db_print: print extra "playlist" object for embedded CUE sheets

This finally enables the new embedded CUE sheet code: when a song file
contains a playlist, it is printed in the "lsinfo" output, so clients
get to know about this.

NEWS

@@ -4,6 +4,7 @@ ver 0.17 (2011/??/??)
   - "update" and "rescan" need only "CONTROL" permission
   - new command "seekcur" for simpler seeking within current song
   - add range parameter to command "load"
+  - print extra "playlist" object for embedded CUE sheets
 * input:
   - cdio_paranoia: new input plugin to play audio CDs
   - curl: enable CURLOPT_NETRC

src/db_print.c

@@ -56,24 +56,6 @@ print_visitor_directory(const struct directory *directory, void *data,
 	return true;
 }
 
-static bool
-print_visitor_song(struct song *song, void *data,
-		   G_GNUC_UNUSED GError **error_r)
-{
-	struct client *client = data;
-	song_print_uri(client, song);
-	return true;
-}
-
-static bool
-print_visitor_song_info(struct song *song, void *data,
-			G_GNUC_UNUSED GError **error_r)
-{
-	struct client *client = data;
-	song_print_info(client, song);
-	return true;
-}
-
 static void
 print_playlist_in_directory(struct client *client,
 			    const struct directory *directory,
@@ -86,6 +68,42 @@ print_playlist_in_directory(struct client *client,
 			      directory_get_path(directory), name_utf8);
 }
 
+static bool
+print_visitor_song(struct song *song, void *data,
+		   G_GNUC_UNUSED GError **error_r)
+{
+	assert(song != NULL);
+	assert(song->parent != NULL);
+
+	struct client *client = data;
+	song_print_uri(client, song);
+
+	if (song->tag != NULL && song->tag->has_playlist)
+		/* this song file has an embedded CUE sheet */
+		print_playlist_in_directory(client, song->parent,
+					    song->uri);
+
+	return true;
+}
+
+static bool
+print_visitor_song_info(struct song *song, void *data,
+			G_GNUC_UNUSED GError **error_r)
+{
+	assert(song != NULL);
+	assert(song->parent != NULL);
+
+	struct client *client = data;
+	song_print_info(client, song);
+
+	if (song->tag != NULL && song->tag->has_playlist)
+		/* this song file has an embedded CUE sheet */
+		print_playlist_in_directory(client, song->parent,
+					    song->uri);
+
+	return true;
+}
+
 static bool
 print_visitor_playlist(const struct playlist_metadata *playlist,
 		       const struct directory *directory, void *ctx,