当C++遇到IOS应用开发---LRUCache缓存(5)

            return &(iter->second); 
        } 
        else{ 
            return NULL; 
        } 
    } 
    
    
    unsigned get_lru_list_size(){ return (unsigned)_lru_list->size(); } 
    unsigned get_hash_table_size() { return (unsigned)_hash_table->size(); } 
    virtual_time get_now() { return _now; } 
    
private: 
    virtual_time get_virtual_time() 
    { 
        return ++_now; 
    } 
    
    shared_ptr<lru_map<virtual_time, HashKey> >    _lru_list; 
    shared_ptr<lru_map<HashKey, HashValue> > _hash_table; 
    virtual_time _now; 
}; 
    
#endif 

 

      接下来看一下如果结合单例和rwlock来设计最终的缓存功能，如下：

[cpp] 
using namespace lru_cache; 
class DZCache: public Singlton<DZCache> 
{ 
    friend  class Singlton<DZCache>; 
private: 
    shared_ptr<CLRUCache> clu_cache; 
    rwlock *lock; 
    DZCache(){ 
        lock =(rwlock*) malloc(sizeof(rwlock)); 
        rwlock_init(lock); 
        clu_cache = shared_ptr<CLRUCache>(new CLRUCache()); 
        cout << "construct JobList" << endl; 
    } 
    
    DZCache * Instance() { 
        return s_instance.get(); 
    } 
 
public: 
    
    ~DZCache(){ 
        free(lock); 
    } 
    
    static DZCache& getInstance(){ 
        return *instance(); 
    } 
 
    void set(NSString* key, id value){ 
        //加锁 
        rwlock_wlock(lock);