multi-reactor服务器模型的C++封装类（libevent+多线程实现）

最近在看memcached的源码，觉得它那种libevent+多线程的服务器模型(multi-reactor)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) { }

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：MultiServer.h

//MultiServer.h
#ifndef MULTISERVER_H_
#define MULTISERVER_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 <assert.h>
#include <event.h>
#include <event2/bufferevent.h>
#include <event2/buffer.h>
#include <event2/listener.h>
#include <event2/util.h>
#include <event2/event.h>
class MultiServer;
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 MultiServer;
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
MultiServer *tcpConnect; //TcpBaseServer类的指针
};
class MultiServer
{
private:
static const int EXIT_CODE = -1;
static const int MAX_SIGNAL = 256;
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
event *m_SignalEvents[MAX_SIGNAL]; //自定义的信号处理
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) { }
public:
MultiServer(int count);
~MultiServer();
//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：MulitServer.cpp

//MultiServer.cpp
#include "MultiServer.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");
}
*/
MultiServer::MultiServer(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();
memset(m_SignalEvents, 0, sizeof(m_SignalEvents));
//初始化各个子线程的结构体
for(int i=0; i<m_ThreadCount; i++)
{
SetupThread(&m_Threads[i]);
}
}
MultiServer::~MultiServer()
{
//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 MultiServer::SetupThread(LibeventThread *me)
{
int res;
//建立libevent事件处理机制
me->tcpConnect = this;
me->base = event_base_new();
assert( me->base != NULL );
//在主线程和子线程之间建立管道
int fds[2];
res = pipe(fds);
assert( res == 0 );
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);
res = event_add(&me->notifyEvent, 0);
assert( res == 0 );
}
void *MultiServer::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 MultiServer::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 )
{
fprintf(stderr, "listen error: %s\n", strerror(errno));
exit(1);
}
}
//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 MultiServer::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 MultiServer::ListenerEventCb(struct evconnlistener *listener,
evutil_socket_t fd,
struct sockaddr *sa,
int socklen,
void *user_data)
{
MultiServer *server = (MultiServer*)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 MultiServer::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 MultiServer::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 MultiServer::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 MultiServer::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 MultiServer::AddSignalEvent(int sig, void (*ptr)(int, short, void*))
{
if( sig >= MAX_SIGNAL )
return false;
//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）
if( NULL != m_SignalEvents[sig] )
DeleteSignalEvent(sig);
m_SignalEvents[sig] = ev;
return true;
}
bool MultiServer::DeleteSignalEvent(int sig)
{
event *ev = m_SignalEvents[sig];
if( sig >= MAX_SIGNAL || NULL == ev )
return false;
event_del(ev);
ev = NULL;
return true;
}
event *MultiServer::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 MultiServer::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 "MultiServer.h"
#include <set>
#include <vector>
using namespace std;
//测试示例
class TestServer : public MultiServer
{
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) : MultiServer(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

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multi-reactor服务器模型的C++封装类（libevent+多线程实现）

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