output_plugin: added method "drain"

drain() is the opposite of cancel(): it waits until all data in the
buffer has finished playing.  Instead of implicitly draining in the
close() method like the ALSA plugin has been doing it forever, let the
output thread decide whether to drain or to cancel.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/output_plugin.h b/src/output_plugin.h
index 3a9748d4..ee7f7c73 100644
--- a/src/output_plugin.h
+++ b/src/output_plugin.h
@@ -117,6 +117,11 @@ struct audio_output_plugin {
 		       GError **error);
 
 	/**
+	 * Wait until the device has finished playing.
+	 */
+	void (*drain)(void *data);
+
+	/**
 	 * Try to cancel data which may still be in the device's
 	 * buffers.
 	 */
@@ -214,6 +219,13 @@ ao_plugin_play(const struct audio_output_plugin *plugin,
 }
 
 static inline void
+ao_plugin_drain(const struct audio_output_plugin *plugin, void *data)
+{
+	if (plugin->drain != NULL)
+		plugin->drain(data);
+}
+
+static inline void
 ao_plugin_cancel(const struct audio_output_plugin *plugin, void *data)
 {
 	if (plugin->cancel != NULL)