我有一个看起来像这样的课:
class MyConnector : public boost::noncopyable, public boost::enable_shared_from_this<MyConnector>
{
public:
typedef MyConnector this_type;
boost::asio::ip::tcp::socket _plainSocket;
boost::shared_ptr<std::vector<uint8_t>> _readBuffer;
// lot of obvious stuff removed....
void readProtocol()
{
_readBuffer = boost::make_shared<std::vector<uint8_t>>(12, 0);
boost::asio::async_read(_plainSocket, boost::asio::buffer(&_readBuffer->at(0), 12),
boost::bind(&this_type::handleReadProtocol, shared_from_this(),
boost::asio::placeholders::bytes_transferred, boost::asio::placeholders::error));
}
void handleReadProtocol(size_t bytesRead,const boost::system::error_code& error)
{
// handling code removed
}
};
此类实例通常在尝试读取完整消息之前正在等待接收12个字节的协议。但是,当我尝试取消此读取操作并销毁对象时,不会发生。当我调用_plainSocket.cancel(ec)时,它不使用该ec调用handleReadProtocol。套接字断开连接,但未调用处理程序。
boost::system::error_code ec;
_plainSocket.cancel(ec);
并且不释放使用shared_from_this()传递的MyConnector对象的shared_ptr。该对象在堆内存中仍然像僵尸一样。如何以减少MyConnector对象引用计数的方式取消async_read(),从而允许对象自行销毁?
答案 0 :(得分:0)
两件事情:一,在handleReadProtocol
中,请确保如果发生错误,则不会调用readProtocol
。已取消的操作仍会调用处理程序,但设置了错误代码。
第二,如果您已完成连接,则asio建议关闭并关闭套接字。例如:
asio::post([this] {
if (_plainSocket.is_open()) {
asio::error_code ec;
/* For portable behaviour with respect to graceful closure of a connected socket, call
* shutdown() before closing the socket. */
_plainSocket.shutdown(asio::ip::tcp::socket::shutdown_both, ec);
if (ec) {
Log(fmt::format("Socket shutdown error {}.", ec.message()));
ec.clear();
}
_plainSocket.close(ec);
if (ec)
Log(fmt::format("Socket close error {}.", ec.message()));
}
});