struct commit *pop_commit(struct commit_list **stack);
int count_parents(struct commit * commit);
+
+/*
+ * Performs an in-place topological sort of list supplied.
+ *
+ * Pre-conditions:
+ * all commits in input list and all parents of those
+ * commits must have object.util == NULL
+ *
+ * Post-conditions:
+ * invariant of resulting list is:
+ * a reachable from b => ord(b) < ord(a)
+ */
+void sort_in_topological_order(struct commit_list ** list);
#endif /* COMMIT_H */