done

backend/backend.go

@@ -0,0 +1,55 @@
+package backend
+
+import (
+	"io"
+
+	"github.com/jacobsa/go-serial/serial"
+	"github.com/tonychee7000/Arremi/consts"
+)
+
+var (
+	// MidiDev is a global midi device.
+	MidiDev *MIDIDevice
+
+	// MIDIError check this. if not nil, go exit
+	MIDIError error
+)
+
+func init() {
+	MidiDev, MIDIError = NewMIDIDevice()
+}
+
+// Run called by frontend.
+func Run(chSerialName chan string, ch chan int, errCh chan error) {
+	serialName := <-chSerialName
+
+	sPort, err := serial.Open(serial.OpenOptions{
+		PortName:        "/dev/" + serialName,
+		BaudRate:        consts.SerialBaudrate,
+		DataBits:        8,
+		StopBits:        1,
+		ParityMode:      serial.PARITY_NONE,
+		MinimumReadSize: 3,
+	})
+	if err != nil {
+		errCh <- err
+		return
+	}
+	defer MidiDev.AllNoteOff()
+	defer sPort.Close()
+
+	go func() {
+		_, err := io.Copy(MidiDev, sPort)
+		if err != nil {
+			errCh <- err
+		}
+		ch <- 1
+	}()
+
+	for {
+		select {
+		case <-ch:
+			return
+		}
+	}
+}

backend/backend_test.go

@@ -0,0 +1,7 @@
+package backend
+
+import "testing"
+
+func TestBackendRun(t *testing.T) {
+
+}

backend/midiDevice.go

@@ -0,0 +1,50 @@
+package backend
+
+import (
+	"github.com/tonychee7000/Arremi/consts"
+	midi "github.com/youpy/go-coremidi"
+)
+
+// MIDIDevice implies a Writer interface.
+type MIDIDevice struct {
+	client midi.Client
+	source midi.Source
+	Signal chan midi.Packet
+}
+
+// NewMIDIDevice construction func
+func NewMIDIDevice() (*MIDIDevice, error) {
+	var mididev = new(MIDIDevice)
+	err := mididev.Init()
+	return mididev, err
+}
+
+// Init the client and source
+func (midiDev *MIDIDevice) Init() error {
+	var err error
+
+	midiDev.Signal = make(chan midi.Packet, 4096)
+	midiDev.client, err = midi.NewClient(consts.ClientName)
+	if err != nil {
+		return err
+	}
+
+	midiDev.source, err = midi.NewSource(midiDev.client, consts.SourceName)
+	return err
+}
+
+func (midiDev *MIDIDevice) Write(p []byte) (int, error) {
+	var pack = midi.NewPacket(p, 0)
+	midiDev.Signal <- pack
+	err := pack.Received(&(midiDev.source))
+	return len(p), err
+}
+
+// AllNoteOff I don't want panic!
+func (midiDev *MIDIDevice) AllNoteOff() {
+	for i := 0; i < 16; i++ {
+		for j := 0; j < 128; j++ {
+			midiDev.Write([]byte{byte(0x90 + i), byte(j), 0})
+		}
+	}
+}