redis/detail/reader_fsm.hpp

0001 /* Copyright (c) 2018-2025 Marcelo Zimbres Silva (mzimbres@gmail.com)
0002  *
0003  * Distributed under the Boost Software License, Version 1.0. (See
0004  * accompanying file LICENSE.txt)
0005  */
0006
0007 #ifndef BOOST_REDIS_READER_FSM_HPP
0008 #define BOOST_REDIS_READER_FSM_HPP
0009
0010 #include <boost/redis/detail/connection_state.hpp>
0011 #include <boost/redis/detail/multiplexer.hpp>
0012
0013 #include <boost/asio/cancellation_type.hpp>
0014 #include <boost/system/error_code.hpp>
0015
0016 #include <chrono>
0017 #include <cstddef>
0018
0019 namespace boost::redis::detail {
0020
0021 class read_buffer;
0022
0023 class reader_fsm {
0024 public:
0025    class action {
0026    public:
0027       enum class type
0028       {
0029          read_some,
0030          notify_push_receiver,
0031          done,
0032       };
0033
0034       action(system::error_code ec) noexcept
0035       : type_(type::done)
0036       , ec_(ec)
0037       { }
0038
0039       static action read_some(std::chrono::steady_clock::duration timeout) { return {timeout}; }
0040
0041       static action notify_push_receiver(std::size_t bytes) { return {bytes}; }
0042
0043       type get_type() const { return type_; }
0044
0045       system::error_code error() const
0046       {
0047          BOOST_ASSERT(type_ == type::done);
0048          return ec_;
0049       }
0050
0051       std::chrono::steady_clock::duration timeout() const
0052       {
0053          BOOST_ASSERT(type_ == type::read_some);
0054          return timeout_;
0055       }
0056
0057       std::size_t push_size() const
0058       {
0059          BOOST_ASSERT(type_ == type::notify_push_receiver);
0060          return push_size_;
0061       }
0062
0063    private:
0064       action(std::size_t push_size) noexcept
0065       : type_(type::notify_push_receiver)
0066       , push_size_(push_size)
0067       { }
0068
0069       action(std::chrono::steady_clock::duration t) noexcept
0070       : type_(type::read_some)
0071       , timeout_(t)
0072       { }
0073
0074       type type_;
0075       union {
0076          system::error_code ec_;
0077          std::chrono::steady_clock::duration timeout_;
0078          std::size_t push_size_{};
0079       };
0080    };
0081
0082    action resume(
0083       connection_state& st,
0084       std::size_t bytes_read,
0085       system::error_code ec,
0086       asio::cancellation_type_t cancel_state);
0087
0088    reader_fsm() = default;
0089
0090 private:
0091    int resume_point_{0};
0092    std::pair<consume_result, std::size_t> res_{consume_result::needs_more, 0u};
0093 };
0094
0095 }  // namespace boost::redis::detail
0096
0097 #endif  // BOOST_REDIS_READER_FSM_HPP