ChessEngine: Handle the UCI quit command

Author: https://github.com/tcl3
Commit: c2b9376409
Pull-request: https://github.com/SerenityOS/serenity/pull/18140
Issue: https://github.com/SerenityOS/serenity/issues/17427
Reviewed-by: https://github.com/LucasChollet
Reviewed-by: https://github.com/petelliott

Userland/Services/ChessEngine/ChessEngine.cpp

@@ -62,3 +62,9 @@ void ChessEngine::handle_go(GoCommand const& command)
 
     m_last_tree = move(best_node);
 }
+
+void ChessEngine::handle_quit()
+{
+    if (on_quit)
+        on_quit(ESUCCESS);
+}

Userland/Services/ChessEngine/ChessEngine.h

@@ -18,6 +18,9 @@ public:
     virtual void handle_uci() override;
     virtual void handle_position(Chess::UCI::PositionCommand const&) override;
     virtual void handle_go(Chess::UCI::GoCommand const&) override;
+    virtual void handle_quit() override;
+
+    Function<void(int)> on_quit;
 
 private:
     ChessEngine() = default;

Userland/Services/ChessEngine/main.cpp

@@ -17,5 +17,9 @@ ErrorOr<int> serenity_main(Main::Arguments)
     TRY(Core::System::unveil(nullptr, nullptr));
 
     auto engine = TRY(ChessEngine::try_create(Core::DeprecatedFile::standard_input(), Core::DeprecatedFile::standard_output()));
+    engine->on_quit = [&](auto status_code) {
+        loop.quit(status_code);
+    };
+
     return loop.exec();
 }