Fix concurrency in ivideon

pkg/ivideon/client.go

@@ -18,6 +18,14 @@ import (
 	"time"
 )
 
+type State byte
+
+const (
+	StateNone State = iota
+	StateConn
+	StateHandle
+)
+
 type Client struct {
 	streamer.Element
 
@@ -31,6 +39,7 @@ type Client struct {
 	t0  time.Time
 
 	buffer chan []byte
+	state  State
 	mu     sync.Mutex
 }
 
@@ -69,16 +78,26 @@ func (c *Client) Dial() (err error) {
 		return err
 	}
 
+	c.state = StateConn
+
 	return nil
 }
 
 func (c *Client) Handle() error {
-	c.buffer = make(chan []byte, 5)
 	// add delay to the stream for smooth playing (not a best solution)
 	c.t0 = time.Now().Add(time.Second)
 
-	// processing stream in separate thread for lower delay between packets
-	go c.worker()
+	c.mu.Lock()
+
+	if c.state == StateConn {
+		c.buffer = make(chan []byte, 5)
+		c.state = StateHandle
+
+		// processing stream in separate thread for lower delay between packets
+		go c.worker(c.buffer)
+	}
+
+	c.mu.Unlock()
 
 	_, data, err := c.conn.ReadMessage()
 	if err != nil {
@@ -88,7 +107,7 @@ func (c *Client) Handle() error {
 	track := c.tracks[c.msg.Track]
 	if track != nil {
 		c.mu.Lock()
-		if c.buffer != nil {
+		if c.state == StateHandle {
 			c.buffer <- data
 		}
 		c.mu.Unlock()
@@ -119,7 +138,7 @@ func (c *Client) Handle() error {
 			track = c.tracks[msg.Track]
 			if track != nil {
 				c.mu.Lock()
-				if c.buffer != nil {
+				if c.state == StateHandle {
 					c.buffer <- data
 				}
 				c.mu.Unlock()
@@ -132,15 +151,19 @@ func (c *Client) Handle() error {
 }
 
 func (c *Client) Close() error {
-	if c.conn == nil {
-		return nil
-	}
 	c.mu.Lock()
-	if c.buffer != nil {
+	defer c.mu.Unlock()
+
+	switch c.state {
+	case StateNone:
+		return nil
+	case StateConn:
+	case StateHandle:
 		close(c.buffer)
-		c.buffer = nil
 	}
-	c.mu.Unlock()
+
+	c.state = StateNone
+
 	return c.conn.Close()
 }
 
@@ -220,13 +243,13 @@ func (c *Client) getTracks() error {
 	}
 }
 
-func (c *Client) worker() {
+func (c *Client) worker(buffer chan []byte) {
 	var track *streamer.Track
 	for _, track = range c.tracks {
 		break
 	}
 
-	for data := range c.buffer {
+	for data := range buffer {
 		moof := &fmp4io.MovieFrag{}
 		if _, err := moof.Unmarshal(data, 0); err != nil {
 			continue