device/raspivid: implement IsRunning method for raspivid

device/raspivid/raspivid.go

@@ -107,11 +107,12 @@ var AutoWhiteBalanceModes = [...]string{
 // Raspivid is an implementation of AVDevice that provides control over the
 // raspivid command to allow reading of data from a Raspberry Pi camera.
 type Raspivid struct {
-	cfg  config.Config
-	cmd  *exec.Cmd
-	out  io.ReadCloser
-	log  config.Logger
-	done chan struct{}
+	cfg       config.Config
+	cmd       *exec.Cmd
+	out       io.ReadCloser
+	log       config.Logger
+	done      chan struct{}
+	isRunning bool
 }
 
 // New returns a new Raspivid.
@@ -287,6 +288,7 @@ func (r *Raspivid) Start() error {
 	if err != nil {
 		return fmt.Errorf("could not start raspivid command: %w", err)
 	}
+	r.isRunning = true
 
 	return nil
 }
@@ -310,11 +312,11 @@ func (r *Raspivid) Stop() error {
 	if err != nil {
 		return fmt.Errorf("could not kill raspivid process: %w", err)
 	}
+	r.isRunning = false
 	return r.out.Close()
 }
 
 // IsRunning is used to determine if the pi's camera is running.
 func (r *Raspivid) IsRunning() bool {
-	panic("not implemented")
-	return false
+	return r.isRunning
 }