C++ Style Guide MCP Server

{ "singleton": { "name": "单例模式 (Singleton)", "category": "创建型模式", "intent": "确保一个类只有一个实例，并提供全局访问点", "use_cases": [ "配置管理器", "日志系统", "线程池", "数据库连接池" ], "modern_cpp": "C++11", "example": "// 线程安全的单例模式 (C++11 Meyers' Singleton)\nclass Singleton {\npublic:\n // 删除拷贝构造和赋值运算符\n Singleton(const Singleton&) = delete;\n Singleton& operator=(const Singleton&) = delete;\n\n // 获取单例实例\n static Singleton& getInstance() {\n static Singleton instance; // C++11 保证线程安全\n return instance;\n }\n\n void doSomething() {\n // 业务逻辑\n }\n\nprivate:\n Singleton() = default; // 私有构造函数\n ~Singleton() = default;\n};\n\n// 使用方式\nSingleton::getInstance().doSomething();", "pros": [ "控制实例数量", "全局访问点", "延迟初始化" ], "cons": [ "全局状态，难以测试", "可能导致紧耦合", "多线程需要特别注意" ], "alternatives": "依赖注入、服务定位器" }, "factory": { "name": "工厂模式 (Factory)", "category": "创建型模式", "intent": "定义创建对象的接口，让子类决定实例化哪个类", "use_cases": [ "根据配置创建不同类型的对象", "插件系统", "跨平台代码", "对象池" ], "modern_cpp": "C++11", "example": "// 产品基类\nclass Shape {\npublic:\n virtual ~Shape() = default;\n virtual void draw() const = 0;\n};\n\n// 具体产品\nclass Circle : public Shape {\npublic:\n void draw() const override {\n std::cout << \"Drawing Circle\\n\";\n }\n};\n\nclass Rectangle : public Shape {\npublic:\n void draw() const override {\n std::cout << \"Drawing Rectangle\\n\";\n }\n};\n\n// 工厂类 (使用智能指针)\nclass ShapeFactory {\npublic:\n enum class ShapeType { Circle, Rectangle };\n\n static std::unique_ptr<Shape> createShape(ShapeType type) {\n switch (type) {\n case ShapeType::Circle:\n return std::make_unique<Circle>();\n case ShapeType::Rectangle:\n return std::make_unique<Rectangle>();\n default:\n return nullptr;\n }\n }\n};\n\n// 使用方式\nauto shape = ShapeFactory::createShape(ShapeFactory::ShapeType::Circle);\nshape->draw();", "pros": [ "解耦对象创建和使用", "易于扩展新类型", "符合开闭原则" ], "cons": [ "增加代码复杂度", "每种产品都需要具体类" ] }, "observer": { "name": "观察者模式 (Observer)", "category": "行为型模式", "intent": "定义对象间的一对多依赖关系，当一个对象状态改变时，所有依赖者都会收到通知", "use_cases": [ "事件系统", "MVC 架构中的视图更新", "发布-订阅系统", "实时数据更新" ], "modern_cpp": "C++11", "example": "// 观察者接口\nclass Observer {\npublic:\n virtual ~Observer() = default;\n virtual void update(const std::string& message) = 0;\n};\n\n// 主题/被观察者\nclass Subject {\npublic:\n void attach(std::shared_ptr<Observer> observer) {\n observers_.push_back(observer);\n }\n\n void detach(std::shared_ptr<Observer> observer) {\n observers_.erase(\n std::remove(observers_.begin(), observers_.end(), observer),\n observers_.end()\n );\n }\n\n void notify(const std::string& message) {\n for (auto& observer : observers_) {\n if (auto obs = observer.lock()) {\n obs->update(message);\n }\n }\n }\n\nprivate:\n std::vector<std::weak_ptr<Observer>> observers_;\n};\n\n// 具体观察者\nclass ConcreteObserver : public Observer {\npublic:\n explicit ConcreteObserver(std::string name) : name_(std::move(name)) {}\n\n void update(const std::string& message) override {\n std::cout << name_ << \" received: \" << message << \"\\n\";\n }\n\nprivate:\n std::string name_;\n};\n\n// 使用方式\nSubject subject;\nauto obs1 = std::make_shared<ConcreteObserver>(\"Observer1\");\nauto obs2 = std::make_shared<ConcreteObserver>(\"Observer2\");\n\nsubject.attach(obs1);\nsubject.attach(obs2);\nsubject.notify(\"Hello Observers!\");", "pros": [ "松耦合", "支持广播通信", "符合开闭原则" ], "cons": [ "可能导致意外更新", "观察者顺序不确定", "内存泄漏风险（使用 weak_ptr 解决）" ] }, "raii": { "name": "RAII (资源获取即初始化)", "category": "C++ 惯用法", "intent": "利用对象生命周期自动管理资源", "use_cases": [ "文件句柄", "内存管理", "锁管理", "数据库连接" ], "modern_cpp": "C++11", "example": "// RAII 文件管理器\nclass FileHandler {\npublic:\n explicit FileHandler(const std::string& filename) \n : file_(filename) {\n if (!file_.is_open()) {\n throw std::runtime_error(\"Failed to open file\");\n }\n }\n\n // 禁止拷贝\n FileHandler(const FileHandler&) = delete;\n FileHandler& operator=(const FileHandler&) = delete;\n\n // 允许移动\n FileHandler(FileHandler&&) = default;\n FileHandler& operator=(FileHandler&&) = default;\n\n ~FileHandler() {\n if (file_.is_open()) {\n file_.close();\n }\n }\n\n void write(const std::string& data) {\n file_ << data;\n }\n\nprivate:\n std::fstream file_;\n};\n\n// 使用方式 - 无需手动关闭文件\nvoid processFile(const std::string& filename) {\n FileHandler handler(filename);\n handler.write(\"Hello, RAII!\");\n // 离开作用域时自动关闭文件\n}\n\n// RAII 锁管理\nvoid threadSafeOperation() {\n std::mutex mtx;\n std::lock_guard<std::mutex> lock(mtx);\n // 临界区代码\n // 离开作用域时自动解锁\n}", "pros": [ "异常安全", "不会忘记释放资源", "代码简洁" ], "cons": [ "需要理解对象生命周期" ], "related": "智能指针、std::lock_guard、std::unique_lock" }, "pimpl": { "name": "Pimpl (指向实现的指针)", "category": "C++ 惯用法", "intent": "将实现细节从接口中分离，减少编译依赖", "use_cases": [ "隐藏实现细节", "减少头文件依赖", "ABI 稳定性", "编译时间优化" ], "modern_cpp": "C++11", "example": "// Widget.h - 公开接口\nclass Widget {\npublic:\n Widget();\n ~Widget(); // 必须在 .cpp 中定义\n\n // 禁止拷贝（或实现深拷贝）\n Widget(const Widget&) = delete;\n Widget& operator=(const Widget&) = delete;\n\n // 允许移动\n Widget(Widget&&) noexcept;\n Widget& operator=(Widget&&) noexcept;\n\n void doSomething();\n int getValue() const;\n\nprivate:\n class Impl; // 前向声明\n std::unique_ptr<Impl> pImpl_; // 指向实现的指针\n};\n\n// Widget.cpp - 实现\nclass Widget::Impl {\npublic:\n void doSomething() {\n // 实现细节\n }\n \n int getValue() const {\n return value_;\n }\n\nprivate:\n int value_ = 0;\n std::vector<int> data_; // 不会出现在公开头文件中\n};\n\nWidget::Widget() : pImpl_(std::make_unique<Impl>()) {}\nWidget::~Widget() = default;\nWidget::Widget(Widget&&) noexcept = default;\nWidget& Widget::operator=(Widget&&) noexcept = default;\n\nvoid Widget::doSomething() {\n pImpl_->doSomething();\n}\n\nint Widget::getValue() const {\n return pImpl_->getValue();\n}", "pros": [ "隐藏实现细节", "减少编译依赖", "二进制兼容性", "减少头文件包含" ], "cons": [ "增加间接层", "轻微性能开销", "需要额外的内存分配" ] }, "strategy": { "name": "策略模式 (Strategy)", "category": "行为型模式", "intent": "定义一系列算法，把它们封装起来，并且使它们可以互相替换", "use_cases": [ "排序算法选择", "压缩算法", "支付方式", "验证策略" ], "modern_cpp": "C++11", "example": "// 策略接口\nclass CompressionStrategy {\npublic:\n virtual ~CompressionStrategy() = default;\n virtual std::vector<uint8_t> compress(const std::vector<uint8_t>& data) = 0;\n};\n\n// 具体策略\nclass ZipCompression : public CompressionStrategy {\npublic:\n std::vector<uint8_t> compress(const std::vector<uint8_t>& data) override {\n // ZIP 压缩实现\n return data; // 简化示例\n }\n};\n\nclass GzipCompression : public CompressionStrategy {\npublic:\n std::vector<uint8_t> compress(const std::vector<uint8_t>& data) override {\n // GZIP 压缩实现\n return data; // 简化示例\n }\n};\n\n// 上下文类\nclass Compressor {\npublic:\n void setStrategy(std::unique_ptr<CompressionStrategy> strategy) {\n strategy_ = std::move(strategy);\n }\n\n std::vector<uint8_t> compress(const std::vector<uint8_t>& data) {\n if (!strategy_) {\n throw std::runtime_error(\"No strategy set\");\n }\n return strategy_->compress(data);\n }\n\nprivate:\n std::unique_ptr<CompressionStrategy> strategy_;\n};\n\n// 使用方式\nCompressor compressor;\ncompressor.setStrategy(std::make_unique<ZipCompression>());\nauto result = compressor.compress(data);\n\n// 运行时切换策略\ncompressor.setStrategy(std::make_unique<GzipCompression>());\nresult = compressor.compress(data);", "pros": [ "算法可以自由切换", "避免大量条件语句", "易于扩展新算法" ], "cons": [ "客户端需要了解不同策略", "增加对象数量" ] } }