Function graph_update_columns

graph.c:615–727

}

static void graph_update_columns(struct git_graph *graph)
{
	struct commit_list *parent;
	int max_new_columns;
	int i, seen_this, is_commit_in_columns;

	/*
	 * Swap graph->columns with graph->new_columns
	 * graph->columns contains the state for the previous commit,
	 * and new_columns now contains the state for our commit.
	 *
	 * We'll re-use the old columns array as storage to compute the new
	 * columns list for the commit after this one.
	 */
	SWAP(graph->columns, graph->new_columns);
	graph->num_columns = graph->num_new_columns;
	graph->num_new_columns = 0;

	/*
	 * Now update new_columns and mapping with the information for the
	 * commit after this one.
	 *
	 * First, make sure we have enough room.  At most, there will
	 * be graph->num_columns + graph->num_parents columns for the next
	 * commit.
	 */
	max_new_columns = graph->num_columns + graph->num_parents;
	graph_ensure_capacity(graph, max_new_columns);

	/*
	 * Clear out graph->mapping
	 */
	graph->mapping_size = 2 * max_new_columns;
	for (i = 0; i < graph->mapping_size; i++)
		graph->mapping[i] = -1;

	graph->width = 0;
	graph->prev_edges_added = graph->edges_added;
	graph->edges_added = 0;

	/*
	 * Populate graph->new_columns and graph->mapping
	 *
	 * Some of the parents of this commit may already be in
	 * graph->columns.  If so, graph->new_columns should only contain a
	 * single entry for each such commit.  graph->mapping should
	 * contain information about where each current branch line is
	 * supposed to end up after the collapsing is performed.
	 */
	seen_this = 0;
	is_commit_in_columns = 1;
	for (i = 0; i <= graph->num_columns; i++) {
		struct commit *col_commit;
		if (i == graph->num_columns) {
			if (seen_this)
				break;
			is_commit_in_columns = 0;
			col_commit = graph->commit;