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; //随机选择一个线程，通过管道向其传递socket fd,,可以修改成循环分配，比较平均 if (server->m_CurrentThread >= server->m_ThreadCount) server->m_CurrentThread = 0; //int num = rand() % server->m_ThreadCount; int sendfd = server->m_Threads[server->m_CurrentThread].notifySendFd; write(sendfd, &fd, sizeof(evutil_socket_t)); server->m_CurrentThread++; } 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;
// lock obj class CSLock { public: CSLock() { Init(); }
void Init() { pthread_rwlockattr_init(&rwLockAttr); if (pthread_rwlock_init(&rwLock, &rwLockAttr)) { } }
CSLock(const CSLock &objParam) { Init(); }
const CSLock & operator = (const CSLock &obj) { return *this; }
~CSLock() { pthread_rwlock_destroy(&rwLock); pthread_rwlockattr_destroy(&rwLockAttr); }
bool GetReadLock() const { if (pthread_rwlock_rdlock((pthread_rwlock_t *)&rwLock)) { return false; }
return true; }
bool GetWriteLock() const { if (pthread_rwlock_wrlock((pthread_rwlock_t *)&rwLock)) { return false; }
return true; }
bool ReleaseLock() const { if (pthread_rwlock_unlock((pthread_rwlock_t *)&rwLock)) { return false; }
return true; }
private: pthread_rwlock_t rwLock; pthread_rwlockattr_t rwLockAttr; };
//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)
{
printf("ReadEvent call.\n"); int len = conn->GetReadBufferLen();
if (len > 0) { vector<char> vTempRead(len, 0); conn->CopyReadBuffer(vTempRead.data(), len); printf("Read data:%s \n", vTempRead.data()); } //conn->MoveBufferData(); const char *reply = "server reply to client"; conn->AddToWriteBuffer(reply, strlen(reply));
}
void TestServer::WriteEvent(Conn *conn)
{
int len = conn->GetWriteBufferLen();
if (len > 0) { vector<char> vTempRead(len, 0); conn->CopyWriteBuffer(vTempRead.data(), len); printf("Write data:%s \n", vTempRead.data()); } printf("WriteEvent call.\n");
}
void TestServer::ConnectionEvent(Conn *conn)
{
TestServer *me = (TestServer*)conn->GetThread()->tcpConnect; printf("new connection :%d \n", conn->GetFd()); m_rwlock.GetWriteLock(); me->m_vecconn.push_back(conn); m_rwlock.ReleaseLock();
}
void TestServer::CloseEvent(Conn *conn, short events)
{
printf("connection closed. :%d \n", conn->GetFd()); TestServer *me = (TestServer*)conn->GetThread()->tcpConnect; m_rwlock.GetWriteLock(); vector<Conn*>::iterator it = std::find(me->m_vecconn.begin(), me->m_vecconn.end(), conn); if (it != me->m_vecconn.end()) { me->m_vecconn.erase(it); } m_rwlock.ReleaseLock();
}
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
