ensure data safety

src/engine.cpp

@@ -40,6 +40,11 @@ std::string TicketSystemEngine::Execute(const std::string &command) {
 // LOG->debug("refund_ticket_hash: {}", refund_ticket_hash);
 // LOG->debug("clean_hash: {}", clean_hash);
 // LOG->debug("exit_hash: {}", exit_hash);
+#ifdef ENABLE_ADVANCED_FEATURE
+  if (server_exit_flag) {
+    return "server is exiting, this request is rejected.";
+  }
+#endif
   char command_name[20];
   sscanf(command.c_str(), "%*s %s", command_name);
   hash_t command_name_hash = SplitMix64Hash(std::string_view(command_name));

src/include/engine.h

@@ -3,8 +3,16 @@
 #include <map>
 #include <string>
 #ifdef ENABLE_ADVANCED_FEATURE
+#include <atomic>
+#include <shared_mutex>
 #include "dataguard/dataguard.h"
 #include "dataguard/snapshot.h"
+#define AcquireReadAccess std::shared_lock<std::shared_mutex> read_lock(command_mutex)
+#define AcquireWriteAccess std::unique_lock<std::shared_mutex> write_lock(command_mutex)
+#include <sockpp/tcp_acceptor.h>
+#else
+#define AcquireReadAccess
+#define AcquireWriteAccess
 #endif
 #include <vector>
 #include "data.h"
@@ -15,6 +23,9 @@
 class TicketSystemEngine {
 #ifdef ENABLE_ADVANCED_FEATURE
   SnapShotManager snapshot_manager;
+  std::atomic<bool> server_exit_flag = false;
+  std::shared_mutex command_mutex;
+  friend void handle_client(sockpp::tcp_socket client, TicketSystemEngine &engine);
 #endif
   bool its_time_to_exit = false;
   std::string data_directory;
@@ -56,7 +67,8 @@ class TicketSystemEngine {
                      std::string &res_train2_id, int &res_train1_leaving_time_stamp,
                      int &res_train1_arriving_time_stamp, int &res_train2_leaving_time_stamp,
                      int &res_train2_arriving_time_stamp, int &res_train1_price, int &res_train1_seat,
-                     int &res_train2_price, int &res_train2_seat, std::string &res_transfer_station_name, bool sort_by_time);
+                     int &res_train2_price, int &res_train2_seat, std::string &res_transfer_station_name,
+                     bool sort_by_time);
 
  public:
   const bool *its_time_to_exit_ptr = &its_time_to_exit;

src/main.cpp

@@ -54,6 +54,8 @@ void handle_client(sockpp::tcp_socket client, TicketSystemEngine &engine) {
 
         // 检查是否需要退出
         if (*engine.its_time_to_exit_ptr) {
+          engine.server_exit_flag = true;
+          std::unique_lock<std::shared_mutex> write_lock(engine.command_mutex);
           (&engine)->~TicketSystemEngine();
           exit(0);
           return;

src/train_system.cpp

@@ -10,6 +10,7 @@
 #include "utils.h"
 
 std::string TicketSystemEngine::AddTrain(const std::string &command) {
+  AcquireWriteAccess;
   command_id_t command_id;
   sscanf(command.c_str(), "[%llu]", &command_id);
   LOG->debug("command id: {}", command_id);
@@ -181,6 +182,7 @@ std::string TicketSystemEngine::AddTrain(const std::string &command) {
 }
 
 std::string TicketSystemEngine::DeleteTrain(const std::string &command) {
+  AcquireWriteAccess;
   command_id_t command_id;
   sscanf(command.c_str(), "[%llu]", &command_id);
   LOG->debug("command id: {}", command_id);
@@ -220,6 +222,7 @@ std::string TicketSystemEngine::DeleteTrain(const std::string &command) {
 }
 
 std::string TicketSystemEngine::ReleaseTrain(const std::string &command) {
+  AcquireWriteAccess;
   command_id_t command_id;
   sscanf(command.c_str(), "[%llu]", &command_id);
   LOG->debug("command id: {}", command_id);
@@ -280,6 +283,7 @@ std::string TicketSystemEngine::ReleaseTrain(const std::string &command) {
 }
 
 std::string TicketSystemEngine::QueryTrain(const std::string &command) {
+  AcquireReadAccess;
   command_id_t command_id;
   sscanf(command.c_str(), "[%llu]", &command_id);
   LOG->debug("command id: {}", command_id);

src/transaction_system.cpp

@@ -11,6 +11,7 @@
 #include "utils.h"
 
 std::string TicketSystemEngine::QueryTicket(const std::string &command) {
+  AcquireReadAccess;
   command_id_t command_id;
   sscanf(command.c_str(), "[%llu]", &command_id);
   LOG->debug("command id: {}", command_id);
@@ -124,6 +125,7 @@ std::string TicketSystemEngine::QueryTicket(const std::string &command) {
 }
 
 std::string TicketSystemEngine::QueryTransfer(const std::string &command) {
+  AcquireReadAccess;
   command_id_t command_id;
   sscanf(command.c_str(), "[%llu]", &command_id);
   LOG->debug("command id: {}", command_id);
@@ -386,6 +388,7 @@ void TicketSystemEngine::CheckTransfer(hash_t train1_ID_hash, hash_t train2_ID_h
 }
 
 std::string TicketSystemEngine::BuyTicket(const std::string &command) {
+  AcquireWriteAccess;
   command_id_t command_id;
   sscanf(command.c_str(), "[%llu]", &command_id);
   LOG->debug("command id: {}", command_id);
@@ -493,6 +496,7 @@ std::string TicketSystemEngine::BuyTicket(const std::string &command) {
 }
 
 std::string TicketSystemEngine::QueryOrder(const std::string &command) {
+  AcquireReadAccess;
   command_id_t command_id;
   sscanf(command.c_str(), "[%llu]", &command_id);
   LOG->debug("command id: {}", command_id);
@@ -546,6 +550,7 @@ std::string TicketSystemEngine::QueryOrder(const std::string &command) {
 }
 
 std::string TicketSystemEngine::RefundTicket(const std::string &command) {
+  AcquireWriteAccess;
   command_id_t command_id;
   sscanf(command.c_str(), "[%llu]", &command_id);
   LOG->debug("command id: {}", command_id);

src/user_system.cpp

@@ -9,6 +9,7 @@
 #include "utils.h"
 
 std::string TicketSystemEngine::AddUser(const std::string &command) {
+  AcquireWriteAccess;
   command_id_t command_id;
   sscanf(command.c_str(), "[%llu]", &command_id);
   LOG->debug("command id: {}", command_id);
@@ -101,6 +102,7 @@ std::string TicketSystemEngine::AddUser(const std::string &command) {
 }
 
 std::string TicketSystemEngine::LoginUser(const std::string &command) {
+  AcquireReadAccess;
   command_id_t command_id;
   sscanf(command.c_str(), "[%llu]", &command_id);
   LOG->debug("command id: {}", command_id);
@@ -144,6 +146,7 @@ std::string TicketSystemEngine::LoginUser(const std::string &command) {
 }
 
 std::string TicketSystemEngine::LogoutUser(const std::string &command) {
+  AcquireReadAccess;
   command_id_t command_id;
   sscanf(command.c_str(), "[%llu]", &command_id);
   LOG->debug("command id: {}", command_id);
@@ -171,6 +174,7 @@ std::string TicketSystemEngine::LogoutUser(const std::string &command) {
 }
 
 std::string TicketSystemEngine::QueryProfile(const std::string &command) {
+  AcquireReadAccess;
   command_id_t command_id;
   sscanf(command.c_str(), "[%llu]", &command_id);
   LOG->debug("command id: {}", command_id);
@@ -221,6 +225,7 @@ std::string TicketSystemEngine::QueryProfile(const std::string &command) {
 }
 
 std::string TicketSystemEngine::ModifyProfile(const std::string &command) {
+  AcquireWriteAccess;
   command_id_t command_id;
   sscanf(command.c_str(), "[%llu]", &command_id);
   LOG->debug("command id: {}", command_id);