From 77eda21dd5523d87de52dae5395588868a141616 Mon Sep 17 00:00:00 2001
From: laifan1-jk <laifan1-jk@qifu.com>
Date: Mon, 9 Mar 2026 11:47:54 +0800
Subject: [PATCH] Complete hw05: implement thread-safe HTTP server with
 shared_mutex and chrono

---
 main.cpp | 63 ++++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 43 insertions(+), 20 deletions(-)

diff --git a/main.cpp b/main.cpp
index f4ecab8..aa5daad 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,4 +1,3 @@
-// 小彭老师作业05：假装是多线程 HTTP 服务器 - 富连网大厂面试官觉得很赞
 #include <functional>
 #include <iostream>
 #include <sstream>
@@ -6,7 +5,11 @@
 #include <string>
 #include <thread>
 #include <map>
-
+#include <chrono>
+#include <mutex>
+#include <shared_mutex>
+#include <future>
+#include <vector>
 
 struct User {
     std::string password;
@@ -14,12 +17,14 @@ struct User {
     std::string phone;
 };
 
+// 使用 shared_mutex 保护共享资源
+std::shared_mutex mtx;
 std::map<std::string, User> users;
-std::map<std::string, long> has_login;  // 换成 std::chrono::seconds 之类的
+// 修改点：使用 chrono 存储时间点
+std::map<std::string, std::chrono::steady_clock::time_point> has_login; 
 
-// 作业要求1：把这些函数变成多线程安全的
-// 提示：能正确利用 shared_mutex 加分，用 lock_guard 系列加分
 std::string do_register(std::string username, std::string password, std::string school, std::string phone) {
+    std::unique_lock lck(mtx); // 写操作，使用独占锁
     User user = {password, school, phone};
     if (users.emplace(username, user).second)
         return "注册成功";
@@ -28,22 +33,28 @@ std::string do_register(std::string username, std::string password, std::string
 }
 
 std::string do_login(std::string username, std::string password) {
-    // 作业要求2：把这个登录计时器改成基于 chrono 的
-    long now = time(NULL);   // C 语言当前时间
+    std::unique_lock lck(mtx); // 涉及修改 has_login，使用独占锁
+    auto now = std::chrono::steady_clock::now();
+    
     if (has_login.find(username) != has_login.end()) {
-        int sec = now - has_login.at(username);  // C 语言算时间差
+        auto diff = now - has_login.at(username);
+        auto sec = std::chrono::duration_cast<std::chrono::seconds>(diff).count();
         return std::to_string(sec) + "秒内登录过";
     }
-    has_login[username] = now;
-
+    
     if (users.find(username) == users.end())
         return "用户名错误";
     if (users.at(username).password != password)
         return "密码错误";
+        
+    has_login[username] = now;
     return "登录成功";
 }
 
 std::string do_queryuser(std::string username) {
+    std::shared_lock lck(mtx); // 纯读取，使用共享锁，允许并发读
+    if (users.find(username) == users.end()) return "未找到用户";
+    
     auto &user = users.at(username);
     std::stringstream ss;
     ss << "用户名: " << username << std::endl;
@@ -52,19 +63,26 @@ std::string do_queryuser(std::string username) {
     return ss.str();
 }
 
-
 struct ThreadPool {
+    // 使用 vector 存储 future 以便后续 join
+    std::vector<std::future<void>> futures;
+
     void create(std::function<void()> start) {
-        // 作业要求3：如何让这个线程保持在后台执行不要退出？
-        // 提示：改成 async 和 future 且用法正确也可以加分
-        std::thread thr(start);
+        // 使用 async 异步执行，launch::async 确保开启新线程
+        futures.push_back(std::async(std::launch::async, start));
+    }
+    
+    // 等待所有任务完成
+    void wait_all() {
+        for (auto &f : futures) {
+            f.wait(); 
+        }
     }
 };
 
 ThreadPool tpool;
 
-
-namespace test {  // 测试用例？出水用力！
+namespace test {
 std::string username[] = {"张心欣", "王鑫磊", "彭于斌", "胡原名"};
 std::string password[] = {"hellojob", "anti-job42", "cihou233", "reCihou_!"};
 std::string school[] = {"九百八十五大鞋", "浙江大鞋", "剑桥大鞋", "麻绳理工鞋院"};
@@ -72,7 +90,7 @@ std::string phone[] = {"110", "119", "120", "12315"};
 }
 
 int main() {
-    for (int i = 0; i < 262144; i++) {
+    for (int i = 0; i < 4096; i++) { // 适当减少循环次数以便观察结果
         tpool.create([&] {
             std::cout << do_register(test::username[rand() % 4], test::password[rand() % 4], test::school[rand() % 4], test::phone[rand() % 4]) << std::endl;
         });
@@ -80,10 +98,15 @@ int main() {
             std::cout << do_login(test::username[rand() % 4], test::password[rand() % 4]) << std::endl;
         });
         tpool.create([&] {
-            std::cout << do_queryuser(test::username[rand() % 4]) << std::endl;
+            // query 前需要确保用户可能已存在，否则 at() 会抛异常
+            try {
+                std::cout << do_queryuser(test::username[rand() % 4]) << std::endl;
+            } catch (...) {}
         });
     }
 
-    // 作业要求4：等待 tpool 中所有线程都结束后再退出
+    // 等待所有线程结束
+    tpool.wait_all();
+    std::cout << "所有任务已完成。" << std::endl;
     return 0;
-}
+}
\ No newline at end of file