From a895ee9761a91fbbe23bbc55c2d261cdab5c261f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Krist=C3=B3f=20T=C3=B3th?= <mrtoth@strongds.hu>
Date: Thu, 30 Apr 2020 13:03:06 +0200
Subject: [PATCH] Improve networking code

---
 connection/listen.go | 17 ++++++++++-------
 main.go              |  4 ++--
 2 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/connection/listen.go b/connection/listen.go
index a7a8376..256a5af 100644
--- a/connection/listen.go
+++ b/connection/listen.go
@@ -47,11 +47,12 @@ func listenAndAcceptTCP(address string) (*net.TCPConn, error) {
 	return conn, nil
 }
 
-// Recv returns a read-only channel of byte slices and starts
+// RecvChan returns a read-only channel of byte slices and starts
 // receiving and pushing data into it asynchronously.
 // The channel is closed when the sender closes the connection.
 // Use this to read bytes from the network connection.
-func (c *Connection) Recv() <-chan []byte {
+// The data read is owned by the reader, it is thread-safe to modify.
+func (c *Connection) RecvChan() <-chan []byte {
 	c.recvChan = make(chan []byte)
 	go c.recvLoop()
 	return c.recvChan
@@ -64,11 +65,13 @@ func (c *Connection) recvLoop() {
 		if err != nil {
 			c.stopFlag = true
 		}
-		// the underlying memory of the buffer
-		// must be copied for thread safety
-		sendBuf := make([]byte, n)
-		copy(sendBuf, buf)
-		c.recvChan <- sendBuf
+		if n > 0 {
+			// the underlying memory of the buffer
+			// must be copied for thread safety
+			sendBuf := make([]byte, n)
+			copy(sendBuf, buf)
+			c.recvChan <- sendBuf
+		}
 	}
 	close(c.recvChan)
 }
diff --git a/main.go b/main.go
index 6661a4b..f25c1e3 100644
--- a/main.go
+++ b/main.go
@@ -19,9 +19,9 @@ func socketExample() {
 	defer conn.Close()
 	fmt.Println("Connection accepted!")
 
-	recvChan := conn.Recv()
+	recvChan := conn.RecvChan()
 	go func()  {
-		time.Sleep(30 * time.Second)
+		time.Sleep(10 * time.Second)
 		conn.Close()
 	}()
 	for {