Function sort_in_topological_order

commit.c:945–1054

* Performs an in-place topological sort on the list supplied. */

 * Performs an in-place topological sort on the list supplied.
 */
void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
{
	struct commit_list *next, *orig = *list;
	struct commit_list **pptr;
	struct indegree_slab indegree;
	struct prio_queue queue;
	struct commit *commit;
	struct author_date_slab author_date;

	if (!orig)
		return;
	*list = NULL;

	init_indegree_slab(&indegree);
	memset(&queue, '\0', sizeof(queue));

	switch (sort_order) {
	default: /* REV_SORT_IN_GRAPH_ORDER */
		queue.compare = NULL;
		break;
	case REV_SORT_BY_COMMIT_DATE:
		queue.compare = compare_commits_by_commit_date;
		break;
	case REV_SORT_BY_AUTHOR_DATE:
		init_author_date_slab(&author_date);
		queue.compare = compare_commits_by_author_date;
		queue.cb_data = &author_date;
		break;
	}

	/* Mark them and clear the indegree */
	for (next = orig; next; next = next->next) {
		struct commit *commit = next->item;
		*(indegree_slab_at(&indegree, commit)) = 1;
		/* also record the author dates, if needed */
		if (sort_order == REV_SORT_BY_AUTHOR_DATE)
			record_author_date(&author_date, commit);
	}

	/* update the indegree */
	for (next = orig; next; next = next->next) {
		struct commit_list *parents = next->item->parents;
		while (parents) {
			struct commit *parent = parents->item;
			int *pi = indegree_slab_at(&indegree, parent);

			if (*pi)
				(*pi)++;
			parents = parents->next;
		}
	}

	/*
	 * find the tips
	 *
	 * tips are nodes not reachable from any other node in the list
	 *
	 * the tips serve as a starting set for the work queue.