SPServer源码分析（四）: 核心服务器类SP_Server分析

1。进入SP_Server的runForever函数，该函数最终转入start()函数执行

 

 

2。start函数是主要执行函数

函数内部使用了libevent.有关libevent编程参考官方主页。

 

函数内部涉及重要的类有：

SP_Executor（任务执行者，内部封装线程池）

 

 

/* * Copyright 2007 Stephen Liu * For license terms, see the file COPYING along with this library. */ #include <stdio.h> #include <string.h> #include <stdlib.h> #include <assert.h> #include <errno.h> #include <signal.h> #include "spserver.hpp" #include "speventcb.hpp" #include "sphandler.hpp" #include "spsession.hpp" #include "spexecutor.hpp" #include "sputils.hpp" #include "spiochannel.hpp" #include "spioutils.hpp" #include "event_msgqueue.h" SP_Server :: SP_Server( const char * bindIP, int port, SP_HandlerFactory * handlerFactory ) { snprintf( mBindIP, sizeof( mBindIP ), "%s", bindIP ); mPort = port; mIsShutdown = 0; mIsRunning = 0; mHandlerFactory = handlerFactory; mIOChannelFactory = NULL; mTimeout = 600; mMaxThreads = 4; mReqQueueSize = 128; mMaxConnections = 256; mRefusedMsg = strdup( "System busy, try again later." ); } SP_Server :: ~SP_Server() { if( NULL != mHandlerFactory ) delete mHandlerFactory; mHandlerFactory = NULL; if( NULL != mIOChannelFactory ) delete mIOChannelFactory; mIOChannelFactory = NULL; if( NULL != mRefusedMsg ) free( mRefusedMsg ); mRefusedMsg = NULL; } void SP_Server :: setIOChannelFactory( SP_IOChannelFactory * ioChannelFactory ) { mIOChannelFactory = ioChannelFactory; } void SP_Server :: setTimeout( int timeout ) { mTimeout = timeout > 0 ? timeout : mTimeout; } void SP_Server :: setMaxThreads( int maxThreads ) { mMaxThreads = maxThreads > 0 ? maxThreads : mMaxThreads; } void SP_Server :: setMaxConnections( int maxConnections ) { mMaxConnections = maxConnections > 0 ? maxConnections : mMaxConnections; } void SP_Server :: setReqQueueSize( int reqQueueSize, const char * refusedMsg ) { mReqQueueSize = reqQueueSize > 0 ? reqQueueSize : mReqQueueSize; if( NULL != mRefusedMsg ) free( mRefusedMsg ); mRefusedMsg = strdup( refusedMsg ); } void SP_Server :: shutdown() { mIsShutdown = 1; } int SP_Server :: isRunning() { return mIsRunning; } int SP_Server :: run() { int ret = -1; sp_thread_attr_t attr; sp_thread_attr_init( &attr ); assert( sp_thread_attr_setstacksize( &attr, 1024 * 1024 ) == 0 ); sp_thread_attr_setdetachstate( &attr, SP_THREAD_CREATE_DETACHED ); sp_thread_t thread; ret = sp_thread_create( &thread, &attr, eventLoop, this ); sp_thread_attr_destroy( &attr ); if( 0 == ret ) { sp_syslog( LOG_NOTICE, "Thread #%ld has been created to listen on port [%d]", thread, mPort ); } else { mIsRunning = 0; sp_syslog( LOG_WARNING, "Unable to create a thread for TCP server on port [%d], %s", mPort, strerror( errno ) ) ; } return ret; } void SP_Server :: runForever() { eventLoop( this ); } sp_thread_result_t SP_THREAD_CALL SP_Server :: eventLoop( void * arg ) { SP_Server * server = (SP_Server*)arg; server->mIsRunning = 1; server->start(); server->mIsRunning = 0; return 0; } void SP_Server :: sigHandler( int, short, void * arg ) { SP_Server * server = (SP_Server*)arg; server->shutdown(); } void SP_Server :: outputCompleted( void * arg ) { SP_CompletionHandler * handler = ( SP_CompletionHandler * ) ((void**)arg)[0]; SP_Message * msg = ( SP_Message * ) ((void**)arg)[ 1 ]; handler->completionMessage( msg ); free( arg ); } int SP_Server :: start() { #ifdef SIGPIPE /* Don't die with SIGPIPE on remote read shutdown. That's dumb. */ signal( SIGPIPE, SIG_IGN ); #endif int ret = 0; int listenFD = -1; ret = SP_IOUtils::tcpListen( mBindIP, mPort, &listenFD, 0 ); if( 0 == ret ) { SP_EventArg eventArg( mTimeout ); // Clean close on SIGINT or SIGTERM. struct event evSigInt, evSigTerm; signal_set( &evSigInt, SIGINT, sigHandler, this ); event_base_set( eventArg.getEventBase(), &evSigInt ); signal_add( &evSigInt, NULL); signal_set( &evSigTerm, SIGTERM, sigHandler, this ); event_base_set( eventArg.getEventBase(), &evSigTerm ); signal_add( &evSigTerm, NULL); SP_AcceptArg_t acceptArg; memset( &acceptArg, 0, sizeof( SP_AcceptArg_t ) ); if( NULL == mIOChannelFactory ) { mIOChannelFactory = new SP_DefaultIOChannelFactory(); } acceptArg.mEventArg = &eventArg; acceptArg.mHandlerFactory = mHandlerFactory; acceptArg.mIOChannelFactory = mIOChannelFactory; acceptArg.mReqQueueSize = mReqQueueSize; acceptArg.mMaxConnections = mMaxConnections; acceptArg.mRefusedMsg = mRefusedMsg; struct event evAccept; event_set( &evAccept, listenFD, EV_READ|EV_PERSIST, SP_EventCallback::onAccept, &acceptArg ); event_base_set( eventArg.getEventBase(), &evAccept ); event_add( &evAccept, NULL ); SP_Executor workerExecutor( mMaxThreads, "work" ); SP_Executor actExecutor( 1, "act" ); SP_CompletionHandler * completionHandler = mHandlerFactory->createCompletionHandler(); /* Start the event loop. */ while( 0 == mIsShutdown ) { event_base_loop( eventArg.getEventBase(), EVLOOP_ONCE ); for( ; NULL != eventArg.getInputResultQueue()->top(); ) { SP_Task * task = (SP_Task*)eventArg.getInputResultQueue()->pop(); workerExecutor.execute( task ); } for( ; NULL != eventArg.getOutputResultQueue()->top(); ) { SP_Message * msg = (SP_Message*)eventArg.getOutputResultQueue()->pop(); void ** arg = ( void** )malloc( sizeof( void * ) * 2 ); arg[ 0 ] = (void*)completionHandler; arg[ 1 ] = (void*)msg; actExecutor.execute( outputCompleted, arg ); } } delete completionHandler; sp_syslog( LOG_NOTICE, "Server is shutdown." ); event_del( &evAccept ); signal_del( &evSigTerm ); signal_del( &evSigInt ); sp_close( listenFD ); } return ret; }

 

L160初始化服务器监听，188-192初始化事件，194初始化任务执行者workerExecutor

 

这里使用了半同步、半异步模式。

 

event_base_loop( eventArg.getEventBase(), EVLOOP_ONCE );运行在主线程当中，借助libevent的抓取TCP异步事件。

 

class SP_EventCallback {
public:
 static void onAccept( int fd, short events, void * arg ); //处理客户端连接事件
 static void onRead( int fd, short events, void * arg );   //处理客户端读数据事件
 static void onWrite( int fd, short events, void * arg );  //处理客户端写数据事件

 static void onResponse( void * queueData, void * arg );

 static void addEvent( SP_Session * session, short events, int fd );

...}

 

SP_EventCallback处理各种事件，将对应的后续处理函数入队。由任务执行者对象出队，交给线程池去执行。

 

class SP_EventHelper {
public:
 static void doStart( SP_Session * session ); //对应onAccept事件
 static void start( void * arg );

 static void doError( SP_Session * session ); //对应onRead和onWrite中的错误处理流程
 static void error( void * arg );

 static void doTimeout( SP_Session * session ); //对应onRead和onWrite中的超时处理流程
 static void timeout( void * arg );

 static void doClose( SP_Session * session ); //对应onWrite的正常关闭处理流程
 static void myclose( void * arg );

 static void doCompletion( SP_EventArg * eventArg, SP_Message * msg ); //对应onResponse中的完成处理流程

...

}

 

该类当中doXXX函数最用是配合事件处理函数将XXX函数入队。XXX函数是由线程去真正地执行