32muduo_net库源码分析（八）

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1.Acceptor

（1）Acceptor用于accept(2)接受TCP连接

（2）Acceptor的数据成员包括Socket、Channel，Acceptor的socket是listening socket（即serversocket）。Channel用于观察此socket的readable事件，并回调Accptor::handleRead()，后者调用accept(2)来接受新连接，并回调用户callback。

2.代码

1.Acceptor.h

// Copyright 2010, Shuo Chen.  All rights reserved.
// http://code.google.com/p/muduo/
//
// Use of this source code is governed by a BSD-style license
// that can be found in the License file.

// Author: Shuo Chen (chenshuo at chenshuo dot com)
//
// This is an internal header file, you should not include this.

#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_;
  Socket acceptSocket_;
  Channel acceptChannel_;
  NewConnectionCallback newConnectionCallback_;
  bool listenning_;
  int idleFd_;
};

}
}

#endif  // MUDUO_NET_ACCEPTOR_H

2.Acceptor.cc

// Copyright 2010, Shuo Chen.  All rights reserved.
// http://code.google.com/p/muduo/
//
// Use of this source code is governed by a BSD-style license
// that can be found in the License file.

// Author: Shuo Chen (chenshuo at chenshuo dot com)

#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);
  acceptSocket_.bindAddress(listenAddr);
  acceptChannel_.setReadCallback(
      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);
  if (connfd >= 0)
  {
    // string hostport = peerAddr.toIpPort();
    // LOG_TRACE << "Accepts of " << hostport;
    if (newConnectionCallback_)
    {
      newConnectionCallback_(connfd, peerAddr);
    }
    else
    {
      sockets::close(connfd);
    }
  }
  else
  {
    // Read the section named "The special problem of
    // accept()ing when you can't" in libev's doc.
    // By Marc Lehmann, author of livev.
    if (errno == EMFILE)
    {
      ::close(idleFd_);
      idleFd_ = ::accept(acceptSocket_.fd(), NULL, NULL);
      ::close(idleFd_);
      idleFd_ = ::open("/dev/null", O_RDONLY | O_CLOEXEC);
    }
  }
}

3.Accepotr示例

void newConnection(int sockfd, const InetAddress& peerAddr)
{
  printf("newConnection(): accepted a new connection from %s\n",
         peerAddr.toIpPort().c_str());
  ::write(sockfd, "How are you?\n", 13);
  sockets::close(sockfd);
}

int main()
{
  printf("main(): pid = %d\n", getpid());

  InetAddress listenAddr(8888);
  EventLoop loop;

  Acceptor acceptor(&loop, listenAddr);
  acceptor.setNewConnectionCallback(newConnection);
  acceptor.listen();

  loop.loop();
}