audio_output: added method pause()

pause() puts the audio output into pause mode: if supported, it may
perform a special action, which keeps the device open, but does not
play anything.  Output plugins like "shout" might want to play silence
during pause, so their clients won't be disconnected.  Plugins which
do not support pausing will simply be closed, and have to be reopened
when unpaused.

This pach includes an implementation for the shout plugin, which
sends silence chunks.

1 files changed, 18 insertions, 0 deletions

diff --git a/src/output_thread.c b/src/output_thread.c
index 4bc5d8fcb..c2f4f6d3c 100644
--- a/src/output_thread.c
+++ b/src/output_thread.c
@@ -63,6 +63,20 @@ static void ao_play(struct audio_output *ao)
 	ao_command_finished(ao);
 }
 
+static void ao_pause(struct audio_output *ao)
+{
+	if (ao->plugin->pause != NULL) {
+		/* pause is supported */
+		ao_command_finished(ao);
+		ao->plugin->pause(ao->data);
+	} else {
+		/* pause is not supported - simply close the device */
+		ao->plugin->close(ao->data);
+		ao->open = 0;
+		ao_command_finished(ao);
+	}
+}
+
 static void *audio_output_task(void *arg)
 {
 	struct audio_output *ao = arg;
@@ -95,6 +109,10 @@ static void *audio_output_task(void *arg)
 			ao_play(ao);
 			break;
 
+		case AO_COMMAND_PAUSE:
+			ao_pause(ao);
+			break;
+
 		case AO_COMMAND_CANCEL:
 			ao->plugin->cancel(ao->data);
 			ao_command_finished(ao);