Add mutex to ncurses output to avoid race condition at exit

cmd/client.go

@@ -81,6 +81,9 @@ func runClient(cmd *cobra.Command, args []string) {
 		select {
 		case <-c:
 			// funzt noch nicht:
+			log.Println("Got a KILL")
+			con.Close()
+			close(renderQueue)
 			run = false
 		default:
 			if data.GetChar() != 0 {

data/screen.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"sync"
 
 	nc "github.com/rthornton128/goncurses"
 )
@@ -11,23 +12,30 @@ import (
 var (
 	win      *nc.Window
 	ncquit   = make(chan bool)
+	winMutex = &sync.Mutex{}
 )
 
 func RenderFrame(f *Frame) {
+	winMutex.Lock()
+	if win != nil {
 		win.Clear()
 		for k, _ := range f.Data {
-		win.MovePrint(k+1, 1, string(f.Data[k]))
+			win.MovePrint(k, 0, string(f.Data[k]))
 		}
+	}
+	winMutex.Unlock()
 }
 
 func InitNC(killchan chan<- os.Signal) {
 	var err error
+	winMutex.Lock()
 	win, err = nc.Init()
 	if err != nil {
 		log.Fatal(err)
 		os.Exit(1)
 	}
 	win.Timeout(1)
+	winMutex.Unlock()
 	go func() {
 		select {
 		case <-ncquit:
@@ -38,13 +46,18 @@ func InitNC(killchan chan<- os.Signal) {
 }
 
 func ExitNC() {
-	//if win != nil {
+	winMutex.Lock()
+	if win != nil {
+		win = nil
 		nc.End()
 		ncquit <- true
-	//	}
+	}
+	winMutex.Unlock()
 }
 
 func GetChar() int {
+	winMutex.Lock()
+	defer winMutex.Unlock()
 	if win != nil {
 		k := win.GetChar()
 		return int(k)
@@ -52,7 +65,7 @@ func GetChar() int {
 	return 0
 }
 
-func TestNC() (int, int) {
+func testNC() (int, int) {
 	win, err := nc.Init()
 	if err != nil {
 		log.Fatal(err)