http_StaticFileMemoryCache.hpp

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#pragma once

namespace http
{

class StaticFileMemoryCache
{
public:
    struct CacheItem
    {
        time_t timeStamp;
        winux::String mime;
        winux::Buffer content;
    };

    // map< name, cache_item >
    typedef std::map< winux::String, CacheItem > CacheItemsMap;

    // 构造函数
    StaticFileMemoryCache( time_t lifeTime = 0 ) : _cacheLifeTime(lifeTime), _mtxCache(true)
    {
    }

    bool hasCache( winux::String const & cacheName ) const
    {
        if ( this->_cacheLifeTime < 1 ) //如果未开启缓存功能，直接返回false
        {
            return false;
        }
        if ( true )
        {
            winux::ScopeGuard guard( const_cast<winux::RecursiveMutex &>(_mtxCache) );
            if ( winux::isset( this->_cacheItems, cacheName ) ) // 存在缓存
            {
                time_t cacheFileMTime = this->_cacheItems.at(cacheName).timeStamp; //取得最后修改时间
                if ( cacheFileMTime + this->_cacheLifeTime >= winux::GetUtcTime() ) // 尚未过期
                {
                    return true;
                }
            }
        }
        return false;
    }

    CacheItem const & get( winux::String const & cacheName ) const
    {
        winux::ScopeGuard guard( const_cast<winux::RecursiveMutex &>(_mtxCache) );
        return this->_cacheItems.at(cacheName);
    }

    CacheItem & writeCache( winux::String const & cacheName, winux::String mime, winux::Buffer content )
    {
        CacheItem * item = nullptr;
        if ( true )
        {
            winux::ScopeGuard guard( const_cast<winux::RecursiveMutex &>(_mtxCache) );
            item = &this->_cacheItems[cacheName];
            item->timeStamp = winux::GetUtcTime();
            item->mime = std::move(mime);
            item->content = std::move(content);
        }
        return *item;
    }

    void setLifeTime( time_t lifeTime = 0 )
    {
        this->_cacheLifeTime = lifeTime;
    }

    time_t getLifeTime() const
    {
        return this->_cacheLifeTime;
    }
private:
    time_t _cacheLifeTime; // 缓存生命期 0表示不缓存
    CacheItemsMap _cacheItems;
    winux::RecursiveMutex _mtxCache;
};


} // namespace http