分享一个延时加载的封装代码

来源：互联网发布：ss24二极管数据手册编辑：程序博客网时间：2024/06/11 01:32

// delayloader.cpp : 定义控制台应用程序的入口点。//#include "stdafx.h"#include <iostream>#include <cassert>using namespace std;#include <boost/function.hpp>#include <boost/bind.hpp>template <class Wapper_Type>class DelayLoader{private:DelayLoader();DelayLoader(const DelayLoader<Wapper_Type> &);DelayLoader<DelayLoader > & operator =(const DelayLoader<Wapper_Type> & );public:explicit DelayLoader( boost::function<bool ( Wapper_Type *&  ) > loader ): loader_(loader ), data_(NULL), init_(false) {}~DelayLoader() {if (data_ != NULL){delete data_;data_ = NULL;}}Wapper_Type & operator*(){return *Get();}Wapper_Type * operator->(){return Get();}Wapper_Type * Get(){if (init_ == false){data_ = new Wapper_Type;if (data_ == NULL){throw std::runtime_error("ASSERT(data_ == NULL)");}else if ( loader_(data_) == false ){delete data_;data_ = NULL;throw std::runtime_error("ASSERT(loader_(data_) == false)");}init_ = true;}return data_;}void Clear(){delete data_;data_ = NULL;init_ = false;}void Reload(){if (init_ == true){Wapper_Type * data = new Wapper_Type;if (data == NULL){throw std::runtime_error("ASSERT(data == NULL)");}else if ( loader_(data) == false ){delete data;data = NULL;throw std::runtime_error("ASSERT(loader_(data) == false)");}delete data_;data_ = data;}}private:boost::function<bool ( Wapper_Type *&  ) > loader_;Wapper_Type * data_;bool init_;};bool readcfg(int mid, int * gold){if (mid == 0){*gold = 1;}else{*gold = 2;}return true;}bool readcfg(int mid, const string & pw, int * gold){if (pw.empty() && mid == 0){*gold = 3;}else{*gold = 4;}return true;}class point{public:int x_;int y_;};bool readpoint(point * p){p->x_ = 1;p->y_ = 2;return true;}bool readpoint_false(point * p){return false;}int _tmain(int argc, _TCHAR* argv[]){DelayLoader<int > int_0(boost::bind( readcfg, 0, _1)  );cout<<*int_0<<endl;DelayLoader<int > int_1(boost::bind( readcfg, 1, "passwd", _1)  );cout<<*int_1<<endl;DelayLoader<point > pint_1(boost::bind( readpoint, _1)  );cout<<"x_:="<<pint_1->x_<<", y_:="<<pint_1->y_<<endl;{DelayLoader<point > pint_1(boost::bind( readpoint_false, _1)  );assert(pint_1.Get() == NULL);assert(pint_1.Get() == NULL);}return 0;}

在游戏服务器端编程时，常发现有些玩家数据可以延时加载，即：需要用的时候，再加载，于是，写了这个一个包装类。。。

请各位大侠指正！