Viewing file:  lru_cache.h (2.29 KB) -rw-r--r--
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#pragma once
#include <unordered_map>
#include <list>
#include <utility>
#include <memory>
#include <time.h>
namespace swoole
{
/**
* This cache isn't thread safe
*/
class LRUCache
{
private:
typedef std::pair<time_t, std::shared_ptr<void>> cache_node_t;
typedef std::list<std::pair<std::string, cache_node_t>> cache_list_t;
std::unordered_map<std::string, cache_list_t::iterator> cache_map;
cache_list_t cache_list;
size_t cache_capacity;
public:
explicit LRUCache(size_t capacity)
{
cache_capacity = capacity;
}
inline std::shared_ptr<void> get(const std::string &key)
{
auto iter = cache_map.find(key);
if (iter == cache_map.end())
{
return nullptr;
}
if (iter->second->second.first < time(nullptr) && iter->second->second.first > 0)
{
return nullptr;
}
cache_list.splice(cache_list.begin(), cache_list, iter->second);
return iter->second->second.second; // iter -> list::iter -> cache_node_t -> value
}
inline void set(const std::string &key, const std::shared_ptr<void> &val, time_t expire = 0)
{
time_t expire_time;
if (expire <= 0)
{
expire_time = 0;
}
else
{
expire_time = time(nullptr) + expire;
}
auto iter = cache_map.find(key);
if (iter != cache_map.end())
{
iter->second->second.first = expire_time;
iter->second->second.second = val;
cache_list.splice(cache_list.begin(), cache_list, iter->second);
return;
}
size_t size = cache_list.size();
if (size == cache_capacity && size > 0)
{
auto del = cache_list.back();
cache_map.erase(del.first);
cache_list.pop_back();
}
cache_list.emplace_front(key, cache_node_t{expire_time, val});
cache_map[key] = cache_list.begin();
}
inline void del(const std::string &key)
{
auto iter = cache_map.find(key);
if (iter == cache_map.end())
{
return;
}
cache_list.erase(iter->second);
cache_map.erase(iter);
}
inline void clear()
{
cache_list.clear();
cache_map.clear();
}
};
}
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