Proactor和Reactor模式_继续并发系统设计的扫盲

Proactor和Reactor模式_继续并发系统设计的扫盲

6.6.2008

Kevin Lynx

Proactor和Reactor都是并发编程中的设计模式。在我看来，他们都是用于派发/分离IO操作事件的。这里所谓的
IO事件也就是诸如read/write的IO操作。"派发/分离"就是将单独的IO事件通知到上层模块。两个模式不同的地方
在于，Proactor用于异步IO，而Reactor用于同步IO。

摘抄一些关键的东西：

"
Two>///
classhandler
{
public:
virtualvoidonRead()=0;
virtualvoidonWrite()=0;
virtualvoidonAccept()=0;
};

classdispatch
{
public:
voidpoll()
{
//addfdintheset.
//
//polleveryfd
intc=select(0,&read_fd,&write_fd,0);
if(c>0)
{
foreachfdintheread_fd_set
{iffdcanread
_handler->onRead();
iffdcanaccept
_handler->onAccept();
}

foreachfdinthewrite_fd_set
{
iffdcanwrite
_handler->onWrite();
}
}
}

voidsetHandler(handler*_h)
{
_handler=_h;
}

private:
handler*_handler;
};

///application
classMyHandler:publichandler
{
public:
voidonRead()
{
}

voidonWrite()
{
}

voidonAccept()
{
}
};

classAsyIOProcessor
{
public:
voiddo_read()
{
//sendreadoperationtoOS
//readiofinished.anddispatchnotification
_proactor->dispatch_read();
}

private:
Proactor*_proactor;
};

classProactor
{
public:
voiddispatch_read()
{
_handlerMgr->onRead();
}

private:
HandlerManager*_handlerMgr;
};

classHandlerManager
{
public:
typedefstd::list<Handler*>HandlerList;

public:
voidonRead()
{
//notifyallthehandlers.
std::for_each(_handlers.begin(),_handlers.end(),onRead);
}

private:
HandlerList*_handlers;
};

classHandler
{
public:
virtualvoidonRead()=0;
};

// applicationlevelhandler.
classMyHandler: publicHandler
{
public:
voidonRead()
{
//
}
};