+#define SHOWN (1u<<3)
+#define TMP_MARK (1u<<4) /* for isolated cases; clean after use */
+#define BOUNDARY (1u<<5)
+#define BOUNDARY_SHOW (1u<<6)
+#define ADDED (1u<<7) /* Parents already parsed and added? */
+
+struct rev_info;
+
+typedef void (prune_fn_t)(struct rev_info *revs, struct commit *commit);