🎉 Implement working Audio Mixer backend with Jack support

jack.go

@@ -0,0 +1,62 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/xthexder/go-jack"
+)
+
+var jackClient *jack.Client
+
+func initJack(done chan os.Signal) {
+	jackClient, _ = jack.ClientOpen(config.Jack.ClientName, jack.NoStartServer)
+	if jackClient == nil {
+		fmt.Println("Could not connect to jack server.")
+		return
+	}
+
+	if code := jackClient.SetProcessCallback(processJackCb); code != 0 {
+		fmt.Println("Failed to set process callback.")
+		return
+	}
+
+	if code := jackClient.Activate(); code != 0 {
+		fmt.Println("Failed to activate client:", jack.StrError(code))
+		return
+	}
+}
+
+func stopJack() {
+	jackClient.Close()
+}
+
+func registerJackPort(name string, channels uint8, flags uint64) []*jack.Port {
+	if channels > 2 {
+		fmt.Printf("WARN! Parameters of jack port %s changed: more than 2 channels not implemented, using 2 channels", name)
+		channels = 2
+	}
+
+	var i uint8 = 0
+	var ports []*jack.Port = []*jack.Port{}
+	for i < channels {
+		i++
+		portName := fmt.Sprintf("%s_%d", name, i)
+		port := jackClient.PortRegister(portName, jack.DEFAULT_AUDIO_TYPE, flags, 0)
+		if port == nil {
+			fmt.Printf("WARN! Failed registering jack port %s\n", portName)
+			continue
+		}
+		ports = append(ports, port)
+	}
+	return ports
+}
+
+func unregisterJackPort(ports []*jack.Port) {
+	for _, p := range ports {
+		ret := jackClient.PortUnregister(p)
+		if ret != 0 {
+			fmt.Printf("WARN! Failed unregistering jack port!\n")
+		}
+	}
+}