random.Cids(25)
+	cids := random.Cids(64)
 
 	b.ResetTimer()
 	b.ReportAllocs()
@@ -423,7 +423,7 @@ func BenchmarkGetN(b *testing.B) {
 			queue.Put(c.Bytes())
 		}
 
-		outItems, err := queue.GetN(50)
+		outItems, err := queue.GetN(100)
 		if err != nil {
 			b.Fatal(err)
 		}