feat: initial version of midifi software

This CL introduces the initial version of the midifi software, via
a simplified CLI interface "playsmf".

Though it is far from complete, this version can be manually invoked
with the locations of the MIDI communications port (the `-com` flag),
and MIDI file. It will playback the MIDI file with the correct time.

Software is currently tested with an integration test, that invokes the
program with a known MIDI file and compares the output of the serial
port, standard out, and standard error. Golden files can be updated by
providing the `-test.update-golden` flag.

Change-Id: I312bc721736e2edf385ece5141133ffa6bd20a72
Signed-off-by: Terin Stock <terinjokes@gmail.com>

1 files changed, 79 insertions, 0 deletions

diff --git a/pkg/ttymididrv/out.go b/pkg/ttymididrv/out.go
new file mode 100644
index 0000000..3e16cff
--- /dev/null
+++ b/pkg/ttymididrv/out.go
@@ -0,0 +1,79 @@
+package ttymididrv
+
+import (
+	"sync"
+
+	"github.com/tarm/serial"
+)
+
+type out struct {
+	mu     sync.RWMutex
+	driver *driver
+	port   *serial.Port
+	name   string
+	baud   int
+	closed bool
+	number int
+}
+
+func (o *out) Open() (err error) {
+	o.mu.RLock()
+	if o.closed || o.port != nil {
+		o.mu.RUnlock()
+		return nil
+	}
+	o.mu.RUnlock()
+
+	o.mu.Lock()
+	defer o.mu.Unlock()
+
+	c := &serial.Config{Name: o.name, Baud: o.baud}
+	o.port, err = serial.OpenPort(c)
+	if err != nil {
+		return err
+	}
+
+	o.driver.mu.Lock()
+	o.driver.opened = append(o.driver.opened, o)
+	o.driver.mu.Unlock()
+
+	return nil
+}
+
+func (o *out) Close() error {
+	o.mu.RLock()
+	if o.closed || o.port == nil {
+		o.mu.RUnlock()
+		return nil
+	}
+	o.mu.RUnlock()
+
+	o.mu.Lock()
+	o.closed = true
+	o.mu.Unlock()
+
+	return o.port.Close()
+}
+
+func (o *out) IsOpen() bool {
+	o.mu.RLock()
+	defer o.mu.RUnlock()
+	return !o.closed && o.port != nil
+}
+
+func (o *out) Number() int {
+	return o.number
+}
+
+func (o *out) String() string {
+	return o.name
+}
+
+func (o *out) Underlying() interface{} {
+	return o.port
+}
+
+func (o *out) Send(b []byte) error {
+	_, err := o.port.Write(b)
+	return err
+}