// 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 <boost/noncopyable.hpp>#include <muduo/base/CurrentThread.h>
#include <muduo/base/Thread.h>namespace muduo
{
namespace net
{///
/// 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 assertInLoopThread(){if (!isInLoopThread()){abortNotInLoopThread();}}bool isInLoopThread() const { return threadId_ == CurrentThread::tid(); }static EventLoop* getEventLoopOfCurrentThread();private:void abortNotInLoopThread();bool looping_; /* atomic */const pid_t threadId_;     // 当前对象所属线程ID
};}
}
#endif  // MUDUO_NET_EVENTLOOP_H

EventLoop.c

// 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 <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;
}EventLoop* EventLoop::getEventLoopOfCurrentThread()
{return t_loopInThisThread;
}EventLoop::EventLoop(): looping_(false),threadId_(CurrentThread::tid())
{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);LOG_TRACE << "EventLoop " << this << " stop looping";looping_ = false;
}void EventLoop::abortNotInLoopThread()
{LOG_FATAL << "EventLoop::abortNotInLoopThread - EventLoop " << this<< " was created in threadId_ = " << threadId_<< ", current thread id = " <<  CurrentThread::tid();
}

Reactor_test01.cc

#include <muduo/net/EventLoop.h>#include <stdio.h>using namespace muduo;
using namespace muduo::net;void threadFunc()
{printf("threadFunc(): pid = %d, tid = %d\n",getpid(), CurrentThread::tid());EventLoop loop;loop.loop();
}int main(void)
{printf("main(): pid = %d, tid = %d\n",getpid(), CurrentThread::tid());EventLoop loop;Thread t(threadFunc);t.start();loop.loop();t.join();return 0;
}

Reactor_02.cc

#include <muduo/net/EventLoop.h>#include <stdio.h>using namespace muduo;
using namespace muduo::net;EventLoop* g_loop;void threadFunc()
{g_loop->loop();
}int main(void)
{EventLoop loop;g_loop = &loop;Thread t(threadFunc);t.start();t.join();return 0;
}

运行结果