Mercurial > hg > orthanc
view OrthancFramework/Sources/Cache/MemoryStringCache.h @ 5735:0ca3e7c86b5d
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author | Alain Mazy <am@orthanc.team> |
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date | Mon, 29 Jul 2024 14:41:38 +0200 |
parents | f7adfb22e20e |
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/** * Orthanc - A Lightweight, RESTful DICOM Store * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics * Department, University Hospital of Liege, Belgium * Copyright (C) 2017-2023 Osimis S.A., Belgium * Copyright (C) 2024-2024 Orthanc Team SRL, Belgium * Copyright (C) 2021-2024 Sebastien Jodogne, ICTEAM UCLouvain, Belgium * * This program is free software: you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public License * as published by the Free Software Foundation, either version 3 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this program. If not, see * <http://www.gnu.org/licenses/>. **/ #pragma once #include "../OrthancFramework.h" #include "ICacheable.h" #include "LeastRecentlyUsedIndex.h" #include <boost/thread/condition_variable.hpp> #include <boost/thread/mutex.hpp> namespace Orthanc { /** * Class that caches a dictionary * of strings, using the "fetch/add" paradigm of memcached. * * Starting from 1.12.2, if multiple clients are trying to access * an inexistent item at the same time, only one of them will load it * and the others will wait until the first one has loaded the data. * * The MemoryStringCache is only accessible through an Accessor. * * Note: this class is thread safe **/ class ORTHANC_PUBLIC MemoryStringCache : public boost::noncopyable { public: class ORTHANC_PUBLIC Accessor : public boost::noncopyable { protected: MemoryStringCache& cache_; private: bool shouldAdd_; // when this accessor is the one who should load and add the data std::string keyToAdd_; public: explicit Accessor(MemoryStringCache& cache); ~Accessor(); bool Fetch(std::string& value, const std::string& key); void Add(const std::string& key, const std::string& value); void Add(const std::string& key,const char* buffer, size_t size); }; private: class StringValue; mutable boost::mutex cacheMutex_; // note: we can not use recursive_mutex with condition_variable boost::condition_variable cacheCond_; std::set<std::string> itemsBeingLoaded_; size_t currentSize_; size_t maxSize_; LeastRecentlyUsedIndex<std::string, StringValue*> content_; void Recycle(size_t targetSize); public: MemoryStringCache(); ~MemoryStringCache(); size_t GetMaximumSize(); void SetMaximumSize(size_t size); void Invalidate(const std::string& key); size_t GetCurrentSize() const; size_t GetNumberOfItems() const; private: void Add(const std::string& key, const std::string& value); void Add(const std::string& key, const void* buffer, size_t size); bool Fetch(std::string& value, const std::string& key); void RemoveFromItemsBeingLoaded(const std::string& key); void RemoveFromItemsBeingLoadedInternal(const std::string& key); void AddToItemsBeingLoadedInternal(const std::string& key); }; }