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) { } 

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;    
}