v3_1_1_subscribe.hpp

// Copyright Takatoshi Kondo 2022
//
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
 
#if !defined(ASYNC_MQTT_PACKET_V3_1_1_SUBSCRIBE_HPP)
#define ASYNC_MQTT_PACKET_V3_1_1_SUBSCRIBE_HPP
 
#include <boost/numeric/conversion/cast.hpp>
 
#include <async_mqtt/exception.hpp>
#include <async_mqtt/buffer.hpp>
 
#include <async_mqtt/util/move.hpp>
#include <async_mqtt/util/static_vector.hpp>
#include <async_mqtt/util/endian_convert.hpp>
#include <async_mqtt/util/utf8validate.hpp>
 
#include <async_mqtt/packet/packet_id_type.hpp>
#include <async_mqtt/packet/fixed_header.hpp>
#include <async_mqtt/packet/topic_subopts.hpp>
#include <async_mqtt/variable_bytes.hpp>
#include <async_mqtt/packet/copy_to_static_vector.hpp>
 
namespace async_mqtt::v3_1_1 {
 
namespace as = boost::asio;
 
template <std::size_t PacketIdBytes>
class basic_subscribe_packet {
public:
    using packet_id_t = typename packet_id_type<PacketIdBytes>::type;
 
    basic_subscribe_packet(
        packet_id_t packet_id,
        std::vector<topic_subopts> params
    )
        : fixed_header_{make_fixed_header(control_packet_type::subscribe, 0b0010)},
          entries_{force_move(params)},
          remaining_length_{PacketIdBytes}
    {
        topic_length_buf_entries_.reserve(entries_.size());
        for (auto const& e : entries_) {
            topic_length_buf_entries_.push_back(
                endian_static_vector(
                    boost::numeric_cast<std::uint16_t>(e.all_topic().size())
                )
            );
        }
 
        endian_store(packet_id, packet_id_.data());
 
        for (auto const& e : entries_) {
            // reserved bits check
            if (static_cast<std::uint8_t>(e.opts()) & 0b11111100) {
                throw make_error(
                    errc::bad_message,
                    "v3_1_1::subscribe_packet subopts is invalid"
                );
            }
            switch (e.opts().get_qos()) {
            case qos::at_most_once:
            case qos::at_least_once:
            case qos::exactly_once:
                break;
            default:
                throw make_error(
                    errc::bad_message,
                    "v3_1_1::subscribe_packet qos is invalid"
                );
                break;
            }
 
            auto size = e.all_topic().size();
            if (size > 0xffff) {
                throw make_error(
                    errc::bad_message,
                    "v3_1_1::subscribe_packet length of topic is invalid"
                );
            }
            remaining_length_ +=
                2 +                     // topic filter length
                size +                  // topic filter
                1;                      // opts
 
            if (!utf8string_check(e.all_topic())) {
                throw make_error(
                    errc::bad_message,
                    "v3_1_1::subscribe_packet topic filter invalid utf8"
                );
            }
        }
 
        remaining_length_buf_ = val_to_variable_bytes(boost::numeric_cast<std::uint32_t>(remaining_length_));
    }
 
    basic_subscribe_packet(buffer buf) {
        // fixed_header
        if (buf.empty()) {
            throw make_error(
                errc::bad_message,
                "v3_1_1::subscribe_packet fixed_header doesn't exist"
            );
        }
        fixed_header_ = static_cast<std::uint8_t>(buf.front());
        buf.remove_prefix(1);
        auto cpt_opt = get_control_packet_type_with_check(static_cast<std::uint8_t>(fixed_header_));
        if (!cpt_opt || *cpt_opt != control_packet_type::subscribe) {
            throw make_error(
                errc::bad_message,
                "v3_1_1::subscribe_packet fixed_header is invalid"
            );
        }
 
        // remaining_length
        if (auto vl_opt = insert_advance_variable_length(buf, remaining_length_buf_)) {
            remaining_length_ = *vl_opt;
        }
        else {
            throw make_error(errc::bad_message, "v3_1_1::subscribe_packet remaining length is invalid");
        }
        if (remaining_length_ != buf.size()) {
            throw make_error(errc::bad_message, "v3_1_1::subscribe_packet remaining length doesn't match buf.size()");
        }
 
        // packet_id
        if (!copy_advance(buf, packet_id_)) {
            throw make_error(
                errc::bad_message,
                "v3_1_1::subscribe_packet packet_id doesn't exist"
            );
        }
 
        if (remaining_length_ == 0) {
            throw make_error(errc::bad_message, "v3_1_1::subscribe_packet doesn't have entries");
        }
 
        while (!buf.empty()) {
            // topic_length
            static_vector<char, 2> topic_length_buf;
            if (!insert_advance(buf, topic_length_buf)) {
                throw make_error(
                    errc::bad_message,
                    "v3_1_1::subscribe_packet length of topic is invalid"
                );
            }
            auto topic_length = endian_load<std::uint16_t>(topic_length_buf.data());
            topic_length_buf_entries_.push_back(topic_length_buf);
 
            // topic
            if (buf.size() < topic_length) {
                throw make_error(
                    errc::bad_message,
                    "v3_1_1::subscribe_packet topic doesn't match its length"
                );
            }
            auto topic = buf.substr(0, topic_length);
 
            if (!utf8string_check(topic)) {
                throw make_error(
                    errc::bad_message,
                    "v3_1_1::subscribe_packet topic filter invalid utf8"
                );
            }
 
            buf.remove_prefix(topic_length);
 
            // opts
            if (buf.empty()) {
                throw make_error(
                    errc::bad_message,
                    "v3_1_1::subscribe_packet subscribe options  doesn't exist"
                );
            }
            auto opts = static_cast<sub::opts>(std::uint8_t(buf.front()));
            if (static_cast<std::uint8_t>(opts) & 0b11111100) {
                throw make_error(
                    errc::bad_message,
                    "v3_1_1::subscribe_packet subopts is invalid"
                );
            }
            switch (opts.get_qos()) {
            case qos::at_most_once:
            case qos::at_least_once:
            case qos::exactly_once:
                break;
            default:
                throw make_error(
                    errc::bad_message,
                    "v3_1_1::subscribe_packet qos is invalid"
                );
                break;
            }
            entries_.emplace_back(force_move(topic), opts);
            buf.remove_prefix(1);
        }
    }
 
    constexpr control_packet_type type() const {
        return control_packet_type::subscribe;
    }
 
    std::vector<as::const_buffer> const_buffer_sequence() const {
        std::vector<as::const_buffer> ret;
        ret.reserve(num_of_const_buffer_sequence());
 
        ret.emplace_back(as::buffer(&fixed_header_, 1));
 
        ret.emplace_back(as::buffer(remaining_length_buf_.data(), remaining_length_buf_.size()));
 
        ret.emplace_back(as::buffer(packet_id_.data(), packet_id_.size()));
 
        BOOST_ASSERT(entries_.size() == topic_length_buf_entries_.size());
        auto it = topic_length_buf_entries_.begin();
        for (auto const& e : entries_) {
            ret.emplace_back(as::buffer(it->data(), it->size()));
            ret.emplace_back(as::buffer(e.all_topic()));
            ret.emplace_back(as::buffer(&e.opts(), 1));
            ++it;
        }
 
        return ret;
    }
 
    std::size_t size() const {
        return
            1 +                            // fixed header
            remaining_length_buf_.size() +
            remaining_length_;
    }
 
    std::size_t num_of_const_buffer_sequence() const {
        return
            1 +                   // fixed header
            1 +                   // remaining length
            1 +                   // packet id
            entries_.size() * 3;  // topic name length, topic name, qos
    }
 
    packet_id_t packet_id() const {
        return endian_load<packet_id_t>(packet_id_.data());
    }
 
    std::vector<topic_subopts> const& entries() const {
        return entries_;
    }
 
private:
    std::uint8_t fixed_header_;
    std::vector<static_vector<char, 2>> topic_length_buf_entries_;
    std::vector<topic_subopts> entries_;
    static_vector<char, PacketIdBytes> packet_id_ = static_vector<char, PacketIdBytes>(PacketIdBytes);
    std::size_t remaining_length_;
    static_vector<char, 4> remaining_length_buf_;
};
 
template <std::size_t PacketIdBytes>
inline std::ostream& operator<<(std::ostream& o, basic_subscribe_packet<PacketIdBytes> const& v) {
    o <<
        "v3_1_1::subscribe{" <<
        "pid:" << v.packet_id() << ",[";
    auto b = v.entries().cbegin();
    auto e = v.entries().cend();
    if (b != e) {
        o <<
            "{topic:" <<
            b->all_topic() << "," <<
            "qos:" << b->opts().get_qos() << "}";
        ++b;
    }
    for (; b != e; ++b) {
        o << "," <<
            "{topic:" <<
            b->all_topic() << "," <<
            "qos:" << b->opts().get_qos() << "}";
    }
    o << "]}";
    return o;
}
 
using subscribe_packet = basic_subscribe_packet<2>;
 
} // namespace async_mqtt::v3_1_1
 
#endif // ASYNC_MQTT_PACKET_V3_1_1_SUBSCRIBE_HPP