Function BuildGuiGroupList

src/group_gui.cpp:167–193

* Build GUI group list, a sorted hierarchical list of groups for owner and vehicle type. * @param dst Destination list, owned by the caller. * @param fold Whether to handle group folding/hiding. * @param owner Owner of groups. * @param veh_type Vehicle type of groups. */

 * @param veh_type Vehicle type of groups.
 */
void BuildGuiGroupList(GUIGroupList &list, bool fold, Owner owner, VehicleType veh_type)
{
	/* Make a temporary list of parent groups */
	std::vector<GUIGroupListItem> sublist;
	for (const Group *g : Group::Iterate()) {
		if (g->parent != GroupID::Invalid()) continue;
		if (g->owner != owner) continue;
		if (g->vehicle_type != veh_type) continue;
		sublist.emplace_back(g, 0);
	}
	SortGUIGroupList(sublist);

	/* Now add each parent group, and its children if necessary, to the list. */
	for (auto &item : sublist) {
		GuiGroupListAddChildren(list, list.emplace_back(item), fold);
	}

	if (list.empty()) return;

	/* Hierarchy is complete, traverse in reverse to find where indentation levels continue. */
	uint16_t level_mask = 0;
	for (auto it = std::rbegin(list); std::next(it) != std::rend(list); ++it) {
		auto next_it = std::next(it);
		AssignBit(level_mask, it->indent, it->indent <= next_it->indent);
		next_it->level_mask = level_mask;
	}
}

/* Columns in the group list */
enum VehicleGroupColumns : uint8_t {