pre-eventpp snapshot

CMakeLists.txt

@@ -20,5 +20,5 @@ FetchContent_Declare(
 )
 FetchContent_MakeAvailable(tomlplusplus)
 
-add_executable(xbot main.cpp ircmsg.cpp settings.cpp connection.cpp)
+add_executable(xbot main.cpp ircmsg.cpp settings.cpp connection.cpp thread.cpp watchdog_thread.cpp irc_parse_thread.cpp write_irc.cpp ping_thread.cpp registration_thread.cpp)
 target_link_libraries(xbot PRIVATE Boost::headers OpenSSL::SSL tomlplusplus_tomlplusplus)

connection.cpp

@@ -1,5 +1,21 @@
 #include "connection.hpp"
 
+Connection::Connection(boost::asio::io_context & io)
+: stream_{io}
+, write_timer_{io, std::chrono::steady_clock::time_point::max()}
+{
+}
+
+auto Connection::add_thread(std::shared_ptr<Thread> thread) -> void
+{
+    dispatcher_.add_thread(std::move(thread));
+}
+
+auto Connection::add_event(std::shared_ptr<Event> event) -> void
+{
+    dispatcher_.dispatch(std::move(event));
+}
+
 auto Connection::writer_() -> void
 {
     std::vector<boost::asio::const_buffer> buffers;
@@ -48,20 +64,24 @@ auto Connection::writer() -> void
 
 auto Connection::connect(
     boost::asio::io_context & io,
-    Settings settings)
--> boost::asio::awaitable<void>
+    std::string host,
+    std::string port
+) -> boost::asio::awaitable<void>
 {
-    auto self = shared_from_this();
+    using namespace std::placeholders;
+
+    // keep connection alive while coroutine is active
+    auto const self = shared_from_this();
 
     {
         auto resolver = boost::asio::ip::tcp::resolver{io};
-        auto const endpoints = co_await resolver.async_resolve(settings.host, settings.service, boost::asio::use_awaitable);
+        auto const endpoints = co_await resolver.async_resolve(host, port, boost::asio::use_awaitable);
         auto const endpoint = co_await boost::asio::async_connect(stream_, endpoints, boost::asio::use_awaitable);
 
-        self->writer();
-        dispatch(&IrcThread::on_connect);
+        make_event<ConnectEvent>();
     }
 
+    self->writer();
     for(LineBuffer buffer{32'768};;)
     {
         boost::system::error_code error;
@@ -71,38 +91,25 @@ auto Connection::connect(
             break;
         }
         buffer.add_bytes(n, [this](char * line) {
-            dispatch<ircmsg const&>(&IrcThread::on_msg, parse_irc_message(line));
+            make_event<LineEvent>(line);
         });
     }
 
-    dispatch(&IrcThread::on_disconnect);
+    make_event<DisconnectEvent>();
 }
 
-auto Connection::write(std::string message) -> void
+auto Connection::write_raw(std::string message) -> void
 {
+    std::cout << "Writing " << message;
     auto const need_cancel = write_strings_.empty();
-
-    message += "\r\n";
     write_strings_.push_back(std::move(message));
-
     if (need_cancel)
     {
         write_timer_.cancel_one();
     }
 }
 
-auto Connection::write(std::string front, std::string_view last) -> void
-    {
-        auto const is_invalid = [](char x) -> bool {
-            return x == '\0' || x == '\r' || x == '\n';
-        };
-
-        if (last.end() != std::find_if(last.begin(), last.end(), is_invalid))
-        {
-            throw std::runtime_error{"bad irc argument"};
-        }
-
-        front += " :";
-        front += last;
-        write(std::move(front));
-    }
+auto Connection::close() -> void
+{
+    stream_.close();
+}

connection.hpp

@@ -1,14 +1,13 @@
 #pragma once
 
-#include "irc_thread.hpp"
-#include "ircmsg.hpp"
 #include "linebuffer.hpp"
 #include "settings.hpp"
+#include "thread.hpp"
 
 #include <boost/asio.hpp>
 
 #include <chrono>
-#include <coroutine>
+#include <concepts>
 #include <iostream>
 #include <list>
 #include <memory>
@@ -19,79 +18,49 @@
 #include <variant>
 #include <vector>
 
+struct ConnectEvent : Event
+{
+};
+
+struct DisconnectEvent : Event
+{
+};
+
+struct LineEvent : Event
+{
+    explicit LineEvent(char * line) : line{line} {}
+    char * line;
+};
+
 class Connection : public std::enable_shared_from_this<Connection>
 {
     boost::asio::ip::tcp::socket stream_;
     boost::asio::steady_timer write_timer_;
-
     std::list<std::string> write_strings_;
-    std::vector<std::unique_ptr<IrcThread>> threads_;
+    Dispatcher dispatcher_;
 
     auto writer() -> void;
     auto writer_() -> void;
 
-    template <typename... Args>
-    auto dispatch(
-        IrcThread::callback_result (IrcThread::* method)(Args...),
-        Args... args
-    ) -> void
-    {
-        std::vector<std::unique_ptr<IrcThread>> work;
-        work.swap(threads_);
-        std::sort(work.begin(), work.end(), [](auto const& a, auto const& b) { return a->priority() < b->priority(); });
-
-        std::size_t const n = work.size();
-        for (std::size_t i = 0; i < n; i++)
-        {
-            auto const [thread_outcome, msg_outcome] = (work[i].get()->*method)(args...);
-            if (thread_outcome == ThreadOutcome::Continue)
-            {
-                threads_.push_back(std::move(work[i]));
-            }
-            if (msg_outcome == EventOutcome::Consume)
-            {
-                std::move(work.begin() + i + 1, work.end(), std::back_inserter(threads_));
-                break;
-            }
-        }
-    }
-
 public:
-    Connection(boost::asio::io_context & io)
-    : stream_{io}
-    , write_timer_{io, std::chrono::steady_clock::time_point::max()}
-    {
+    Connection(boost::asio::io_context & io);
+    auto add_thread(std::shared_ptr<Thread> thread) -> void;
+    auto add_event(std::shared_ptr<Event> event) -> void;
+
+    template <typename T, typename... Args>
+    auto make_event(Args&& ... args) {
+        add_event(std::make_shared<T>(std::forward<Args>(args)...));
     }
 
-    auto listen(std::unique_ptr<IrcThread> thread) -> void
-    {
-        threads_.push_back(std::move(thread));
-    }
-
-    auto write(std::string front, std::string_view last) -> void;
-
-    template <typename... Args>
-    auto write(std::string front, std::string_view next, Args ...rest) -> void
-    {
-        auto const is_invalid = [](char x) -> bool {
-            return x == '\0' || x == '\r' || x == '\n' || x == ' ';
-        };
-
-        if (next.empty() || next.end() != std::find_if(next.begin(), next.end(), is_invalid))
-        {
-            throw std::runtime_error{"bad irc argument"};
-        }
-
-        front += " ";
-        front += next;
-        write(std::move(front), rest...);
-    }
-
-    auto write(std::string message) -> void;
+    /// Write bytes into the socket. Messages should be properly newline terminated.
+    auto write_raw(std::string message) -> void;
 
     auto connect(
         boost::asio::io_context & io,
-        Settings settings
+        std::string host,
+        std::string port
     ) -> boost::asio::awaitable<void>;
+
+    auto close() -> void;
 };
 

irc_parse_thread.cpp

@@ -0,0 +1,21 @@
+#include "irc_parse_thread.hpp"
+
+#include "connection.hpp"
+
+IrcParseThread::IrcParseThread(Connection * connection) noexcept
+: connection_{connection} {}
+
+auto IrcParseThread::priority() const -> priority_type
+{
+    return 0;
+}
+
+auto IrcParseThread::on_event(Event const& event) -> callback_result
+{
+    if (auto line_event = dynamic_cast<LineEvent const*>(&event))
+    {
+        connection_->make_event<IrcMsgEvent>(parse_irc_message(line_event->line));
+        return { ThreadOutcome::Continue, EventOutcome::Consume };
+    }
+    return {};
+}

irc_parse_thread.hpp

@@ -0,0 +1,20 @@
+#pragma once
+
+#include "thread.hpp"
+
+class Connection;
+
+struct IrcMsgEvent : Event
+{
+    IrcMsgEvent(IrcMsg irc) : irc{irc} {}
+    IrcMsg irc;
+};
+
+struct IrcParseThread : Thread
+{
+    Connection * connection_;
+
+    IrcParseThread(Connection * connection) noexcept;
+    auto priority() const -> priority_type override;
+    auto on_event(Event const& event) -> callback_result override;
+};

irc_thread.hpp

@@ -1,27 +0,0 @@
-#pragma once
-
-#include "ircmsg.hpp"
-
-enum class EventOutcome
-{
-    Pass,
-    Consume,
-};
-
-enum class ThreadOutcome
-{
-    Continue,
-    Finish,
-};
-
-struct IrcThread
-{
-    using priority_type = std::uint64_t;
-    using callback_result = std::pair<ThreadOutcome, EventOutcome>;
-    virtual ~IrcThread() {}
-
-    virtual auto on_connect() -> callback_result { return {}; }
-    virtual auto on_disconnect() -> callback_result { return {}; };
-    virtual auto on_msg(ircmsg const&) -> callback_result { return {}; };
-    virtual auto priority() const -> priority_type = 0;
-};

ircmsg.cpp

@@ -4,7 +4,7 @@
 #include "ircmsg.hpp"
 
 namespace {
-class parser {
+class Parser {
     char* msg_;
     inline static char empty[1];
 
@@ -13,7 +13,7 @@ class parser {
     }
 
 public:
-    parser(char* msg) : msg_(msg) {
+    Parser(char* msg) : msg_(msg) {
         if (msg_ == nullptr) {
             msg_ = empty;
         } else {
@@ -101,10 +101,10 @@ auto parse_irc_tags(char* str) -> std::vector<irctag>
     return tags;
 }
 
-auto parse_irc_message(char* msg) -> ircmsg
+auto parse_irc_message(char* msg) -> IrcMsg
 {
-    parser p {msg};
-    ircmsg out;
+    Parser p {msg};
+    IrcMsg out;
 
     /* MESSAGE TAGS */
     if (p.match('@')) {
@@ -134,7 +134,7 @@ auto parse_irc_message(char* msg) -> ircmsg
     return out;
 }
 
-auto ircmsg::hassource() const -> bool
+auto IrcMsg::hassource() const -> bool
 {
     return source.data() != nullptr;
 }

ircmsg.hpp

@@ -14,16 +14,16 @@ struct irctag
     friend auto operator==(irctag const&, irctag const&) -> bool = default;
 };
 
-struct ircmsg
+struct IrcMsg
 {
     std::vector<irctag> tags;
     std::vector<std::string_view> args;
     std::string_view source;
     std::string_view command;
 
-    ircmsg() = default;
+    IrcMsg() = default;
 
-    ircmsg(
+    IrcMsg(
         std::vector<irctag> && tags,
         std::string_view source,
         std::string_view command,
@@ -35,7 +35,7 @@ struct ircmsg
 
       bool hassource() const;
 
-      friend bool operator==(ircmsg const&, ircmsg const&) = default;
+      friend bool operator==(IrcMsg const&, IrcMsg const&) = default;
 };
 
 enum class irc_error_code {
@@ -57,6 +57,6 @@ struct irc_parse_error : public std::exception {
  *
  * Returns zero for success, non-zero for parse error.
  */
-auto parse_irc_message(char* msg) -> ircmsg;
+auto parse_irc_message(char* msg) -> IrcMsg;
 
 auto parse_irc_tags(char* msg) -> std::vector<irctag>;

main.cpp

@@ -1,11 +1,15 @@
 #include <boost/asio.hpp>
 #include <boost/asio/ssl.hpp>
 
-#include "linebuffer.hpp"
-#include "ircmsg.hpp"
-#include "settings.hpp"
-#include "irc_thread.hpp"
 #include "connection.hpp"
+#include "ircmsg.hpp"
+#include "linebuffer.hpp"
+#include "settings.hpp"
+#include "thread.hpp"
+
+#include "irc_parse_thread.hpp"
+#include "ping_thread.hpp"
+#include "registration_thread.hpp"
 
 #include <algorithm>
 #include <chrono>
@@ -27,234 +31,47 @@
 using namespace std::chrono_literals;
 
 
-struct ChatThread : public IrcThread
+struct ChatThread : public Thread
 {
     auto priority() const -> priority_type override
     {
         return 100;
     }
-    auto on_msg(ircmsg const& irc) -> std::pair<ThreadOutcome, EventOutcome> override
+    auto on_event(Event const& event) -> callback_result override
     {
-        if (irc.command == "PRIVMSG" && 2 == irc.args.size())
+        if (auto const* irc_event = dynamic_cast<IrcMsgEvent const*>(&event))
         {
-            std::cout << "Chat from " << irc.source << ": " << irc.args[1] << std::endl;
-            return {ThreadOutcome::Continue, EventOutcome::Pass};
+            auto const& irc = irc_event->irc;
+            if (irc.command == "PRIVMSG" && 2 == irc.args.size())
+            {
+                std::cout << "Chat from " << irc.source << ": " << irc.args[1] << std::endl;
+                return { ThreadOutcome::Continue, EventOutcome::Consume };
+            }
         }
-        else
-        {
-            return {ThreadOutcome::Continue, EventOutcome::Pass};
-        }
-    }
-};
-
-struct UnhandledThread : public IrcThread
-{
-    auto priority() const -> priority_type override
-    {
-        return std::numeric_limits<IrcThread::priority_type>::max();
-    }
-
-    auto on_msg(ircmsg const& irc) -> std::pair<ThreadOutcome, EventOutcome> override
-    {
-        std::cout << "Unhandled message " << irc.command;
-        for (auto const arg : irc.args)
-        {
-            std::cout << " " << arg;
-        }
-        std::cout << "\n";
-        return {ThreadOutcome::Continue, EventOutcome::Pass};
-    }
-};
-
-class PingThread : public IrcThread
-{
-    Connection * connection_;
-
-public:
-    PingThread(Connection * connection) noexcept : connection_{connection} {}
-
-    auto priority() const -> priority_type override
-    {
-        return 0;
-    }
-
-    auto on_msg(ircmsg const& irc) -> std::pair<ThreadOutcome, EventOutcome> override
-    {
-        if (irc.command == "PING" && 1 == irc.args.size())
-        {
-            connection_->write("PONG", irc.args[0]);
-            return {ThreadOutcome::Continue, EventOutcome::Consume};
-        }
-        else
-        {
-            return {};
-        }
-    }
-};
-
-struct RegistrationThread : IrcThread
-{
-    Connection * connection_;
-    std::string password_;
-    std::string username_;
-    std::string realname_;
-    std::string nickname_;
-
-    std::unordered_map<std::string, std::string> caps;
-    std::unordered_set<std::string> outstanding;
-
-    enum class Stage
-    {
-        LsReply,
-        AckReply,
-    };
-
-    Stage stage_;
-
-    RegistrationThread(
-        Connection * connection_,
-        std::string password,
-        std::string username,
-        std::string realname,
-        std::string nickname
-    )
-    : connection_{connection_}
-    , password_{password}
-    , username_{username}
-    , realname_{realname}
-    , nickname_{nickname}
-    , stage_{Stage::LsReply}
-    {}
-
-    auto priority() const -> priority_type override { return 1; }
-    auto on_connect() -> IrcThread::callback_result override
-    {
-        connection_->write("CAP", "LS", "302");
-        connection_->write("PASS", password_);
-        connection_->write("USER", username_, "*", "*", realname_);
-        connection_->write("NICK", nickname_);
         return {};
     }
+};
 
-    auto send_req() -> IrcThread::callback_result
+struct UnhandledThread : public Thread
+{
+    auto priority() const -> priority_type override
     {
-        std::string request;
-        char const* want[] = { "extended-join", "account-notify", "draft/chathistory", "batch", "soju.im/no-implicit-names", "chghost", "setname", "account-tag", "solanum.chat/oper", "solanum.chat/identify-msg", "solanum.chat/realhost", "server-time", "invite-notify", "extended-join" };
-        for (auto cap : want)
-        {
-            if (caps.contains(cap))
-            {
-                request.append(cap);
-                request.push_back(' ');
-                outstanding.insert(cap);
-            }
-        }
-        if (not outstanding.empty())
-        {
-            request.pop_back();
-            connection_->write("CAP", "REQ", request);
-            stage_ = Stage::AckReply;
-            return {ThreadOutcome::Continue, EventOutcome::Consume};
-        }
-        else
-        {
-            connection_->write("CAP", "END");
-            return {ThreadOutcome::Finish, EventOutcome::Consume};
-        }
+        return std::numeric_limits<Thread::priority_type>::max();
     }
 
-    auto capack(ircmsg const& msg) -> IrcThread::callback_result
+    auto on_event(Event const& event) -> callback_result override
     {
-        auto const n = msg.args.size();
-        if ("CAP" == msg.command && n >= 2 && "*" == msg.args[0] && "ACK" == msg.args[1])
+        if (auto irc_event = dynamic_cast<IrcMsgEvent const*>(&event))
         {
-            auto in = std::istringstream{std::string{msg.args[2]}};
-            std::for_each(
-                std::istream_iterator<std::string>{in},
-                std::istream_iterator<std::string>{},
-                [this](std::string x) {
-                    outstanding.erase(x);
-                }
-            );
-            if (outstanding.empty())
+            auto& irc = irc_event->irc;
+            std::cout << "Unhandled message " << irc.command;
+            for (auto const arg : irc.args)
             {
-                connection_->write("CAP","END");
-                return {ThreadOutcome::Finish, EventOutcome::Consume};
-            }
-            else
-            {
-                return {ThreadOutcome::Continue, EventOutcome::Consume};
+                std::cout << " " << arg;
             }
+            std::cout << "\n";
         }
-        else
-        {
-            return {};
-        }
-    }
-
-    auto capls(ircmsg const& msg) -> IrcThread::callback_result
-    {
-        auto const n = msg.args.size();
-        if ("CAP" == msg.command && n >= 2 && "*" == msg.args[0] && "LS" == msg.args[1])
-        {
-            std::string_view const* kvs;
-            bool last;
-
-            if (3 == n)
-            {
-                kvs = &msg.args[2];
-                last = true;
-            }
-            else if (4 == n && "*" == msg.args[2])
-            {
-                kvs = &msg.args[3];
-                last = false;
-            }
-            else
-            {
-                return {};
-            }
-
-            auto in = std::istringstream{std::string{*kvs}};
-
-            std::for_each(
-                std::istream_iterator<std::string>{in},
-                std::istream_iterator<std::string>{},
-                [this](std::string x) {
-                    auto const eq = x.find('=');
-                    if (eq == x.npos)
-                    {
-                        caps.emplace(x, std::string{});
-                    }
-                    else
-                    {
-                        caps.emplace(std::string{x, 0, eq}, std::string{x, eq+1, x.npos});
-                    }
-                }
-            );
-
-            if (last)
-            {
-                return send_req();
-            }
-
-            return {ThreadOutcome::Continue, EventOutcome::Consume};
-        }
-        else
-        {
-            return {};
-        }
-
-    }
-
-    auto on_msg(ircmsg const& msg) -> IrcThread::callback_result override
-    {
-        switch (stage_)
-        {
-            case Stage::LsReply: return capls(msg);
-            case Stage::AckReply: return capack(msg);
-            default: return {};
-        }
+        return {};
     }
 };
 
@@ -262,19 +79,20 @@ auto start(boost::asio::io_context & io, Settings const& settings) -> void
 {
     auto connection = std::make_shared<Connection>(io);
 
-    connection->listen(std::make_unique<PingThread>(connection.get()));
-    connection->listen(std::make_unique<RegistrationThread>(connection.get(), settings.password, settings.username, settings.realname, settings.nickname));
-    connection->listen(std::make_unique<ChatThread>());
-    connection->listen(std::make_unique<UnhandledThread>());
+    connection->add_thread(std::make_shared<IrcParseThread>(connection.get()));
+    connection->add_thread(std::make_shared<PingThread>(connection.get()));
+    connection->add_thread(std::make_shared<RegistrationThread>(connection.get(), settings.password, settings.username, settings.realname, settings.nickname));
+    connection->add_thread(std::make_shared<ChatThread>());
+    connection->add_thread(std::make_shared<UnhandledThread>());
 
     boost::asio::co_spawn(
         io,
-        connection->connect(io, settings),
+        connection->connect(io, settings.host, settings.service),
         [&io, &settings](std::exception_ptr e)
         {
-            auto timer = boost::asio::steady_timer{io};
-            timer.expires_from_now(5s);
-            timer.async_wait([&io, &settings](auto) {
+            auto timer = std::make_shared<boost::asio::steady_timer>(io);
+            timer->expires_from_now(5s);
+            timer->async_wait([&io, &settings, timer](auto) {
                 start(io, settings);
             });
         });

ping_thread.cpp

@@ -0,0 +1,25 @@
+#include "ping_thread.hpp"
+
+#include "irc_parse_thread.hpp"
+#include "write_irc.hpp"
+
+PingThread::PingThread(Connection * connection) noexcept : connection_{connection} {}
+
+auto PingThread::priority() const -> priority_type
+{
+    return 1;
+}
+
+auto PingThread::on_event(Event const& event) -> std::pair<ThreadOutcome, EventOutcome>
+{
+    if (auto const irc_event = dynamic_cast<IrcMsgEvent const*>(&event))
+    {
+        auto& irc = irc_event->irc;
+        if ("PING" == irc.command && 1 == irc.args.size())
+        {
+            write_irc(*connection_, "PONG", irc.args[0]);
+            return {ThreadOutcome::Continue, EventOutcome::Consume};
+        }
+    }
+    return {};
+}

ping_thread.hpp

@@ -0,0 +1,15 @@
+#pragma once
+
+#include "connection.hpp"
+#include "thread.hpp"
+
+class PingThread : public Thread
+{
+    Connection * connection_;
+
+public:
+    PingThread(Connection * connection) noexcept;
+
+    auto priority() const -> priority_type override;
+    auto on_event(Event const& event) -> std::pair<ThreadOutcome, EventOutcome> override;
+};

registration_thread.cpp

@@ -0,0 +1,164 @@
+#include "registration_thread.hpp"
+
+RegistrationThread::RegistrationThread(
+    Connection * connection_,
+    std::string password,
+    std::string username,
+    std::string realname,
+    std::string nickname
+)
+    : connection_{connection_}
+    , password_{password}
+    , username_{username}
+    , realname_{realname}
+    , nickname_{nickname}
+    , stage_{Stage::LsReply}
+{}
+
+auto RegistrationThread::priority() const -> priority_type
+{
+    return 2;
+}
+
+auto RegistrationThread::on_connect() -> Thread::callback_result
+{
+    write_irc(*connection_, "CAP", "LS", "302");
+    write_irc(*connection_, "PASS", password_);
+    write_irc(*connection_, "USER", username_, "*", "*", realname_);
+    write_irc(*connection_, "NICK", nickname_);
+    return {};
+}
+
+auto RegistrationThread::send_req() -> Thread::callback_result
+{
+    std::string request;
+    char const* want[] = { "extended-join", "account-notify", "draft/chathistory", "batch", "soju.im/no-implicit-names", "chghost", "setname", "account-tag", "solanum.chat/oper", "solanum.chat/identify-msg", "solanum.chat/realhost", "server-time", "invite-notify", "extended-join" };
+    for (auto cap : want)
+    {
+        if (caps.contains(cap))
+        {
+            request.append(cap);
+            request.push_back(' ');
+            outstanding.insert(cap);
+        }
+    }
+    if (not outstanding.empty())
+    {
+        request.pop_back();
+        write_irc(*connection_, "CAP", "REQ", request);
+        stage_ = Stage::AckReply;
+        return {ThreadOutcome::Continue, EventOutcome::Consume};
+    }
+    else
+    {
+        write_irc(*connection_, "CAP", "END");
+        return {ThreadOutcome::Finish, EventOutcome::Consume};
+    }
+}
+
+auto RegistrationThread::capack(IrcMsg const& msg) -> Thread::callback_result
+{
+    auto const n = msg.args.size();
+    if ("CAP" == msg.command && n >= 2 && "*" == msg.args[0] && "ACK" == msg.args[1])
+    {
+        auto in = std::istringstream{std::string{msg.args[2]}};
+        std::for_each(
+            std::istream_iterator<std::string>{in},
+            std::istream_iterator<std::string>{},
+            [this](std::string x) {
+                outstanding.erase(x);
+            }
+        );
+        if (outstanding.empty())
+        {
+            write_irc(*connection_, "CAP", "END");
+            return {ThreadOutcome::Finish, EventOutcome::Consume};
+        }
+        else
+        {
+            return {ThreadOutcome::Continue, EventOutcome::Consume};
+        }
+    }
+    else
+    {
+        return {};
+    }
+}
+
+auto RegistrationThread::capls(IrcMsg const& msg) -> Thread::callback_result
+{
+    auto const n = msg.args.size();
+    if ("CAP" == msg.command && n >= 2 && "*" == msg.args[0] && "LS" == msg.args[1])
+    {
+        std::string_view const* kvs;
+        bool last;
+
+        if (3 == n)
+        {
+            kvs = &msg.args[2];
+            last = true;
+        }
+        else if (4 == n && "*" == msg.args[2])
+        {
+            kvs = &msg.args[3];
+            last = false;
+        }
+        else
+        {
+            return {};
+        }
+
+        auto in = std::istringstream{std::string{*kvs}};
+
+        std::for_each(
+            std::istream_iterator<std::string>{in},
+            std::istream_iterator<std::string>{},
+            [this](std::string x) {
+                auto const eq = x.find('=');
+                if (eq == x.npos)
+                {
+                    caps.emplace(x, std::string{});
+                }
+                else
+                {
+                    caps.emplace(std::string{x, 0, eq}, std::string{x, eq+1, x.npos});
+                }
+            }
+        );
+
+        if (last)
+        {
+            return send_req();
+        }
+
+        return {ThreadOutcome::Continue, EventOutcome::Consume};
+    }
+    else
+    {
+        return {};
+    }
+
+}
+
+auto RegistrationThread::on_msg(IrcMsg const& msg) -> Thread::callback_result
+{
+    switch (stage_)
+    {
+        case Stage::LsReply: return capls(msg);
+        case Stage::AckReply: return capack(msg);
+        default: return {};
+    }
+}
+
+auto RegistrationThread::on_event(Event const& event) -> Thread::callback_result
+{
+    if (auto const irc_event = dynamic_cast<IrcMsgEvent const*>(&event))
+    {
+        return on_msg(irc_event->irc);
+    }
+    if (auto const connect_event = dynamic_cast<ConnectEvent const*>(&event))
+    {
+        return on_connect();
+    }
+    return {};
+}

registration_thread.hpp

@@ -0,0 +1,51 @@
+#pragma once
+
+#include "thread.hpp"
+#include "connection.hpp"
+#include "irc_parse_thread.hpp"
+#include "write_irc.hpp"
+
+#include <string>
+#include <unordered_set>
+#include <unordered_map>
+
+struct RegistrationThread : Thread
+{
+    Connection * connection_;
+    std::string password_;
+    std::string username_;
+    std::string realname_;
+    std::string nickname_;
+
+    std::unordered_map<std::string, std::string> caps;
+    std::unordered_set<std::string> outstanding;
+
+    enum class Stage
+    {
+        LsReply,
+        AckReply,
+    };
+
+    Stage stage_;
+
+    RegistrationThread(
+        Connection * connection_,
+        std::string password,
+        std::string username,
+        std::string realname,
+        std::string nickname
+    );
+
+    auto priority() const -> priority_type override;
+    auto on_connect() -> Thread::callback_result;
+
+    auto send_req() -> Thread::callback_result;
+
+    auto capack(IrcMsg const& msg) -> Thread::callback_result;
+
+    auto capls(IrcMsg const& msg) -> Thread::callback_result;
+
+    auto on_msg(IrcMsg const& msg) -> Thread::callback_result;
+
+    auto on_event(Event const& event) -> Thread::callback_result override;
+};

thread.cpp

@@ -0,0 +1,46 @@
+#include "thread.hpp"
+
+auto Dispatcher::add_thread(std::shared_ptr<Thread> thread) -> void
+{
+    threads_.push_back(std::move(thread));
+}
+
+auto Dispatcher::dispatch(std::shared_ptr<Event> event) -> void
+{
+    if (dispatching_)
+    {
+        events_.push_back(std::move(event));
+        return;
+    }
+
+    dispatching_ = true;
+    std::vector<std::shared_ptr<Event>> events{std::move(event)};
+    while (not events.empty())
+    {
+        for (auto && event : events)
+        {
+            std::vector<std::shared_ptr<Thread>> work;
+            work.swap(threads_);
+            std::sort(work.begin(), work.end(), [](auto const& a, auto const& b) { return a->priority() < b->priority(); });
+
+            std::size_t const n = work.size();
+            for (std::size_t i = 0; i < n; i++)
+            {
+                auto const [thread_outcome, msg_outcome] = work[i]->on_event(*event);
+                if (thread_outcome == ThreadOutcome::Continue)
+                {
+                    threads_.push_back(std::move(work[i]));
+                }
+                if (msg_outcome == EventOutcome::Consume)
+                {
+                    std::move(work.begin() + i + 1, work.end(), std::back_inserter(threads_));
+                    break;
+                }
+            }
+        }
+
+        events = std::move(events_);
+        events_.clear();
+    }
+    dispatching_ = false;
+}

thread.hpp

@@ -0,0 +1,42 @@
+#pragma once
+
+#include "ircmsg.hpp"
+
+#include <memory>
+#include <vector>
+
+enum class EventOutcome
+{
+    Pass,
+    Consume,
+};
+
+enum class ThreadOutcome
+{
+    Continue,
+    Finish,
+};
+
+struct Event {
+    virtual ~Event() {}
+};
+
+struct Thread
+{
+    using priority_type = std::uint64_t;
+    using callback_result = std::pair<ThreadOutcome, EventOutcome>;
+    virtual ~Thread() {}
+    virtual auto on_event(Event const& event) -> callback_result { return {}; };
+    virtual auto priority() const -> priority_type = 0;
+};
+
+struct Dispatcher
+{
+    std::vector<std::shared_ptr<Thread>> threads_;
+    std::vector<std::shared_ptr<Event>> events_;
+    bool dispatching_;
+
+    /// Apply a function to all the threads in priority order
+    auto dispatch(std::shared_ptr<Event> event) -> void;
+    auto add_thread(std::shared_ptr<Thread> thread) -> void;
+};

watchdog_thread.cpp

@@ -0,0 +1,42 @@
+#include "watchdog_thread.hpp"
+
+#include "connection.hpp"
+#include "irc_parse_thread.hpp"
+
+#include <chrono>
+
+using namespace std::chrono_literals;
+
+WatchdogThread::WatchdogThread(Connection * connection) noexcept
+: connection_{connection}
+{
+}
+
+auto WatchdogThread::priority() const -> priority_type
+{
+    return 0;
+}
+
+auto WatchdogThread::on_event(Event const& event) -> std::pair<ThreadOutcome, EventOutcome>
+{
+    if (auto const irc_event = dynamic_cast<LineEvent const*>(&event))
+    {
+        timer_.expires_from_now(30s);
+        return {};
+    }
+    if (auto const connect_event = dynamic_cast<ConnectEvent const*>(&event))
+    {
+        timer_.expires_from_now(30s);
+        timer_.async_wait([weak = weak_from_this()](auto error)
+        {
+            if (not error)
+            {
+                if (auto self = weak.lock())
+                {
+                    self->connection_->close();
+                }
+            }
+        });
+    }
+    return {};
+}

watchdog_thread.hpp

@@ -0,0 +1,18 @@
+#pragma once
+
+#include "thread.hpp"
+#include <boost/asio/steady_timer.hpp>
+
+class Connection;
+
+class WatchdogThread : public Thread, public std::enable_shared_from_this<WatchdogThread>
+{
+    Connection * connection_;
+    boost::asio::steady_timer timer_;
+
+public:
+    WatchdogThread(Connection * connection) noexcept;
+
+    auto priority() const -> priority_type override;
+    auto on_event(Event const& event) -> std::pair<ThreadOutcome, EventOutcome> override;
+};

write_irc.cpp

@@ -0,0 +1,23 @@
+#include "write_irc.hpp"
+
+auto write_irc(Connection& connection, std::string message) -> void
+{
+    message += "\r\n";
+    connection.write_raw(std::move(message));
+}
+
+auto write_irc(Connection& connection, std::string front, std::string_view last) -> void
+{
+    auto const is_invalid = [](char x) -> bool {
+        return x == '\0' || x == '\r' || x == '\n';
+    };
+
+    if (last.end() != std::find_if(last.begin(), last.end(), is_invalid))
+    {
+        throw std::runtime_error{"bad irc argument"};
+    }
+
+    front += " :";
+    front += last;
+    write_irc(connection, std::move(front));
+}

write_irc.hpp

@@ -0,0 +1,24 @@
+#pragma once
+
+#include "connection.hpp"
+
+auto write_irc(Connection& connection, std::string message) -> void;
+
+auto write_irc(Connection& connection, std::string front, std::string_view last) -> void;
+
+template <typename... Args>
+auto write_irc(Connection& connection, std::string front, std::string_view next, Args ...rest) -> void
+{
+    auto const is_invalid = [](char x) -> bool {
+        return x == '\0' || x == '\r' || x == '\n' || x == ' ';
+    };
+
+    if (next.empty() || next.end() != std::find_if(next.begin(), next.end(), is_invalid))
+    {
+        throw std::runtime_error{"bad irc argument"};
+    }
+
+    front += " ";
+    front += next;
+    write_irc(connection, std::move(front), rest...);
+}