pipewire: Implement capture tear-down

This closes the PipeWire process properly to not leak memory and remove
the PipeWire capture node of soundbox as soon as the context passed to
StreamPipewireContext() is closed.

1 files changed, 40 insertions, 12 deletions

diff --git a/soundbox/pipewire.go b/soundbox/pipewire.go
index 00bbe49..476d2e4 100644
--- a/soundbox/pipewire.go
+++ b/soundbox/pipewire.go
@@ -7,7 +7,6 @@ package soundbox
 import "C"
 
 import (
-	"bytes"
 	"context"
 	"io"
 	"log"
@@ -16,7 +15,41 @@ import (
 	"unsafe"
 )
 
-var pipewireAudio = make(chan []byte, 5)
+type pwCapture struct {
+	cdata unsafe.Pointer
+}
+
+var pwAudio chan []byte
+
+func newPWCapture(ctx context.Context) pwCapture {
+	pwc := pwCapture{}
+
+	pwAudio = make(chan []byte, 5)
+	pwc.cdata = unsafe.Pointer(C.pw_go_capture_init())  // TODO pass &pwc.audio here
+	go C.pw_go_capture_run(pwc.cdata)
+
+	go func() {
+		<-ctx.Done()
+		C.pw_go_capture_deinit(pwc.cdata)
+	}()
+
+	return pwc
+}
+
+func (pwc pwCapture) Read(p []byte) (int, error) {
+	select {
+	case chunk, ok := <-pwAudio:
+		if ok {
+			noSilence := s16leDropSilence(chunk)
+			i := copy(p, noSilence)
+			return i, nil
+		} else {
+			return 0, io.EOF
+		}
+	default:
+		return 0, nil
+	}
+}
 
 func s16leDropSilence(input []byte) []byte {
 	output := make([]byte, 0)
@@ -61,16 +94,11 @@ func StreamPipewireContext(ctx context.Context, targets []net.HardwareAddr) erro
 		return err
 	}
 
-	go C.pw_stdout()
-
+	pwc := newPWCapture(ctx)
 	go func() {
-		for buffer := range pipewireAudio {
-			tempReader := bytes.NewReader(s16leDropSilence(buffer))
-			_, err := io.Copy(stdin, tempReader)
-			if err != nil {
-				log.Println("Failed to copy from PipeWire to ffmpeg.")
-				break
-			}
+		_, err := io.Copy(stdin, pwc)
+		if err != nil {
+			log.Println("Failed to copy from PipeWire to ffmpeg.")
 		}
 	}()
 
@@ -90,5 +118,5 @@ func StreamPipewireContext(ctx context.Context, targets []net.HardwareAddr) erro
 //export goHandleData
 func goHandleData(data *C.int16_t, size C.size_t) {
 	buf := C.GoBytes(unsafe.Pointer(data), C.int(size))
-	pipewireAudio <- buf
+	pwAudio <- buf
 }