From fc50897d2dc2be88ed189aa76e48ba5fc5ff575e Mon Sep 17 00:00:00 2001
From: "Sascha L. Teichmann" <sascha.teichmann@intevation.de>
Date: Sun, 24 Aug 2014 19:27:16 +0200
Subject: [PATCH] interleaver: Run producer and consumer in separate go
 routines.

---
 interleaver/main.go | 33 ++++++++++++++++++++++++---------
 1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/interleaver/main.go b/interleaver/main.go
index 656023e..9efbf98 100644
--- a/interleaver/main.go
+++ b/interleaver/main.go
@@ -49,17 +49,32 @@ func selectKeyEncoder(interleaved bool) common.KeyEncoder {
 }
 
 func copyProducerToConsumer(producer BlockProducer, consumer BlockConsumer) (err error) {
-	var block Block
-	i := 0
-	for {
-		if err = producer.Next(&block); err != nil {
-			if err == ErrNoMoreBlocks {
-				err = nil
-				break
+
+	blocks := make(chan *Block)
+	done := make(chan struct{})
+	defer close(done)
+
+	go func() {
+		defer close(blocks)
+		for {
+			block := new(Block)
+			if err = producer.Next(block); err != nil {
+				if err != ErrNoMoreBlocks {
+					log.Printf("Reading failed: %s\n", err)
+				}
+				return
+			}
+			select {
+			case blocks <- block:
+			case <-done:
+				return
 			}
-			return
 		}
-		if err = consumer.Consume(&block); err != nil {
+	}()
+
+	i := 0
+	for block := range blocks {
+		if err = consumer.Consume(block); err != nil {
 			return
 		}
 		i++