restriction_parser.cpp

#include "extractor/restriction_parser.hpp"
#include "extractor/profile_properties.hpp"

#include "util/conditional_restrictions.hpp"
#include "util/integer_range.hpp"
#include "util/log.hpp"

#include <boost/algorithm/string/predicate.hpp>
#include <boost/optional/optional.hpp>
#include <boost/ref.hpp>

#include <osmium/osm.hpp>

#include <algorithm>

namespace osrm::extractor
{

RestrictionParser::RestrictionParser(bool use_turn_restrictions_,
                                     bool parse_conditionals_,
                                     const std::vector<std::string> &restrictions_)
    : use_turn_restrictions(use_turn_restrictions_), parse_conditionals(parse_conditionals_),
      restrictions(restrictions_.begin(), restrictions_.end()), filter(false)
{
    if (use_turn_restrictions)
    {
        const unsigned count = restrictions.size();
        if (count > 0)
        {
            util::Log() << "Found " << count << " turn restriction tags:";
            for (const std::string &str : restrictions)
            {
                util::Log() << "  " << str;
            }
        }
        else
        {
            util::Log() << "Found no turn restriction tags";
        }
    }

    filter.add(true, "restriction");
    if (parse_conditionals)
    {
        filter.add(true, "restriction:conditional");
        for (const auto &namespaced : restrictions_)
        {
            filter.add(true, "restriction:" + namespaced + ":conditional");
        }
    }

    // Not only use restriction= but also e.g. restriction:motorcar=
    // Include restriction:{mode}:conditional if flagged
    for (const auto &namespaced : restrictions_)
    {
        filter.add(true, "restriction:" + namespaced);
    }
}

/**
 * Tries to parse a relation as a turn restriction. This can fail for a number of
 * reasons. The return type is a std::vector<T>.
 *
 * Some restrictions can also be ignored: See the ```get_restrictions``` function
 * in the corresponding profile. We use it for both namespacing restrictions, as in
 * restriction:motorcar as well as whitelisting if its in except:motorcar.
 */
std::vector<InputTurnRestriction>
RestrictionParser::TryParse(const osmium::Relation &relation) const
{
    // return if turn restrictions should be ignored
    if (!use_turn_restrictions)
    {
        return {};
    }

    const osmium::TagList &tag_list = relation.tags();

    osmium::tags::KeyFilter::iterator fi_begin(filter, tag_list.begin(), tag_list.end());
    osmium::tags::KeyFilter::iterator fi_end(filter, tag_list.end(), tag_list.end());

    // if it's not a restriction, continue;
    if (fi_begin == fi_end)
    {
        return {};
    }

    // check if the restriction should be ignored
    const char *except = relation.get_value_by_key("except");
    if (except != nullptr && ShouldIgnoreRestriction(except))
    {
        return {};
    }

    bool is_only_restriction = false;
    bool is_multi_from = false;
    bool is_multi_to = false;

    std::vector<util::OpeningHours> condition;

    for (; fi_begin != fi_end; ++fi_begin)
    {
        auto value = fi_begin->value();

        // documented OSM restriction tags start either with only_* or no_*;
        // check and return on these values, and ignore no_*_on_red or unrecognized values
        if (boost::algorithm::starts_with(value, "only_"))
        {
            is_only_restriction = true;
        }
        else if (boost::algorithm::starts_with(value, "no_") &&
                 !boost::algorithm::ends_with(value, "_on_red"))
        {
            is_only_restriction = false;
            if (boost::algorithm::starts_with(value, "no_exit"))
            {
                is_multi_to = true;
            }
            else if (boost::algorithm::starts_with(value, "no_entry"))
            {
                is_multi_from = true;
            }
        }
        else // unrecognized value type
        {
            return {};
        }

        if (parse_conditionals)
        {
            // Parse condition and add independent value/condition pairs
            const auto &parsed = osrm::util::ParseConditionalRestrictions(value);

            if (parsed.empty())
                continue;

            for (const auto &p : parsed)
            {
                std::vector<util::OpeningHours> hours = util::ParseOpeningHours(p.condition);
                // found unrecognized condition, continue
                if (hours.empty())
                    return {};

                condition = std::move(hours);
            }
        }
    }

    constexpr auto INVALID_OSM_ID = std::numeric_limits<std::uint64_t>::max();
    std::vector<OSMWayID> from_ways;
    auto via_node = INVALID_OSM_ID;
    std::vector<OSMWayID> via_ways;
    std::vector<OSMWayID> to_ways;
    bool is_node_restriction = true;

    for (const auto &member : relation.members())
    {
        const char *role = member.role();
        const bool is_from_role = strcmp("from", role) == 0;
        const bool is_to_role = strcmp("to", role) == 0;
        const bool is_via_role = strcmp("via", role) == 0;

        if (!is_from_role && !is_to_role && !is_via_role)
        {
            continue;
        }

        switch (member.type())
        {
        case osmium::item_type::node:
        {

            // Make sure nodes appear only in the role if a via node
            if (is_from_role || is_to_role)
            {
                continue;
            }
            BOOST_ASSERT(is_via_role);
            via_node = static_cast<std::uint64_t>(member.ref());
            is_node_restriction = true;
            // set via node id
            break;
        }
        case osmium::item_type::way:
            BOOST_ASSERT(is_from_role || is_to_role || is_via_role);
            if (is_from_role)
            {
                from_ways.push_back({static_cast<std::uint64_t>(member.ref())});
            }
            else if (is_to_role)
            {
                to_ways.push_back({static_cast<std::uint64_t>(member.ref())});
            }
            else if (is_via_role)
            {
                via_ways.push_back({static_cast<std::uint64_t>(member.ref())});
                is_node_restriction = false;
            }
            break;
        case osmium::item_type::relation:
            // not yet supported, but who knows what the future holds...
            break;
        default:
            // shouldn't ever happen
            break;
        }
    }

    std::vector<InputTurnRestriction> restriction_containers;
    if (!from_ways.empty() && (via_node != INVALID_OSM_ID || !via_ways.empty()) && !to_ways.empty())
    {
        if (from_ways.size() > 1 && !is_multi_from)
        {
            util::Log(logDEBUG) << "Parsed restriction " << relation.id()
                                << " unexpectedly contains " << from_ways.size()
                                << " from ways, skipping...";
            return {};
        }
        if (to_ways.size() > 1 && !is_multi_to)
        {
            util::Log(logDEBUG) << "Parsed restriction " << relation.id()
                                << " unexpectedly contains " << to_ways.size()
                                << " to ways, skipping...";
            return {};
        }
        // Internally restrictions are represented with one 'from' and one 'to' way.
        // Therefore, we need to convert a multi from/to restriction into multiple restrictions.
        for (const auto &from : from_ways)
        {
            for (const auto &to : to_ways)
            {
                InputTurnRestriction restriction;
                restriction.is_only = is_only_restriction;
                restriction.condition = condition;
                if (is_node_restriction)
                {
                    // template struct requires bracket for ID initialisation :(
                    restriction.turn_path.node_or_way = InputViaNodePath{{from}, {via_node}, {to}};
                }
                else
                {
                    // template struct requires bracket for ID initialisation :(
                    restriction.turn_path.node_or_way = InputViaWayPath{{from}, via_ways, {to}};
                }
                restriction_containers.push_back(std::move(restriction));
            }
        }
    }
    return restriction_containers;
}

bool RestrictionParser::ShouldIgnoreRestriction(const std::string &except_tag_string) const
{
    // should this restriction be ignored? yes if there's an overlap between:
    // a) the list of modes in the except tag of the restriction
    //    (except_tag_string), eg: except=bus;bicycle
    // b) the lua profile defines a hierarchy of modes,
    //    eg: [access, vehicle, bicycle]

    if (except_tag_string.empty())
    {
        return false;
    }

    // split `except_tag_string` by semicolon and check if any of items is in `restrictions`
    std::string current_string;
    for (auto index : util::irange<size_t>(0, except_tag_string.size()))
    {
        const auto ch = except_tag_string[index];
        if (ch != ';')
        {
            current_string += ch;
        }
        else
        {
            if (restrictions.find(current_string) != restrictions.end())
            {
                return true;
            }
            current_string.clear();
        }
    }
    return restrictions.find(current_string) != restrictions.end();
}
} // namespace osrm::extractor