db_visitor: add method playlist()

src/db_print.c

@@ -72,14 +72,51 @@ print_visitor_song_info(struct song *song, void *data,
 	return true;
 }
 
+static bool
+print_visitor_playlist(const struct playlist_metadata *playlist, void *ctx,
+		       G_GNUC_UNUSED GError **error_r)
+{
+	struct client *client = ctx;
+	client_printf(client, "playlist: %s\n", playlist->name);
+	return true;
+}
+
+static bool
+print_visitor_playlist_info(const struct playlist_metadata *playlist,
+			    void *ctx, G_GNUC_UNUSED GError **error_r)
+{
+	struct client *client = ctx;
+	client_printf(client, "playlist: %s\n", playlist->name);
+
+#ifndef G_OS_WIN32
+	struct tm tm;
+#endif
+	char timestamp[32];
+	time_t t = playlist->mtime;
+	strftime(timestamp, sizeof(timestamp),
+#ifdef G_OS_WIN32
+		 "%Y-%m-%dT%H:%M:%SZ",
+		 gmtime(&t)
+#else
+		 "%FT%TZ",
+		 gmtime_r(&t, &tm)
+#endif
+		 );
+	client_printf(client, "Last-Modified: %s\n", timestamp);
+
+	return true;
+}
+
 static const struct db_visitor print_visitor = {
 	.directory = print_visitor_directory,
 	.song = print_visitor_song,
+	.playlist = print_visitor_playlist,
 };
 
 static const struct db_visitor print_info_visitor = {
 	.directory = print_visitor_directory,
 	.song = print_visitor_song_info,
+	.playlist = print_visitor_playlist_info,
 };
 
 struct search_data {

src/db_visitor.h

@@ -22,6 +22,7 @@
 
 struct directory;
 struct song;
+struct playlist_metadata;
 
 struct db_visitor {
 	/**
@@ -38,6 +39,14 @@ struct db_visitor {
 	 * @return true to continue the operation, false on error (set error_r)
 	 */
 	bool (*song)(struct song *song, void *ctx, GError **error_r);
+
+	/**
+	 * Visit a playlist.  Optional method.
+	 *
+	 * @return true to continue the operation, false on error (set error_r)
+	 */
+	bool (*playlist)(const struct playlist_metadata *playlist, void *ctx,
+			 GError **error_r);
 };
 
 #endif

src/directory.c

@@ -184,6 +184,14 @@ directory_walk(const struct directory *directory, bool recursive,
 				return false;
 	}
 
+	if (visitor->playlist != NULL) {
+		const struct playlist_vector *pv = &directory->playlists;
+		for (const struct playlist_metadata *i = pv->head;
+		     i != NULL; i = i->next)
+			if (!visitor->playlist(i, ctx, error_r))
+				return false;
+	}
+
 	const struct dirvec *dv = &directory->children;
 	for (size_t i = 0; i < dv->nr; ++i) {
 		struct directory *child = dv->base[i];