frame.hpp

/* -*- mode: c++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * Copyright (C) 2025 Marco Craveiro <marco.craveiro@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 3 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */
#ifndef ORES_COMMS_MESSAGING_FRAME_HPP
#define ORES_COMMS_MESSAGING_FRAME_HPP
 
#include <span>
#include <array>
#include <vector>
#include <iosfwd>
#include <cstdint>
#include <expected>
#include "ores.utility/log/make_logger.hpp"
#include "ores.comms/messaging/message_types.hpp"
 
namespace ores::comms::messaging {
 
constexpr size_t MAX_PAYLOAD_SIZE = 1'000'000;
 
struct frame_header final {
    std::uint32_t magic;
    std::uint16_t version_major;
    std::uint16_t version_minor;
    message_type type;
    compression_type compression;
    std::uint8_t compression_flags;
    std::uint32_t payload_size;
    std::uint32_t sequence;
    std::uint32_t crc;
    std::uint32_t correlation_id;
    std::array<std::uint8_t, 4> reserved2;
 
    static constexpr size_t size = 32;
};
 
class frame final {
private:
    inline static std::string_view logger_name = "ores.comms.messaging.frame";
 
    static auto& lg() {
        using namespace ores::utility::log;
        static auto instance = make_logger(logger_name);
        return instance;
    }
 
public:
    frame();
    frame(message_type type, std::uint32_t sequence, std::vector<std::byte> payload,
        compression_type compression = compression_type::none);
    frame(message_type type, std::uint32_t sequence, std::uint32_t correlation_id,
        std::vector<std::byte> payload,
        compression_type compression = compression_type::none);
 
    std::uint32_t correlation_id() const { return header_.correlation_id; }
 
    const frame_header& header() const { return header_; }
 
    const std::vector<std::byte>& payload() const { return payload_; }
 
    compression_type compression() const { return header_.compression; }
 
    std::expected<std::vector<std::byte>, error_code> decompressed_payload() const;
 
    std::vector<std::byte> serialize() const;
 
    static std::expected<frame_header, error_code> deserialize_header(
        std::span<const std::byte> data, bool skip_version_check = false);
 
    static std::expected<frame, error_code>
    deserialize(const frame_header& header, std::span<const std::byte> data);
 
    std::expected<void, error_code> validate() const;
 
private:
    frame_header header_;
    std::vector<std::byte> payload_;
 
    std::uint32_t calculate_crc() const;
 
    void serialize_header(frame_header header, std::span<std::byte> buffer) const;
 
    void init_payload(std::vector<std::byte> payload, compression_type compression);
};
 
std::ostream& operator<<(std::ostream& s, const frame_header& v);
 
}
 
#endif