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