如何解决TcpStream的“移动值”问题？

Question

我正在尝试将数据包/字节从一个TcpStream传输到另一个，反之亦然。我已经创建了一个结构Connection

pub struct Connection {
    pub client_socket: TcpStream,
    pub server_socket: TcpStream
}

我正在尝试打开两个线程，这样我就可以在两个方向上传输所有字节。遗憾的是，我正在尝试使用一个已移动的值，因为我第二次调用了connection。我怎么才能修复它呢？

thread::spawn(move || loop { connection.transfer_server_client_packet(); });
thread::spawn(move || loop { connection.transfer_client_server_packet(); });

impl Connection {
    fn get_packet(&mut self, from_client: bool) -> Result<Packet, io::Error> {
        unimplemented!()
    }
    pub fn get_client_packet(&mut self) -> Result<Packet, io::Error> {
        self.get_packet(true)
    }
    pub fn get_server_packet(&mut self) -> Result<Packet, io::Error> {
        self.get_packet(false)
    }
    fn send_packet(&mut self, from_client: bool, mut packet: Packet) -> Result<Packet, io::Error> {
        unimplemented!()
    }
    pub fn send_client_packet(&mut self, packet: Packet) -> Result<Packet, io::Error> {
        self.send_packet(true, packet)
    }
    pub fn send_server_packet(&mut self, packet: Packet) -> Result<Packet, io::Error> {
        self.send_packet(false, packet)
    }
    fn transfer_packet(&mut self, from_client: bool, to_client: bool) -> Result<usize, io::Error> {
        let packet = if from_client {
            self.get_client_packet()?
        } else {
            self.get_server_packet()?
        };
        if to_client {
            self.send_client_packet(packet)?
        } else {
            self.send_server_packet(packet)?
        };
        Ok(0)
    }
    pub fn transfer_client_server_packet(&mut self) -> Result<usize, io::Error> {
        self.transfer_packet(true, false)
    }
    pub fn transfer_server_client_packet(&mut self) -> Result<usize, io::Error> {
        self.transfer_packet(false, true)
    }
}

Answer 1

一旦移动了一个值--在本例中是Connection --您就不能再使用它了。如果您需要两个线程对同一连接进行可变访问，那么您可以克隆它或使用同步原语共享它，例如Arc。

例如：

let connection = Arc::new(Mutex::new(Connection::new()));
let connection_server_client = Arc::clone(&connection);
let connection_client_server = Arc::clone(&connection);

thread::spawn(move || loop {
    let connection = connection_server_client.lock().unwrap();
    connection.transfer_server_client_packet();
});

thread::spawn(move || loop {
    let connection = connection_client_server.lock().unwrap();
    connection.transfer_client_server_packet();
});

此设置管理共享资源，以便一次只有一个线程可以改变它。它还将确保在两个线程都使用完该资源时删除该资源。

话虽如此，我会考虑重构你的代码:这两个线程实际上并不需要相同的TcpStream。共享变得必要的唯一原因是你已经将两个流存储在同一个结构中，这意味着你不能在不借用另一个的情况下借用其中一个。