muduo 27 Acceptor 的封装

#ifndef MUDUO_NET_ACCEPTOR_H
#define MUDUO_NET_ACCEPTOR_H

#include <boost/function.hpp>
#include <boost/noncopyable.hpp>

#include <muduo/net/Channel.h>
#include <muduo/net/Socket.h>

namespace muduo
{
namespace net
{

class EventLoop;
class InetAddress;

///
/// Acceptor of incoming TCP connections.
///
class Acceptor : boost::noncopyable
{
 public:
  typedef boost::function<void (int sockfd,
                                const InetAddress&)> NewConnectionCallback;

  Acceptor(EventLoop* loop, const InetAddress& listenAddr);
  ~Acceptor();

  void setNewConnectionCallback(const NewConnectionCallback& cb)
  { newConnectionCallback_ = cb; }

  bool listenning() const { return listenning_; }
  void listen();

 private:
  void handleRead();

  EventLoop* loop_;       // 对应的事件循环
  Socket acceptSocket_;
  Channel acceptChannel_; // 通道观察socketfd的可读事件
  NewConnectionCallback newConnectionCallback_; // 新连接到来的回调函数
  bool listenning_;      // 释放监听中
  int idleFd_;
};

}
}

#endif  // MUDUO_NET_ACCEPTOR_H

#include <muduo/net/Acceptor.h>

#include <muduo/net/EventLoop.h>
#include <muduo/net/InetAddress.h>
#include <muduo/net/SocketsOps.h>

#include <boost/bind.hpp>

#include <errno.h>
#include <fcntl.h>
//#include <sys/types.h>
//#include <sys/stat.h>

using namespace muduo;
using namespace muduo::net;

Acceptor::Acceptor(EventLoop* loop, const InetAddress& listenAddr)
  : loop_(loop),
    acceptSocket_(sockets::createNonblockingOrDie()),
    acceptChannel_(loop, acceptSocket_.fd()),
    listenning_(false),
    idleFd_(::open("/dev/null", O_RDONLY | O_CLOEXEC))
{
  assert(idleFd_ >= 0);
  acceptSocket_.setReuseAddr(true);     // 设置地址重复利用
  acceptSocket_.bindAddress(listenAddr);
  acceptChannel_.setReadCallback(       // 设置通道有读事件的时候的回调函数
      boost::bind(&Acceptor::handleRead, this));
}

Acceptor::~Acceptor()
{
  acceptChannel_.disableAll();
  acceptChannel_.remove();
  ::close(idleFd_);
}

void Acceptor::listen()
{
  loop_->assertInLoopThread();
  listenning_ = true;
  acceptSocket_.listen();
  acceptChannel_.enableReading();
}

void Acceptor::handleRead()
{
  loop_->assertInLoopThread();
  InetAddress peerAddr(0);
  //FIXME loop until no more
  int connfd = acceptSocket_.accept(&peerAddr); // 调用socket的accept来等待客户端的连接
  if (connfd >= 0)
  {
    // string hostport = peerAddr.toIpPort();
    // LOG_TRACE << "Accepts of " << hostport;
    if (newConnectionCallback_)
    {
      newConnectionCallback_(connfd, peerAddr); // 连接到来调用新连接的回调函数来处理
    }
    else
    {
      sockets::close(connfd);
    }
  }
  else
  {
    // By Marc Lehmann, author of livev. 优雅的关闭错误的fd  先准备一个空闲的fd来连接
    if (errno == EMFILE) // EMFILE too many fd 处理太多的链接
    {
      ::close(idleFd_);
      idleFd_ = ::accept(acceptSocket_.fd(), NULL, NULL);
      ::close(idleFd_);
      idleFd_ = ::open("/dev/null", O_RDONLY | O_CLOEXEC); // 由于是电平触发这里准备一个空闲的文件描述符
    }
  }
}