c++怎么实现一个RAII风格的文件或Socket句柄封装_c++资源自动释放与异常安全

class FileHandle {
public:
    explicit FileHandle(int fd = -1) : m_fd(fd) {}

    // 禁止拷贝，防止重复关闭
    FileHandle(const FileHandle&) = delete;
    FileHandle& operator=(const FileHandle&) = delete;

    // 支持移动语义
    FileHandle(FileHandle&& other) noexcept : m_fd(other.m_fd) {
        other.m_fd = -1;
    }

    FileHandle& operator=(FileHandle&& other) noexcept {
        if (this != &other) {
            close();
            m_fd = other.m_fd;
            other.m_fd = -1;
        }
        return *this;
    }

    ~FileHandle() {
        close();
    }

    int get() const { return m_fd; }
    bool is_valid() const { return m_fd >= 0; }

private:
    void close() {
        if (m_fd >= 0) {
            ::close(m_fd);
            m_fd = -1;
        }
    }

    int m_fd;
};

void read_config() {
    FileHandle fh(open("/etc/config.txt", O_RDONLY));
    if (!fh.is_valid()) {
        throw std::runtime_error("无法打开配置文件");
    }
    
    char buffer[1024];
    ssize_t n = read(fh.get(), buffer, sizeof(buffer));
    // 使用完后自动关闭，无需显式调用close
}

class SocketHandle {
public:
    explicit SocketHandle(int sock = -1) : m_sock(sock) {}

    SocketHandle(const SocketHandle&) = delete;
    SocketHandle& operator=(const SocketHandle&) = delete;

    SocketHandle(SocketHandle&& other) noexcept : m_sock(other.m_sock) {
        other.m_sock = -1;
    }

    SocketHandle& operator=(SocketHandle&& other) noexcept {
        if (this != &other) {
            close();
            m_sock = other.m_sock;
            other.m_sock = -1;
        }
        return *this;
    }

    ~SocketHandle() {
        close();
    }

    int get() const { return m_sock; }
    bool is_valid() const { return m_sock >= 0; }

    // 提供常用操作接口
    void shutdown_read_write() {
        if (is_valid()) {
            ::shutdown(m_sock, SHUT_RDWR);
        }
    }

private:
    void close() {
        if (m_sock >= 0) {
            ::close(m_sock);
            m_sock = -1;
        }
    }

    int m_sock;
};

void handle_client(int client_sock) {
    SocketHandle sock(client_sock);

    // 模拟处理过程可能抛异常
    if (some_error_condition) {
        throw std::runtime_error("客户端协议错误");
    }

    // 正常通信...
    send(sock.get(), "Hello", 5, 0);
    // 函数返回时自动关闭socket
}

auto socket_deleter = [](int sock) {
    if (sock >= 0) closesocket(sock);
};
std::unique_ptr<int, decltype(socket_deleter)> sock_ptr(socket(AF_INET, SOCK_STREAM, 0), socket_deleter);