C/C++轻量级并发TCP服务器框架Zinx-框架开发003:转大写字母输出+责任链模式+代码重构思路及实现

1 添加转大写字母输出功能

功能流程：

• stdin通道类中包含一个功能处理类对象
• 功能处理类中包含一个stdout类对象
• 数据被读取到stdin通道，stdin通道将其交给功能处理类对象，该对象判断数据特点后转大写或直接交个stdout类对象进行输出

class process_func {
public:
	void DataProc(string &_input)
	{
		string output = _input;
		transform(output.begin(), output.end(), output.begin(),::toupper);
		poOut->DataPush(output);
	}
} *poProcess = new process_func();

/

class stdin_channel :public Ichannel {
public:

	// 通过 Ichannel 继承
	virtual bool ReadFd(std::string & _input) override
	{
		cin >> _input;
		return true;
	}

	virtual bool WriteFd(std::string & _output) override
	{
		return false;
	}

	virtual int GetFd() override
	{
		return 0;
	}

	virtual bool DataProcess(std::string & _data) override
	{
		poProcess->DataProc(_data);
		return true;
	}
};

2 责任链模式

通道类和功能处理类的对象都是整个流程中的环节，将这些环节连起来则形成责任链。

处理者类设计：

• 提供handle函数作为链式处理的入口
• handle内部执行当前环节的处理，并执行下一阶段的处理函数，直到没有下一环节
• 提供internalhandle纯虚函数用来执行本环节处理
• 提供getnext纯虚函数用来获取下一环节

消息类设计：

• 只提供虚析构函数，用户可自行扩展

2.1 责任链的设计

/*责任链设计*/
class IZinxMsg {
public:
	IZinxMsg() {}
	virtual ~IZinxMsg() {}
};



class AZinxHandler {
public:
	AZinxHandler() {}
	virtual ~AZinxHandler() {}
	void Handle(IZinxMsg &_oInput);
protected:
	virtual IZinxMsg *InternelHandle(IZinxMsg &_oInput) = 0;
	virtual AZinxHandler *GetNextHandler(IZinxMsg &_oNextMsg) = 0;
};

2.2 责任链的实现

/*责任链实现*/
void AZinxHandler::Handle(IZinxMsg & _oInput)
{
	IZinxMsg *poNextMsg = NULL;
	AZinxHandler *poNextHandler = NULL;

	poNextMsg = InternelHandle(_oInput);
	if (NULL != poNextMsg)
	{
        /*下一个环节处理*/
		poNextHandler = GetNextHandler(*poNextMsg);
        
        /*有下一个环节才处理*/
		if (NULL != poNextHandler)
		{
			poNextHandler->Handle(*poNextMsg);
		}

		delete poNextMsg;
	}

	return;
}

2.3 责任链的测试

/*责任链测试：将一串字符串交给处理者1进行首字母大写并输出，然后转交给处理者2进行字符统计并输出*/
class str_msg :public IZinxMsg {
public:
	str_msg(string &_content):content(_content) {}
	string content;
};

class h2_Count :public AZinxHandler {
	// 通过 AZinxHandler 继承
	virtual IZinxMsg * InternelHandle(IZinxMsg & _oInput) override
	{
		auto input = dynamic_cast<str_msg&>(_oInput);
		cout << "处理者2处理开始" << endl;
		cout << input.content.size() << endl;
		cout << "处理者2处理结束" << endl;
		return NULL;
	}
	virtual AZinxHandler * GetNextHandler(IZinxMsg & _oNextMsg) override
	{
		return nullptr;
	}
} h2;

class h1_UpperFirst :public AZinxHandler {
	// 通过 AZinxHandler 继承
	virtual IZinxMsg * InternelHandle(IZinxMsg & _oInput) override
	{
		auto input = dynamic_cast<str_msg&>(_oInput);
		cout << "处理者1处理开始" << endl;
		str_msg *pret = new str_msg(input.content);
		auto head = pret->content.begin();
		transform(head, head+1, head, ::toupper);
		cout << pret->content << endl;
		cout << "处理者1处理结束" << endl;
		return pret;
	}
	virtual AZinxHandler * GetNextHandler(IZinxMsg & _oNextMsg) override
	{
		return &h2;
	}
} h1;

int main()
{
	string input = "hello";
	str_msg input_msg(input);
	h1.Handle(input_msg);
}

3 代码重构

3.1 类图设计

3.2 重构设计 - 头文件

重构通道类和功能处理类（继承handler类）：

• 通道类的data_process函数不要了，通过重写internelhandle实现
• 功能处理类的dataproc函数不要了，通过重写internelhandle实现
• stdin类通过重写getnext方法返回功能处理对象
• 功能处理类重写getnext方法返回stdout对象

重构kernel类：

• epoll中不再执行channel类的方法，替换成handler类的handle方法
• kernel类判断当前epoll的触发方向并将其封装为消息类对象传递给通道类
• kernel增加函数用来处理程序向外发送数据（取代直接调用通道类的sendout函数）

创建消息类（继承message类）：

• 创建IO方向类用来让epoll给channel对象传递当前ready的IO方向
• 创建byte消息类用来让channel对象给功能处理对象传递待处理字符串
• 逐级继承保证消息内容丰富性

/*重构类---设计*/

#define GET_REF2DATA(type, ref, orig)  type * pref = dynamic_cast<type *>(&orig); if (nullptr == pref) {return nullptr;} type &ref = dynamic_cast<type&>(orig)

class IZinxMsg {
public:
	IZinxMsg() {}
	virtual ~IZinxMsg() {}
};

class SysIOReadyMsg :public IZinxMsg {
public:
	enum IO_DIC {
		IN, OUT
	} m_emIoDic;

	SysIOReadyMsg(IO_DIC _dic) :m_emIoDic(_dic) {}
};

class BytesMsg :public SysIOReadyMsg {
public:
	BytesMsg(SysIOReadyMsg &_base) :SysIOReadyMsg(_base.m_emIoDic) {}
	std::string szData;
};

//

class AZinxHandler {
public:
	AZinxHandler() {}
	virtual ~AZinxHandler() {}
	void Handle(IZinxMsg &_oInput);
protected:
	virtual IZinxMsg *InternelHandle(IZinxMsg &_oInput) = 0;
	virtual AZinxHandler *GetNextHandler(IZinxMsg &_oNextMsg) = 0;
};


class Ichannel:public AZinxHandler {
public:
	virtual bool ReadFd(std::string &_input) = 0;
	virtual bool WriteFd(std::string &_output) = 0;
	virtual int GetFd() = 0;
	void DataSendOut();
	void DataPush(std::string &_data);
	std::list<std::string> m_write_buffer;

	virtual IZinxMsg * InternelHandle(IZinxMsg & _oInput) override;
};


class ZinxKernel {
	static void Zinx_SendOut(std::string &_output, Ichannel &_oChannel);
};

3.3 重构实现

/*重构实现*/
void ZinxKernel::Zinx_Run()
{
	int iEpollRet = -1;

	for(;;)
	{
		struct epoll_event atmpEvent[100];
		iEpollRet = epoll_wait(GetInstance()->iEpollFd, atmpEvent, 100, -1);
		if (-1 == iEpollRet)
		{
			if (EINTR == errno)
			{
				continue;
			}
			else
			{
				break;
			}
		}
		for (int i = 0; i < iEpollRet; i++)
		{
			Ichannel *poChannel = static_cast<Ichannel *>(atmpEvent[i].data.ptr);
			if (0 != (EPOLLIN & atmpEvent[i].events))
			{
				string input;
				SysIOReadyMsg IoStat = SysIOReadyMsg(SysIOReadyMsg::IN);
				poChannel->Handle(IoStat);
			}
			if (0 != (EPOLLOUT & atmpEvent[i].events))
			{
				poChannel->DataSendOut();
				if (poChannel->m_write_buffer.empty())
				{
					Zinx_ClearChannelOut(*poChannel);
				}
			}
		}
	}
}


void ZinxKernel::Zinx_SendOut(std::string & _output, Ichannel & _oChannel)
{
	SysIOReadyMsg iodic = SysIOReadyMsg(SysIOReadyMsg::OUT);
	BytesMsg oBytes = BytesMsg(iodic);
	oBytes.szData = _output;
	_oChannel.Handle(oBytes);
}


IZinxMsg * Ichannel::InternelHandle(IZinxMsg & _oInput)
{
	IZinxMsg *poRet = NULL;
	GET_REF2DATA(SysIOReadyMsg, oIoStat, _oInput);
	if (oIoStat.m_emIoDic == SysIOReadyMsg::IN)
	{
		BytesMsg *poBytes = new BytesMsg(oIoStat);
		if (true == ReadFd(poBytes->szData))
		{
			poRet = poBytes;
		}
		else
		{
			delete poBytes;
		}
	}
	else if (oIoStat.m_emIoDic == SysIOReadyMsg::OUT)
	{
		GET_REF2DATA(BytesMsg, oBytes, _oInput);
		if (true == m_write_buffer.empty())
		{
			ZinxKernel::Zinx_SetChannelOut(*this);
		}
		m_write_buffer.push_back(oBytes.szData);
	}

	return poRet;
}

/*重构后测试*/
#include "Zinx.h"
#include <algorithm>
using namespace std;

class stdout_channel :public Ichannel {
public:
	virtual bool ReadFd(std::string & _input) override
	{
		return false;
	}
	virtual bool WriteFd(std::string & _output) override
	{
		cout << _output << endl;
		return true;
	}
	virtual int GetFd() override
	{
		return 1;
	}
	virtual AZinxHandler * GetNextHandler(IZinxMsg & _oNextMsg) override
	{
		return nullptr;
	}

} *poOut = new stdout_channel();

class process_func :public AZinxHandler{
public:
	void DataProc(string &_input)
	{
		string output = _input;
		transform(output.begin(), output.end(), output.begin(),::toupper);
		poOut->DataPush(output);
	}
	virtual IZinxMsg * InternelHandle(IZinxMsg & _oInput) override
	{
		GET_REF2DATA(BytesMsg, input, _oInput);
		string output = input.szData;
		transform(output.begin(), output.end(), output.begin(), ::toupper);
		ZinxKernel::Zinx_SendOut(output, *poOut);
		return NULL;
	}
	virtual AZinxHandler * GetNextHandler(IZinxMsg & _oNextMsg) override
	{
		return nullptr;
	}
} *poProcess = new process_func();

class stdin_channel :public Ichannel {
public:
	virtual bool ReadFd(std::string & _input) override
	{
		cin >> _input;
		return true;
	}

	virtual bool WriteFd(std::string & _output) override
	{
		return false;
	}

	virtual int GetFd() override
	{
		return 0;
	}
	virtual AZinxHandler * GetNextHandler(IZinxMsg & _oNextMsg) override
	{
		return poProcess;
	}

};

int main()
{
	ZinxKernel::ZinxKernelInit();
	ZinxKernel::Zinx_Add_Channel(*(new stdin_channel()));
	ZinxKernel::Zinx_Add_Channel(*poOut);
	ZinxKernel::Zinx_Run();
	ZinxKernel::ZinxKernelFini();
}