对libevent+多线程服务器模型的C++封装类

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：[e-mail]

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, world2：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 -leventqch@LinuxMint ~/program/ztemp $ ./testpid: 20264new connection: 22connection closed: 22^CCatch the SIGINT signal, quit in one seconddone