lazy snote matching

main.cpp

@@ -62,6 +62,14 @@ auto start(boost::asio::io_context & io, Settings const& settings) -> void
     CommandThread::start(*connection);
     echo_thread(*connection);
 
+    connection->add_listener<SnoteEvent>([](SnoteEvent& event) {
+        std::cout << "SNOTE " << static_cast<int>(event.get_tag()) << std::endl;
+        for (auto c : event.get_results())
+        {
+            std::cout << "    " << std::string_view{c.first, c.second} << std::endl;
+        }
+    });
+
     boost::asio::co_spawn(
         io,
         connection->connect(io, settings.host, settings.service),

snote_thread.cpp

@@ -155,19 +155,7 @@ auto SnoteThread::start(Connection& connection) -> std::shared_ptr<SnoteThread>
             case HS_SCAN_TERMINATED:
             {
                 auto& pattern = patterns[match_id];
-                std::match_results<std::string_view::const_iterator> results;
+                connection.make_event<SnoteEvent>(pattern.tag, pattern.regex, message);
-                if (not std::regex_match(message.begin(), message.end(), results, pattern.regex))
-                {
-                    // something went wrong - hyperscan disagrees with std::regex
-                    abort();
-                }
-
-                std::vector<std::string_view> parts;
-                for (auto const sub : results)
-                {
-                    parts.push_back(std::string_view{sub.first, sub.second});
-                }
-                connection.make_event<SnoteEvent>(pattern.tag, std::move(parts));
                 break;
             }
 
@@ -180,6 +168,28 @@ auto SnoteThread::start(Connection& connection) -> std::shared_ptr<SnoteThread>
     return thread;
 }
 
+auto SnoteEvent::get_tag() const -> SnoteTag
+{
+    return tag_;
+}
+
+auto SnoteEvent::get_results() -> std::match_results<std::string_view::const_iterator> const&
+{
+    if (auto results = std::get_if<1>(&components_)) {
+        return *results;
+    }
+
+    auto& regex = std::get<0>(components_).first;
+    auto message = std::get<0>(components_).second;
+    auto& results = components_.emplace<1>();
+    if (not std::regex_match(message.begin(), message.end(), results, regex))
+    {
+        // something went wrong - hyperscan disagrees with std::regex
+        abort();
+    }
+    return results;
+}
+
 auto SnoteThread::DbDeleter::operator()(hs_database_t * db) const -> void
 {
     if (HS_SUCCESS != hs_free_database(db))

snote_thread.hpp

@@ -3,8 +3,9 @@
 #include "event.hpp"
 
 #include <memory>
+#include <regex>
 #include <string_view>
-#include <vector>
+#include <variant>
 
 class Connection;
 struct hs_database;
@@ -27,15 +28,20 @@ enum class SnoteTag
     Killed,
 };
 
-struct SnoteEvent : Event
+class SnoteEvent : public Event
 {
-    SnoteEvent(SnoteTag tag, std::vector<std::string_view> parts)
+public:
-    : tag{tag}
+    SnoteEvent(SnoteTag tag, std::regex const& regex, std::string_view full)
-    , parts{std::move(parts)}
+    : tag_{tag}
+    , components_{std::make_pair(std::ref(regex), full)}
     {}
 
-    SnoteTag tag;
+    auto get_tag() const -> SnoteTag;
-    std::vector<std::string_view> parts;
+    auto get_results() -> std::match_results<std::string_view::const_iterator> const&;
+
+private:
+    SnoteTag tag_;
+    std::variant<std::pair<std::regex const&, std::string_view>, std::match_results<std::string_view::const_iterator>> components_;
 };
 
 struct SnoteThread