工具类库系列(十一)-ObjectMap

第十一个工具类：ObjectMap

ObjectMap 是一个上篇提到的 objectid64 的一个id<->id映射关系表，由map实现

该类用于需求中时常会出现的 1对1  或者 1对多 映射关系，

比如：

1对1：一个网络链接对象 对应 一个玩家数据对象， 一个玩家数据对象 也对应一个 网络链接对象

1对多：一个玩家对象 对应 一个游戏公会对象

同时：

1、继承boost::noncopyable，禁止ObjectMap对象间拷贝赋值

2、ObjectMap加了锁，确保操作是线程安全了

3、实现了当一个线程在对ObjectMap进行迭代，其他线程在对ObjectMap进行添加/删除，确保迭代不失效

如何实现保证迭代不失效：

ObjectMap中保存了迭代时当前的迭代器std::map::iterator对象

当做删除操作时，先检查下要删除的这个对象是否就是当前正在遍历的那个对象

是的话，则保存的迭代器后移，再删除

提供的主要接口：

1、增加一个id<->id的映射关系：void AddObject(objectid64 key, objectid64 value);

2、查找一个id<->id映射关系（没找到返回NULL_ID）：objectid64 FindObject(objectid64 key);

3、判断一个id<->id映射关系是否存在：bool IsExistsObject(objectid64 key);

4、删除一个id<->id映射关系：void FreeObject(objectid64 key);

5、获取id<->id映射关系的数量：unsigned int GetSize();

6、迭代：objectid64 BeginObject();  objectid64 NextObject();

上代码：

ObjectMap.h

#ifndef __ObjectMap_h__#define __ObjectMap_h__#include <boost/noncopyable.hpp>#include <map>#include "ToolDefine.h"namespace common{namespace tool{// 纯uint64的键值对池// 主要用于id对id的索引class ObjectMap : private boost::noncopyable{public:ObjectMap();~ObjectMap();// 使用一个空闲结点void AddObject(objectid64 key, objectid64 value);// 随机一个结点（分配第一个结点，空列表返回空）objectid64 RandObject();// 查找一个结点（没找到返回空）objectid64 FindObject(objectid64 key);bool IsExistsObject(objectid64 key);// 释放一个结点void FreeObject(objectid64 key);// 获取对象个数unsigned int GetSize();// 迭代objectid64 BeginObject();objectid64 NextObject();private:rw_mutex m_object_list_lock;typedef std::map<objectid64, objectid64> MapType;typedef std::map<objectid64, objectid64>::iterator MapTypeIterator;MapType m_object_list;MapTypeIterator m_object_it;};}}#endif

ObjectMap.cpp

#include "ObjectMap.h"namespace common{namespace tool{ObjectMap::ObjectMap(){write_lock lock(m_object_list_lock);m_object_list.clear();m_object_it = m_object_list.begin();}ObjectMap::~ObjectMap(){write_lock lock(m_object_list_lock);m_object_list.clear();m_object_it = m_object_list.begin();}void ObjectMap::AddObject(objectid64 key, objectid64 value){write_lock lock(m_object_list_lock);m_object_list[key] = value;}objectid64 ObjectMap::RandObject(){read_lock lock(m_object_list_lock);MapTypeIterator it = m_object_list.begin();if (it != m_object_list.end()){return it->second;}else{return NULL_ID;}}objectid64 ObjectMap::FindObject(objectid64 key){read_lock lock(m_object_list_lock);MapTypeIterator it = m_object_list.find(key);if (it != m_object_list.end()){return it->second;}else{return NULL_ID;}}bool ObjectMap::IsExistsObject(objectid64 key){read_lock lock(m_object_list_lock);MapTypeIterator it = m_object_list.find(key);if (it != m_object_list.end()){return true;}else{return false;}}void ObjectMap::FreeObject(objectid64 key){write_lock lock(m_object_list_lock);MapTypeIterator it = m_object_list.find(key);if (it != m_object_list.end()){// 删除结点if (m_object_it == it){m_object_list.erase(m_object_it++);}else{m_object_list.erase(it);}}}unsigned int ObjectMap::GetSize(){read_lock lock(m_object_list_lock);return m_object_list.size();}objectid64 ObjectMap::BeginObject(){write_lock lock(m_object_list_lock);m_object_it = m_object_list.begin();if (m_object_it != m_object_list.end()){return (m_object_it++)->second;}else{return NULL_ID;}}objectid64 ObjectMap::NextObject(){write_lock lock(m_object_list_lock);if (m_object_it != m_object_list.end()){return (m_object_it++)->second;}else{return NULL_ID;}}}}

其中ToolDefine.h增加了定义读写锁

//读写锁typedef boost::shared_mutex rw_mutex;typedef boost::shared_lock<rw_mutex> read_lock;typedef boost::unique_lock<rw_mutex> write_lock;