Fix errors of unable to run in OJ

src/CMakeLists.txt

@@ -8,5 +8,7 @@ target_link_libraries(${BACKEND_EXETUABLE_NAME} argparse)
 target_link_libraries(${BACKEND_EXETUABLE_NAME} spdlog::spdlog)
 target_link_libraries(${BACKEND_EXETUABLE_NAME} sockpp)
 target_link_libraries(${BACKEND_EXETUABLE_NAME} storage)
-target_link_libraries(${BACKEND_EXETUABLE_NAME} dataguard)
+if(ENABLE_ADVANCED_FEATURE)
+  target_link_libraries(${BACKEND_EXETUABLE_NAME} dataguard)
+endif()
 set_target_properties(${BACKEND_EXETUABLE_NAME} PROPERTIES RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR})

src/engine.cpp

@@ -97,7 +97,7 @@ std::string TicketSystemEngine::Execute(const std::string &command) {
   throw std::invalid_argument("Invalid command.");
 }
 
-std::string TicketSystemEngine::Clean() { return "Clean"; }
+std::string TicketSystemEngine::Clean() { throw std::runtime_error("Command clean is not implemented"); }
 
 std::string TicketSystemEngine::Exit(const std::string &command) {
   command_id_t command_id;

src/main.cpp

@@ -1,7 +1,10 @@
 #include <sockpp/tcp_acceptor.h>
+#include <cassert>
 #include <exception>
 #include "basic_defs.h"
+#ifdef ENABLE_ADVANCED_FEATURE
 #include "dataguard/dataguard.h"
+#endif
 #include "engine.h"
 #include "storage/bpt.hpp"
 const std::string main_version = "0.0.1";
@@ -86,6 +89,7 @@ int main(int argc, char *argv[]) {
   bool is_server = program.is_subcommand_used("server");
   LOG->info("Server mode: {}", is_server);
   try {
+#ifdef ENABLE_ADVANCED_FEATURE
     if (is_server) {
       auto port = server_command.get<int>("--port");
       auto address = server_command.get<std::string>("--address");
@@ -100,6 +104,7 @@ int main(int argc, char *argv[]) {
         LOG->info("successfully bind to address {} port {}", address, port);
       throw std::runtime_error("Server mode not implemented");
     } else {
+#endif
       std::ios::sync_with_stdio(false);
       std::cin.tie(nullptr);
       std::cout.tie(nullptr);
@@ -107,9 +112,10 @@ int main(int argc, char *argv[]) {
       std::string cmd;
       while (std::getline(std::cin, cmd)) {
         std::cout << engine.Execute(cmd) << '\n';
-        std::cout.flush();
       }
+#ifdef ENABLE_ADVANCED_FEATURE
     }
+#endif
   } catch (std::exception &e) {
     LOG->error("Exception: {}", e.what());
     return 1;