libevent+多线程

libevent+多线程最近在看memcached的源码,觉得它那种libevent+多线程的服务器模型真的很不错,我将这个模型封装成一个C++类,根据我的简单测试,这个模型的效率真的很不错,欢迎大家试用。这个类的使用方法很简单(缺点是不太灵活),只要派生一个类,根据需要重写以下这几个虚函数就行了:如果大家有什么建议或

大家好,欢迎来到IT知识分享网。libevent+多线程"

最近在看memcached的源码,觉得它那种libevent+多线程的服务器模型真的很不错,我将这个模型封装成一个C++类,根据我的简单测试,这个模型的效率真的很不错,欢迎大家试用。

这个类的使用方法很简单(缺点是不太灵活),只要派生一个类,根据需要重写以下这几个虚函数就行了:

//新建连接成功后,会调用该函数
virtual void ConnectionEvent(Conn *conn) { } //读取完数据后,会调用该函数 virtual void ReadEvent(Conn *conn) { } //发送完成功后,会调用该函数(因为串包的问题,所以并不是每次发送完数据都会被调用) virtual void WriteEvent(Conn *conn) { } //断开连接(客户自动断开或异常断开)后,会调用该函数 virtual void CloseEvent(Conn *conn, short events) { } //发生致命错误(如果创建子线程失败等)后,会调用该函数 //该函数的默认操作是输出错误提示,终止程序 virtual void ErrorQuit(const char *str);

如果大家有什么建议或意见,欢迎给我发邮件:aa1080711@163.com

上代码:

头文件:TcpEventServer.h

//TcpEventServer.h
#ifndef TCPEVENTSERVER_H_ #define TCPEVENTSERVER_H_ #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #include <errno.h> #include <signal.h> #include <time.h> #include <pthread.h> #include <fcntl.h> #include <map> using std::map; #include <event.h> #include <event2/bufferevent.h> #include <event2/buffer.h> #include <event2/listener.h> #include <event2/util.h> #include <event2/event.h> class TcpEventServer; class Conn; class ConnQueue; struct LibeventThread; //这个类一个链表的结点类,结点里存储各个连接的信息, //并提供了读写数据的接口 class Conn {  //此类只能由TcpBaseServer创建,  //并由ConnQueue类管理  friend class ConnQueue;  friend class TcpEventServer; private:  const int m_fd; //socket的ID  evbuffer *m_ReadBuf; //读数据的缓冲区  evbuffer *m_WriteBuf; //写数据的缓冲区  Conn *m_Prev; //前一个结点的指针  Conn *m_Next; //后一个结点的指针  LibeventThread *m_Thread;  Conn(int fd=0);  ~Conn(); public:  LibeventThread *GetThread() { return m_Thread; }  int GetFd() { return m_fd; }  //获取可读数据的长度  int GetReadBufferLen()  { return evbuffer_get_length(m_ReadBuf); }  //从读缓冲区中取出len个字节的数据,存入buffer中,若不够,则读出所有数据  //返回读出数据的字节数  int GetReadBuffer(char *buffer, int len)  { return evbuffer_remove(m_ReadBuf, buffer, len); }  //从读缓冲区中复制出len个字节的数据,存入buffer中,若不够,则复制出所有数据  //返回复制出数据的字节数  //执行该操作后,数据还会留在缓冲区中,buffer中的数据只是原数据的副本  int CopyReadBuffer(char *buffer, int len)  { return evbuffer_copyout(m_ReadBuf, buffer, len); }  //获取可写数据的长度  int GetWriteBufferLen()  { return evbuffer_get_length(m_WriteBuf); }  //将数据加入写缓冲区,准备发送  int AddToWriteBuffer(char *buffer, int len)  { return evbuffer_add(m_WriteBuf, buffer, len); }  //将读缓冲区中的数据移动到写缓冲区  void MoveBufferData()  { evbuffer_add_buffer(m_WriteBuf, m_ReadBuf); } }; //带头尾结点的双链表类,每个结点存储一个连接的数据 class ConnQueue { private:  Conn *m_head;  Conn *m_tail; public:  ConnQueue();  ~ConnQueue();  Conn *InsertConn(int fd, LibeventThread *t);  void DeleteConn(Conn *c);  //void PrintQueue(); }; //每个子线程的线程信息 struct LibeventThread {  pthread_t tid; //线程的ID  struct event_base *base; //libevent的事件处理机  struct event notifyEvent; //监听管理的事件机  int notifyReceiveFd; //管理的接收端  int notifySendFd; //管道的发送端  ConnQueue connectQueue; //socket连接的链表  //在libevent的事件处理中要用到很多回调函数,不能使用类隐含的this指针  //所以用这样方式将TcpBaseServer的类指针传过去  TcpEventServer *tcpConnect; //TcpBaseServer类的指针 }; class TcpEventServer { private:  int m_ThreadCount; //子线程数  int m_Port; //监听的端口  LibeventThread *m_MainBase; //主线程的libevent事件处理机  LibeventThread *m_Threads; //存储各个子线程信息的数组  map<int, event*> m_SignalEvents; //自定义的信号处理 public:  static const int EXIT_CODE = -1; private:  //初始化子线程的数据  void SetupThread(LibeventThread *thread);  //子线程的入门函数  static void *WorkerLibevent(void *arg);  //(主线程收到请求后),对应子线程的处理函数  static void ThreadProcess(int fd, short which, void *arg);  //被libevent回调的各个静态函数  static void ListenerEventCb(evconnlistener *listener, evutil_socket_t fd,   sockaddr *sa, int socklen, void *user_data);  static void ReadEventCb(struct bufferevent *bev, void *data);  static void WriteEventCb(struct bufferevent *bev, void *data);  static void CloseEventCb(struct bufferevent *bev, short events, void *data); protected:  //这五个虚函数,一般是要被子类继承,并在其中处理具体业务的  //新建连接成功后,会调用该函数  virtual void ConnectionEvent(Conn *conn) { }  //读取完数据后,会调用该函数  virtual void ReadEvent(Conn *conn) { }  //发送完成功后,会调用该函数(因为串包的问题,所以并不是每次发送完数据都会被调用)  virtual void WriteEvent(Conn *conn) { }  //断开连接(客户自动断开或异常断开)后,会调用该函数  virtual void CloseEvent(Conn *conn, short events) { }  //发生致命错误(如果创建子线程失败等)后,会调用该函数  //该函数的默认操作是输出错误提示,终止程序  virtual void ErrorQuit(const char *str); public:  TcpEventServer(int count);  ~TcpEventServer();  //设置监听的端口号,如果不需要监听,请将其设置为EXIT_CODE  void SetPort(int port)  { m_Port = port; }  //开始事件循环  bool StartRun();  //在tv时间里结束事件循环  //否tv为空,则立即停止  void StopRun(timeval *tv);  //添加和删除信号处理事件  //sig是信号,ptr为要回调的函数  bool AddSignalEvent(int sig, void (*ptr)(int, short, void*));  bool DeleteSignalEvent(int sig);  //添加和删除定时事件  //ptr为要回调的函数,tv是间隔时间,once决定是否只执行一次  event *AddTimerEvent(void(*ptr)(int, short, void*),   timeval tv, bool once);  bool DeleteTImerEvent(event *ev); }; #endif

 

实现文件:TcpEventServer.cpp

//TcpEventServer.cpp
#include "TcpEventServer.h" Conn::Conn(int fd) : m_fd(fd) {  m_Prev = NULL;  m_Next = NULL; } Conn::~Conn() { } ConnQueue::ConnQueue() {  //建立头尾结点,并调整其指针  m_head = new Conn(0);  m_tail = new Conn(0);  m_head->m_Prev = m_tail->m_Next = NULL;  m_head->m_Next = m_tail;  m_tail->m_Prev = m_head; } ConnQueue::~ConnQueue() {  Conn *tcur, *tnext;  tcur = m_head;  //循环删除链表中的各个结点  while( tcur != NULL )  {   tnext = tcur->m_Next;   delete tcur;   tcur = tnext;  } } Conn *ConnQueue::InsertConn(int fd, LibeventThread *t) {  Conn *c = new Conn(fd);  c->m_Thread = t;  Conn *next = m_head->m_Next;  c->m_Prev = m_head;  c->m_Next = m_head->m_Next;  m_head->m_Next = c;  next->m_Prev = c;  return c; } void ConnQueue::DeleteConn(Conn *c) {  c->m_Prev->m_Next = c->m_Next;  c->m_Next->m_Prev = c->m_Prev;  delete c; } /* void ConnQueue::PrintQueue() {  Conn *cur = m_head->m_Next;  while( cur->m_Next != NULL )  {   printf("%d ", cur->m_fd);   cur = cur->m_Next;  }  printf("\n"); } */ TcpEventServer::TcpEventServer(int count) {  //初始化各项数据  m_ThreadCount = count;  m_Port = -1;  m_MainBase = new LibeventThread;  m_Threads = new LibeventThread[m_ThreadCount];  m_MainBase->tid = pthread_self();  m_MainBase->base = event_base_new();  //初始化各个子线程的结构体  for(int i=0; i<m_ThreadCount; i++)  {   SetupThread(&m_Threads[i]);  } } TcpEventServer::~TcpEventServer() {  //停止事件循环(如果事件循环没开始,则没效果)  StopRun(NULL);  //释放内存  event_base_free(m_MainBase->base);  for(int i=0; i<m_ThreadCount; i++)   event_base_free(m_Threads[i].base);  delete m_MainBase;  delete [] m_Threads; } void TcpEventServer::ErrorQuit(const char *str) {  //输出错误信息,退出程序  fprintf(stderr, "%s", str);  if( errno != 0 )   fprintf(stderr, " : %s", strerror(errno));  fprintf(stderr, "\n");  exit(1); } void TcpEventServer::SetupThread(LibeventThread *me) {  //建立libevent事件处理机制  me->tcpConnect = this;  me->base = event_base_new();  if( NULL == me->base )   ErrorQuit("event base new error");  //在主线程和子线程之间建立管道  int fds[2];  if( pipe(fds) )   ErrorQuit("create pipe error");  me->notifyReceiveFd = fds[0];  me->notifySendFd = fds[1];  //让子线程的状态机监听管道  event_set( &me->notifyEvent, me->notifyReceiveFd,   EV_READ | EV_PERSIST, ThreadProcess, me );  event_base_set(me->base, &me->notifyEvent);  if ( event_add(&me->notifyEvent, 0) == -1 )   ErrorQuit("Can't monitor libevent notify pipe\n"); } void *TcpEventServer::WorkerLibevent(void *arg) {  //开启libevent的事件循环,准备处理业务  LibeventThread *me = (LibeventThread*)arg;  //printf("thread %u started\n", (unsigned int)me->tid);  event_base_dispatch(me->base);  //printf("subthread done\n"); } bool TcpEventServer::StartRun() {  evconnlistener *listener;  //如果端口号不是EXIT_CODE,就监听该端口号  if( m_Port != EXIT_CODE )  {   sockaddr_in sin;   memset(&sin, 0, sizeof(sin));   sin.sin_family = AF_INET;   sin.sin_port = htons(m_Port);   listener = evconnlistener_new_bind(m_MainBase->base,    ListenerEventCb, (void*)this,    LEV_OPT_REUSEABLE|LEV_OPT_CLOSE_ON_FREE, -1,    (sockaddr*)&sin, sizeof(sockaddr_in));   if( NULL == listener )    ErrorQuit("TCP listen error");  }  //开启各个子线程  for(int i=0; i<m_ThreadCount; i++)  {   pthread_create(&m_Threads[i].tid, NULL,    WorkerLibevent, (void*)&m_Threads[i]);  }  //开启主线程的事件循环  event_base_dispatch(m_MainBase->base);  //事件循环结果,释放监听者的内存  if( m_Port != EXIT_CODE )  {   //printf("free listen\n");   evconnlistener_free(listener);  } } void TcpEventServer::StopRun(timeval *tv) {  int contant = EXIT_CODE;  //向各个子线程的管理中写入EXIT_CODE,通知它们退出  for(int i=0; i<m_ThreadCount; i++)  {   write(m_Threads[i].notifySendFd, &contant, sizeof(int));  }  //结果主线程的事件循环  event_base_loopexit(m_MainBase->base, tv); } void TcpEventServer::ListenerEventCb(struct evconnlistener *listener,          evutil_socket_t fd,          struct sockaddr *sa,          int socklen,          void *user_data) {  TcpEventServer *server = (TcpEventServer*)user_data;  //随机选择一个子线程,通过管道向其传递socket描述符  int num = rand() % server->m_ThreadCount;  int sendfd = server->m_Threads[num].notifySendFd;  write(sendfd, &fd, sizeof(evutil_socket_t)); } void TcpEventServer::ThreadProcess(int fd, short which, void *arg) {  LibeventThread *me = (LibeventThread*)arg;  //从管道中读取数据(socket的描述符或操作码)  int pipefd = me->notifyReceiveFd;  evutil_socket_t confd;  read(pipefd, &confd, sizeof(evutil_socket_t));  //如果操作码是EXIT_CODE,则终于事件循环  if( EXIT_CODE == confd )  {   event_base_loopbreak(me->base);   return;  }  //新建连接  struct bufferevent *bev;  bev = bufferevent_socket_new(me->base, confd, BEV_OPT_CLOSE_ON_FREE);  if (!bev)  {   fprintf(stderr, "Error constructing bufferevent!");   event_base_loopbreak(me->base);   return;  }  //将该链接放入队列  Conn *conn = me->connectQueue.InsertConn(confd, me);  //准备从socket中读写数据  bufferevent_setcb(bev, ReadEventCb, WriteEventCb, CloseEventCb, conn);  bufferevent_enable(bev, EV_WRITE);  bufferevent_enable(bev, EV_READ);  //调用用户自定义的连接事件处理函数  me->tcpConnect->ConnectionEvent(conn); } void TcpEventServer::ReadEventCb(struct bufferevent *bev, void *data) {  Conn *conn = (Conn*)data;  conn->m_ReadBuf = bufferevent_get_input(bev);  conn->m_WriteBuf = bufferevent_get_output(bev);  //调用用户自定义的读取事件处理函数  conn->m_Thread->tcpConnect->ReadEvent(conn); } void TcpEventServer::WriteEventCb(struct bufferevent *bev, void *data) {  Conn *conn = (Conn*)data;  conn->m_ReadBuf = bufferevent_get_input(bev);  conn->m_WriteBuf = bufferevent_get_output(bev);  //调用用户自定义的写入事件处理函数  conn->m_Thread->tcpConnect->WriteEvent(conn); } void TcpEventServer::CloseEventCb(struct bufferevent *bev, short events, void *data) {  Conn *conn = (Conn*)data;  //调用用户自定义的断开事件处理函数  conn->m_Thread->tcpConnect->CloseEvent(conn, events);  conn->GetThread()->connectQueue.DeleteConn(conn);  bufferevent_free(bev); } bool TcpEventServer::AddSignalEvent(int sig, void (*ptr)(int, short, void*)) {  //新建一个信号事件  event *ev = evsignal_new(m_MainBase->base, sig, ptr, (void*)this);  if ( !ev ||   event_add(ev, NULL) < 0 )  {   event_del(ev);   return false;  }  //删除旧的信号事件(同一个信号只能有一个信号事件)  DeleteSignalEvent(sig);  m_SignalEvents[sig] = ev;  return true; } bool TcpEventServer::DeleteSignalEvent(int sig) {  map<int, event*>::iterator iter = m_SignalEvents.find(sig);  if( iter == m_SignalEvents.end() )   return false;  event_del(iter->second);  m_SignalEvents.erase(iter);  return true; } event *TcpEventServer::AddTimerEvent(void (*ptr)(int, short, void *),         timeval tv, bool once) {  int flag = 0;  if( !once )   flag = EV_PERSIST;  //新建定时器信号事件  event *ev = new event;  event_assign(ev, m_MainBase->base, -1, flag, ptr, (void*)this);  if( event_add(ev, &tv) < 0 )  {   event_del(ev);   return NULL;  }  return ev; } bool TcpEventServer::DeleteTImerEvent(event *ev) {  int res = event_del(ev);  return (0 == res); }

 

测试文件:test.cpp

/*
这是一个测试用的服务器,只有两个功能:
1:对于每个已连接客户端,每10秒向其发送一句hello, world
2:若客户端向服务器发送数据,服务器收到后,再将数据回发给客户端
*/
//test.cpp #include "TcpEventServer.h" #include <set> #include <vector> using namespace std; //测试示例 class TestServer : public TcpEventServer { private:  vector<Conn*> vec; protected:  //重载各个处理业务的虚函数  void ReadEvent(Conn *conn);  void WriteEvent(Conn *conn);  void ConnectionEvent(Conn *conn);  void CloseEvent(Conn *conn, short events); public:  TestServer(int count) : TcpEventServer(count) { }  ~TestServer() { }   //退出事件,响应Ctrl+C  static void QuitCb(int sig, short events, void *data);  //定时器事件,每10秒向所有客户端发一句hello, world  static void TimeOutCb(int id, int short events, void *data); }; void TestServer::ReadEvent(Conn *conn) {  conn->MoveBufferData(); } void TestServer::WriteEvent(Conn *conn) { } void TestServer::ConnectionEvent(Conn *conn) {  TestServer *me = (TestServer*)conn->GetThread()->tcpConnect;  printf("new connection: %d\n", conn->GetFd());  me->vec.push_back(conn); } void TestServer::CloseEvent(Conn *conn, short events) {  printf("connection closed: %d\n", conn->GetFd()); } void TestServer::QuitCb(int sig, short events, void *data) {  printf("Catch the SIGINT signal, quit in one second\n");  TestServer *me = (TestServer*)data;  timeval tv = {1, 0};  me->StopRun(&tv); } void TestServer::TimeOutCb(int id, short events, void *data) {  TestServer *me = (TestServer*)data;  char temp[33] = "hello, world\n";  for(int i=0; i<me->vec.size(); i++)   me->vec[i]->AddToWriteBuffer(temp, strlen(temp)); } int main() {  printf("pid: %d\n", getpid());  TestServer server(3);  server.AddSignalEvent(SIGINT, TestServer::QuitCb);  timeval tv = {10, 0};  server.AddTimerEvent(TestServer::TimeOutCb, tv, false);  server.SetPort(2111);  server.StartRun();  printf("done\n");   return 0; }

 

编译与运行命令:

qch@LinuxMint ~/program/ztemp $ g++ TcpEventServer.cpp test.cpp -o test -levent
qch@LinuxMint ~/program/ztemp $ ./test pid: 20264 new connection: 22 connection closed: 22 ^CCatch the SIGINT signal, quit in one second done

转自http://blog.csdn.net/cyblueboy83/article/details/38640375

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