113 lines
2.8 KiB
C++
113 lines
2.8 KiB
C++
//
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// Created by Shell on 2026/7/13.
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//
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#ifndef SEADISK_CACHE_HPP
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#define SEADISK_CACHE_HPP
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#include <chrono>
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#include <shared_mutex>
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#include <unordered_map>
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namespace seafile::cache {
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template<typename K, typename V>
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class Cache final{
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public:
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using Clock = std::chrono::steady_clock;
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using Duration = Clock::duration;
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/// 设置缓存
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/// @param key 键
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/// @param value 值
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/// @param ttl 超时时间
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void put(const K &key, V value, const Duration ttl) {
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std::unique_lock lock(mutex_);
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cache_[key] = Entry{
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std::move(value),
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Clock::now() + ttl
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};
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}
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/// 获取缓存值
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/// @param key 键
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/// @return 缓存值
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std::optional<V> get(const K &key) {
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// 第一阶段：读锁
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{
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std::shared_lock lock(mutex_);
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auto it = cache_.find(key);
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if (it == cache_.end())
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return std::nullopt;
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if (Clock::now() < it->second.expire_time)
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return it->second.value;
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}
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// 第二阶段：删除过期数据
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{
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std::unique_lock lock(mutex_);
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auto it = cache_.find(key);
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if (it != cache_.end() &&
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Clock::now() >= it->second.expire_time)
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{
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cache_.erase(it);
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}
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}
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return std::nullopt;
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}
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/// 移除缓存
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/// @param key 键
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void remove(const K &key) {
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std::unique_lock lock(mutex_);
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cache_.erase(key);
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}
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///清空缓存
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void clear() {
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std::unique_lock lock(mutex_);
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cache_.clear();
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}
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///清理过时的缓存
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void cleanup() {
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auto now = Clock::now();
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std::unique_lock lock(mutex_);
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for (auto it = cache_.begin(); it != cache_.end();)
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{
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if (it->second.expireTime <= now)
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{
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it = cache_.erase(it);
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}
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else
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{
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++it;
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}
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}
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}
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///缓存大小
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size_t size() const {
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std::unique_lock lock(mutex_);
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return cache_.size();
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}
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private:
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struct Entry final {
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V value;
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Clock::time_point expire_time;
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};
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mutable std::shared_mutex mutex_;
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std::unordered_map<K, Entry> cache_;
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};
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}
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#endif //SEADISK_CACHE_HPP
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