欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页

26muduo_net库源码分析(二)

程序员文章站 2022-06-14 10:18:37
...

1.类图

26muduo_net库源码分析(二)

2.Channel

(1)Channelselectable IO channel,负责注册与响应IO事件,它不拥有filedescriptor
(2)ChannelAcceptorConnectorEventLoopTimerQueueTcpConnection的成员,生命期由后者控制。

3.时序图

26muduo_net库源码分析(二)

26muduo_net库源码分析(二)


4.代码

EvevtLoop.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 a public header file, it must only include public header files.

#ifndef MUDUO_NET_EVENTLOOP_H
#define MUDUO_NET_EVENTLOOP_H

#include <vector>

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

#include <muduo/base/CurrentThread.h>
#include <muduo/base/Thread.h>
#include <muduo/base/Timestamp.h>

namespace muduo
{
namespace net
{

class Channel;
class Poller;
///
/// Reactor, at most one per thread.
///
/// This is an interface class, so don't expose too much details.
class EventLoop : boost::noncopyable
{
 public:
  EventLoop();
  ~EventLoop();  // force out-line dtor, for scoped_ptr members.

  ///
  /// Loops forever.
  ///
  /// Must be called in the same thread as creation of the object.
  ///
  void loop();

  void quit();

  ///
  /// Time when poll returns, usually means data arrivial.
  ///
  Timestamp pollReturnTime() const { return pollReturnTime_; }

  // internal usage
  void updateChannel(Channel* channel);		// 在Poller中添加或者更新通道
  void removeChannel(Channel* channel);		// 从Poller中移除通道

  void assertInLoopThread()
  {
    if (!isInLoopThread())
    {
      abortNotInLoopThread();
    }
  }
  bool isInLoopThread() const { return threadId_ == CurrentThread::tid(); }

  static EventLoop* getEventLoopOfCurrentThread();

 private:
  void abortNotInLoopThread();

  void printActiveChannels() const; // DEBUG

  typedef std::vector<Channel*> ChannelList;
  
  bool looping_; /* atomic */
  bool quit_; /* atomic */
  bool eventHandling_; /* atomic */
  const pid_t threadId_;		// 当前对象所属线程ID
  Timestamp pollReturnTime_;
  boost::scoped_ptr<Poller> poller_;
  ChannelList activeChannels_;		// Poller返回的活动通道
  Channel* currentActiveChannel_;	// 当前正在处理的活动通道
};

}
}
#endif  // MUDUO_NET_EVENTLOOP_H

EventLoop.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/EventLoop.h>

#include <muduo/base/Logging.h>
#include <muduo/net/Channel.h>
#include <muduo/net/Poller.h>

//#include <poll.h>

using namespace muduo;
using namespace muduo::net;

namespace
{
// 当前线程EventLoop对象指针
// 线程局部存储
__thread EventLoop* t_loopInThisThread = 0;

const int kPollTimeMs = 10000;
}

EventLoop* EventLoop::getEventLoopOfCurrentThread()
{
  return t_loopInThisThread;
}

EventLoop::EventLoop()
  : looping_(false),
    quit_(false),
    eventHandling_(false),
    threadId_(CurrentThread::tid()),
	poller_(Poller::newDefaultPoller(this)),
	currentActiveChannel_(NULL)
{
  LOG_TRACE << "EventLoop created " << this << " in thread " << threadId_;
  // 如果当前线程已经创建了EventLoop对象,终止(LOG_FATAL)
  if (t_loopInThisThread)
  {
    LOG_FATAL << "Another EventLoop " << t_loopInThisThread
              << " exists in this thread " << threadId_;
  }
  else
  {
    t_loopInThisThread = this;
  }
}

EventLoop::~EventLoop()
{
  t_loopInThisThread = NULL;
}

// 事件循环,该函数不能跨线程调用
// 只能在创建该对象的线程中调用
void EventLoop::loop()
{
  assert(!looping_);
  // 断言当前处于创建该对象的线程中
  assertInLoopThread();
  looping_ = true;
  LOG_TRACE << "EventLoop " << this << " start looping";

  //::poll(NULL, 0, 5*1000);
  while (!quit_)
  {
    activeChannels_.clear();
    pollReturnTime_ = poller_->poll(kPollTimeMs, &activeChannels_);
    //++iteration_;
    if (Logger::logLevel() <= Logger::TRACE)
    {
      printActiveChannels();
    }
    // TODO sort channel by priority
    eventHandling_ = true;
    for (ChannelList::iterator it = activeChannels_.begin();
        it != activeChannels_.end(); ++it)
    {
      currentActiveChannel_ = *it;
      currentActiveChannel_->handleEvent(pollReturnTime_);
    }
    currentActiveChannel_ = NULL;
    eventHandling_ = false;
    //doPendingFunctors();
  }

  LOG_TRACE << "EventLoop " << this << " stop looping";
  looping_ = false;
}

void EventLoop::quit()
{
  quit_ = true;
  if (!isInLoopThread())
  {
    //wakeup();
  }
}

void EventLoop::updateChannel(Channel* channel)
{
  assert(channel->ownerLoop() == this);
  assertInLoopThread();
  poller_->updateChannel(channel);
}

void EventLoop::removeChannel(Channel* channel)
{
  assert(channel->ownerLoop() == this);
  assertInLoopThread();
  if (eventHandling_)
  {
    assert(currentActiveChannel_ == channel ||
        std::find(activeChannels_.begin(), activeChannels_.end(), channel) == activeChannels_.end());
  }
  poller_->removeChannel(channel);
}

void EventLoop::abortNotInLoopThread()
{
  LOG_FATAL << "EventLoop::abortNotInLoopThread - EventLoop " << this
            << " was created in threadId_ = " << threadId_
            << ", current thread id = " <<  CurrentThread::tid();
}

void EventLoop::printActiveChannels() const
{
  for (ChannelList::const_iterator it = activeChannels_.begin();
      it != activeChannels_.end(); ++it)
  {
    const Channel* ch = *it;
    LOG_TRACE << "{" << ch->reventsToString() << "} ";
  }
}

Channel.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_CHANNEL_H
#define MUDUO_NET_CHANNEL_H

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

#include <muduo/base/Timestamp.h>

namespace muduo
{
namespace net
{

class EventLoop;

///
/// A selectable I/O channel.
///
/// This class doesn't own the file descriptor.
/// The file descriptor could be a socket,
/// an eventfd, a timerfd, or a signalfd
class Channel : boost::noncopyable
{
 public:
  typedef boost::function<void()> EventCallback;
  typedef boost::function<void(Timestamp)> ReadEventCallback;

  Channel(EventLoop* loop, int fd);
  ~Channel();

  void handleEvent(Timestamp receiveTime);
  void setReadCallback(const ReadEventCallback& cb)
  { readCallback_ = cb; }
  void setWriteCallback(const EventCallback& cb)
  { writeCallback_ = cb; }
  void setCloseCallback(const EventCallback& cb)
  { closeCallback_ = cb; }
  void setErrorCallback(const EventCallback& cb)
  { errorCallback_ = cb; }

  /// Tie this channel to the owner object managed by shared_ptr,
  /// prevent the owner object being destroyed in handleEvent.
  void tie(const boost::shared_ptr<void>&);

  int fd() const { return fd_; }
  int events() const { return events_; }
  void set_revents(int revt) { revents_ = revt; } // used by pollers
  // int revents() const { return revents_; }
  bool isNoneEvent() const { return events_ == kNoneEvent; }

  void enableReading() { events_ |= kReadEvent; update(); }
  // void disableReading() { events_ &= ~kReadEvent; update(); }
  void enableWriting() { events_ |= kWriteEvent; update(); }
  void disableWriting() { events_ &= ~kWriteEvent; update(); }
  void disableAll() { events_ = kNoneEvent; update(); }
  bool isWriting() const { return events_ & kWriteEvent; }

  // for Poller
  int index() { return index_; }
  void set_index(int idx) { index_ = idx; }

  // for debug
  string reventsToString() const;

  void doNotLogHup() { logHup_ = false; }

  EventLoop* ownerLoop() { return loop_; }
  void remove();

 private:
  void update();
  void handleEventWithGuard(Timestamp receiveTime);

  static const int kNoneEvent;
  static const int kReadEvent;
  static const int kWriteEvent;

  EventLoop* loop_;			// 所属EventLoop
  const int  fd_;			// 文件描述符,但不负责关闭该文件描述符
  int        events_;		// 关注的事件
  int        revents_;		// poll/epoll返回的事件
  int        index_;		// used by Poller.表示在poll的事件数组中的序号
  bool       logHup_;		// for POLLHUP

  boost::weak_ptr<void> tie_;
  bool tied_;
  bool eventHandling_;		// 是否处于处理事件中
  ReadEventCallback readCallback_;
  EventCallback writeCallback_;
  EventCallback closeCallback_;
  EventCallback errorCallback_;
};

}
}
#endif  // MUDUO_NET_CHANNEL_H

Channel.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/base/Logging.h>
#include <muduo/net/Channel.h>
#include <muduo/net/EventLoop.h>

#include <sstream>

#include <poll.h>

using namespace muduo;
using namespace muduo::net;

const int Channel::kNoneEvent = 0;
const int Channel::kReadEvent = POLLIN | POLLPRI;
const int Channel::kWriteEvent = POLLOUT;

Channel::Channel(EventLoop* loop, int fd__)
  : loop_(loop),
    fd_(fd__),
    events_(0),
    revents_(0),
    index_(-1),
    logHup_(true),
    tied_(false),
    eventHandling_(false)
{
}

Channel::~Channel()
{
  assert(!eventHandling_);
}

void Channel::tie(const boost::shared_ptr<void>& obj)
{
  tie_ = obj;
  tied_ = true;
}

void Channel::update()
{
  loop_->updateChannel(this);
}

// 调用这个函数之前确保调用disableAll
void Channel::remove()
{
  assert(isNoneEvent());
  loop_->removeChannel(this);
}

void Channel::handleEvent(Timestamp receiveTime)
{
  boost::shared_ptr<void> guard;
  if (tied_)
  {
    guard = tie_.lock();
    if (guard)
    {
      handleEventWithGuard(receiveTime);
    }
  }
  else
  {
    handleEventWithGuard(receiveTime);
  }
}

void Channel::handleEventWithGuard(Timestamp receiveTime)
{
  eventHandling_ = true;
  if ((revents_ & POLLHUP) && !(revents_ & POLLIN))
  {
    if (logHup_)
    {
      LOG_WARN << "Channel::handle_event() POLLHUP";
    }
    if (closeCallback_) closeCallback_();
  }

  if (revents_ & POLLNVAL)
  {
    LOG_WARN << "Channel::handle_event() POLLNVAL";
  }

  if (revents_ & (POLLERR | POLLNVAL))
  {
    if (errorCallback_) errorCallback_();
  }
  if (revents_ & (POLLIN | POLLPRI | POLLRDHUP))
  {
    if (readCallback_) readCallback_(receiveTime);
  }
  if (revents_ & POLLOUT)
  {
    if (writeCallback_) writeCallback_();
  }
  eventHandling_ = false;
}

string Channel::reventsToString() const
{
  std::ostringstream oss;
  oss << fd_ << ": ";
  if (revents_ & POLLIN)
    oss << "IN ";
  if (revents_ & POLLPRI)
    oss << "PRI ";
  if (revents_ & POLLOUT)
    oss << "OUT ";
  if (revents_ & POLLHUP)
    oss << "HUP ";
  if (revents_ & POLLRDHUP)
    oss << "RDHUP ";
  if (revents_ & POLLERR)
    oss << "ERR ";
  if (revents_ & POLLNVAL)
    oss << "NVAL ";

  return oss.str().c_str();
}

Poller.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_POLLER_H
#define MUDUO_NET_POLLER_H

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

#include <muduo/base/Timestamp.h>
#include <muduo/net/EventLoop.h>

namespace muduo
{
namespace net
{

class Channel;

///
/// Base class for IO Multiplexing
///
/// This class doesn't own the Channel objects.
class Poller : boost::noncopyable
{
 public:
  typedef std::vector<Channel*> ChannelList;

  Poller(EventLoop* loop);
  virtual ~Poller();

  /// Polls the I/O events.
  /// Must be called in the loop thread.
  virtual Timestamp poll(int timeoutMs, ChannelList* activeChannels) = 0;

  /// Changes the interested I/O events.
  /// Must be called in the loop thread.
  virtual void updateChannel(Channel* channel) = 0;

  /// Remove the channel, when it destructs.
  /// Must be called in the loop thread.
  virtual void removeChannel(Channel* channel) = 0;

  static Poller* newDefaultPoller(EventLoop* loop);

  void assertInLoopThread()
  {
    ownerLoop_->assertInLoopThread();
  }

 private:
  EventLoop* ownerLoop_;	// Poller所属EventLoop
};

}
}
#endif  // MUDUO_NET_POLLER_H

Poller.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/Poller.h>

using namespace muduo;
using namespace muduo::net;

Poller::Poller(EventLoop* loop)
  : ownerLoop_(loop)
{
}

Poller::~Poller()
{
}


PollPoller.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_POLLER_POLLPOLLER_H
#define MUDUO_NET_POLLER_POLLPOLLER_H

#include <muduo/net/Poller.h>

#include <map>
#include <vector>

struct pollfd;

namespace muduo
{
namespace net
{

///
/// IO Multiplexing with poll(2).
///
class PollPoller : public Poller
{
 public:

  PollPoller(EventLoop* loop);
  virtual ~PollPoller();

  virtual Timestamp poll(int timeoutMs, ChannelList* activeChannels);
  virtual void updateChannel(Channel* channel);
  virtual void removeChannel(Channel* channel);

 private:
  void fillActiveChannels(int numEvents,
                          ChannelList* activeChannels) const;

  typedef std::vector<struct pollfd> PollFdList;
  typedef std::map<int, Channel*> ChannelMap;	// key是文件描述符,value是Channel*
  PollFdList pollfds_;
  ChannelMap channels_;
};

}
}
#endif  // MUDUO_NET_POLLER_POLLPOLLER_H

PollPoller.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/poller/PollPoller.h>

#include <muduo/base/Logging.h>
#include <muduo/base/Types.h>
#include <muduo/net/Channel.h>

#include <assert.h>
#include <poll.h>

using namespace muduo;
using namespace muduo::net;

PollPoller::PollPoller(EventLoop* loop)
  : Poller(loop)
{
}

PollPoller::~PollPoller()
{
}

Timestamp PollPoller::poll(int timeoutMs, ChannelList* activeChannels)
{
  // XXX pollfds_ shouldn't change
  int numEvents = ::poll(&*pollfds_.begin(), pollfds_.size(), timeoutMs);
  Timestamp now(Timestamp::now());
  if (numEvents > 0)
  {
    LOG_TRACE << numEvents << " events happended";
    fillActiveChannels(numEvents, activeChannels);
  }
  else if (numEvents == 0)
  {
    LOG_TRACE << " nothing happended";
  }
  else
  {
    LOG_SYSERR << "PollPoller::poll()";
  }
  return now;
}

void PollPoller::fillActiveChannels(int numEvents,
                                    ChannelList* activeChannels) const
{
  for (PollFdList::const_iterator pfd = pollfds_.begin();
      pfd != pollfds_.end() && numEvents > 0; ++pfd)
  {
    if (pfd->revents > 0)
    {
      --numEvents;
      ChannelMap::const_iterator ch = channels_.find(pfd->fd);
      assert(ch != channels_.end());
      Channel* channel = ch->second;
      assert(channel->fd() == pfd->fd);
      channel->set_revents(pfd->revents);
      // pfd->revents = 0;
      activeChannels->push_back(channel);
    }
  }
}

void PollPoller::updateChannel(Channel* channel)
{
  Poller::assertInLoopThread();
  LOG_TRACE << "fd = " << channel->fd() << " events = " << channel->events();
  if (channel->index() < 0)
  {
	// index < 0说明是一个新的通道
    // a new one, add to pollfds_
    assert(channels_.find(channel->fd()) == channels_.end());
    struct pollfd pfd;
    pfd.fd = channel->fd();
    pfd.events = static_cast<short>(channel->events());
    pfd.revents = 0;
    pollfds_.push_back(pfd);
    int idx = static_cast<int>(pollfds_.size())-1;
    channel->set_index(idx);
    channels_[pfd.fd] = channel;
  }
  else
  {
    // update existing one
    assert(channels_.find(channel->fd()) != channels_.end());
    assert(channels_[channel->fd()] == channel);
    int idx = channel->index();
    assert(0 <= idx && idx < static_cast<int>(pollfds_.size()));
    struct pollfd& pfd = pollfds_[idx];
    assert(pfd.fd == channel->fd() || pfd.fd == -channel->fd()-1);
    pfd.events = static_cast<short>(channel->events());
    pfd.revents = 0;
	// 将一个通道暂时更改为不关注事件,但不从Poller中移除该通道
    if (channel->isNoneEvent())
    {
      // ignore this pollfd
	  // 暂时忽略该文件描述符的事件
	  // 这里pfd.fd 可以直接设置为-1
      pfd.fd = -channel->fd()-1;	// 这样子设置是为了removeChannel优化
    }
  }
}

void PollPoller::removeChannel(Channel* channel)
{
  Poller::assertInLoopThread();
  LOG_TRACE << "fd = " << channel->fd();
  assert(channels_.find(channel->fd()) != channels_.end());
  assert(channels_[channel->fd()] == channel);
  assert(channel->isNoneEvent());
  int idx = channel->index();
  assert(0 <= idx && idx < static_cast<int>(pollfds_.size()));
  const struct pollfd& pfd = pollfds_[idx]; (void)pfd;
  assert(pfd.fd == -channel->fd()-1 && pfd.events == channel->events());
  size_t n = channels_.erase(channel->fd());
  assert(n == 1); (void)n;
  if (implicit_cast<size_t>(idx) == pollfds_.size()-1)
  {
    pollfds_.pop_back();
  }
  else
  {
	// 这里移除的算法复杂度是O(1),将待删除元素与最后一个元素交换再pop_back
    int channelAtEnd = pollfds_.back().fd;
    iter_swap(pollfds_.begin()+idx, pollfds_.end()-1);
    if (channelAtEnd < 0)
    {
      channelAtEnd = -channelAtEnd-1;
    }
    channels_[channelAtEnd]->set_index(idx);
    pollfds_.pop_back();
  }
}