# HG changeset patch # User Sebastien Jodogne # Date 1480326048 -3600 # Node ID ea6309f70f1f26513f11f1c2a2329c22213303eb # Parent 326959045d12b7c2982c090bec9afcc231c3eb69 new file: Orthanc/Core/Cache/LeastRecentlyUsedIndex.h diff -r 326959045d12 -r ea6309f70f1f Resources/Orthanc/Core/Cache/LeastRecentlyUsedIndex.h --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/Resources/Orthanc/Core/Cache/LeastRecentlyUsedIndex.h Mon Nov 28 10:40:48 2016 +0100 @@ -0,0 +1,346 @@ +/** + * Orthanc - A Lightweight, RESTful DICOM Store + * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics + * Department, University Hospital of Liege, Belgium + * + * This program is free software: you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation, either version 3 of the + * License, or (at your option) any later version. + * + * In addition, as a special exception, the copyright holders of this + * program give permission to link the code of its release with the + * OpenSSL project's "OpenSSL" library (or with modified versions of it + * that use the same license as the "OpenSSL" library), and distribute + * the linked executables. You must obey the GNU General Public License + * in all respects for all of the code used other than "OpenSSL". If you + * modify file(s) with this exception, you may extend this exception to + * your version of the file(s), but you are not obligated to do so. If + * you do not wish to do so, delete this exception statement from your + * version. If you delete this exception statement from all source files + * in the program, then also delete it here. + * + * 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 + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + **/ + + +#pragma once + +#include +#include +#include +#include + +#include "../OrthancException.h" +#include "../Toolbox.h" + +namespace Orthanc +{ + /** + * This class implements the index of a cache with least recently + * used (LRU) recycling policy. All the items of the cache index + * can be associated with a payload. + * Reference: http://stackoverflow.com/a/2504317 + **/ + template + class LeastRecentlyUsedIndex : public boost::noncopyable + { + private: + typedef std::list< std::pair > Queue; + typedef std::map Index; + + Index index_; + Queue queue_; + + /** + * Internal method for debug builds to check whether the internal + * data structures are not corrupted. + **/ + void CheckInvariants() const; + + public: + /** + * Add a new element to the cache index, and make it the most + * recent element. + * \param id The ID of the element. + * \param payload The payload of the element. + **/ + void Add(T id, Payload payload = Payload()); + + void AddOrMakeMostRecent(T id, Payload payload = Payload()); + + /** + * When accessing an element of the cache, this method tags the + * element as the most recently used. + * \param id The most recently accessed item. + **/ + void MakeMostRecent(T id); + + void MakeMostRecent(T id, Payload updatedPayload); + + /** + * Remove an element from the cache index. + * \param id The item to remove. + **/ + Payload Invalidate(T id); + + /** + * Get the oldest element in the cache and remove it. + * \return The oldest item. + **/ + T RemoveOldest(); + + /** + * Get the oldest element in the cache, remove it and return the + * associated payload. + * \param payload Where to store the associated payload. + * \return The oldest item. + **/ + T RemoveOldest(Payload& payload); + + /** + * Check whether an element is contained in the cache. + * \param id The item. + * \return \c true iff the item is indexed by the cache. + **/ + bool Contains(T id) const + { + return index_.find(id) != index_.end(); + } + + bool Contains(T id, Payload& payload) const + { + typename Index::const_iterator it = index_.find(id); + if (it == index_.end()) + { + return false; + } + else + { + payload = it->second->second; + return true; + } + } + + /** + * Return the number of elements in the cache. + * \return The number of elements. + **/ + size_t GetSize() const + { + assert(index_.size() == queue_.size()); + return queue_.size(); + } + + /** + * Check whether the cache index is empty. + * \return \c true iff the cache is empty. + **/ + bool IsEmpty() const + { + return index_.empty(); + } + + const T& GetOldest() const; + + const Payload& GetOldestPayload() const; + }; + + + + + /****************************************************************** + ** Implementation of the template + ******************************************************************/ + + template + void LeastRecentlyUsedIndex::CheckInvariants() const + { +#ifndef NDEBUG + assert(index_.size() == queue_.size()); + + for (typename Index::const_iterator + it = index_.begin(); it != index_.end(); it++) + { + assert(it->second != queue_.end()); + assert(it->second->first == it->first); + } +#endif + } + + + template + void LeastRecentlyUsedIndex::Add(T id, Payload payload) + { + if (Contains(id)) + { + throw OrthancException(ErrorCode_BadSequenceOfCalls); + } + + queue_.push_front(std::make_pair(id, payload)); + index_[id] = queue_.begin(); + + CheckInvariants(); + } + + + template + void LeastRecentlyUsedIndex::MakeMostRecent(T id) + { + if (!Contains(id)) + { + throw OrthancException(ErrorCode_InexistentItem); + } + + typename Index::iterator it = index_.find(id); + assert(it != index_.end()); + + std::pair item = *(it->second); + + queue_.erase(it->second); + queue_.push_front(item); + index_[id] = queue_.begin(); + + CheckInvariants(); + } + + + template + void LeastRecentlyUsedIndex::AddOrMakeMostRecent(T id, Payload payload) + { + typename Index::iterator it = index_.find(id); + + if (it != index_.end()) + { + // Already existing. Make it most recent. + std::pair item = *(it->second); + item.second = payload; + queue_.erase(it->second); + queue_.push_front(item); + } + else + { + // New item + queue_.push_front(std::make_pair(id, payload)); + } + + index_[id] = queue_.begin(); + + CheckInvariants(); + } + + + template + void LeastRecentlyUsedIndex::MakeMostRecent(T id, Payload updatedPayload) + { + if (!Contains(id)) + { + throw OrthancException(ErrorCode_InexistentItem); + } + + typename Index::iterator it = index_.find(id); + assert(it != index_.end()); + + std::pair item = *(it->second); + item.second = updatedPayload; + + queue_.erase(it->second); + queue_.push_front(item); + index_[id] = queue_.begin(); + + CheckInvariants(); + } + + + template + Payload LeastRecentlyUsedIndex::Invalidate(T id) + { + if (!Contains(id)) + { + throw OrthancException(ErrorCode_InexistentItem); + } + + typename Index::iterator it = index_.find(id); + assert(it != index_.end()); + + Payload payload = it->second->second; + queue_.erase(it->second); + index_.erase(it); + + CheckInvariants(); + return payload; + } + + + template + T LeastRecentlyUsedIndex::RemoveOldest(Payload& payload) + { + if (IsEmpty()) + { + throw OrthancException(ErrorCode_BadSequenceOfCalls); + } + + std::pair item = queue_.back(); + T oldest = item.first; + payload = item.second; + + queue_.pop_back(); + assert(index_.find(oldest) != index_.end()); + index_.erase(oldest); + + CheckInvariants(); + + return oldest; + } + + + template + T LeastRecentlyUsedIndex::RemoveOldest() + { + if (IsEmpty()) + { + throw OrthancException(ErrorCode_BadSequenceOfCalls); + } + + std::pair item = queue_.back(); + T oldest = item.first; + + queue_.pop_back(); + assert(index_.find(oldest) != index_.end()); + index_.erase(oldest); + + CheckInvariants(); + + return oldest; + } + + + template + const T& LeastRecentlyUsedIndex::GetOldest() const + { + if (IsEmpty()) + { + throw OrthancException(ErrorCode_BadSequenceOfCalls); + } + + return queue_.back().first; + } + + + template + const Payload& LeastRecentlyUsedIndex::GetOldestPayload() const + { + if (IsEmpty()) + { + throw OrthancException(ErrorCode_BadSequenceOfCalls); + } + + return queue_.back().second; + } +} diff -r 326959045d12 -r ea6309f70f1f Resources/SyncOrthancFolder.py --- a/Resources/SyncOrthancFolder.py Mon Nov 28 09:14:31 2016 +0100 +++ b/Resources/SyncOrthancFolder.py Mon Nov 28 10:40:48 2016 +0100 @@ -15,6 +15,7 @@ REPOSITORY = 'http://bitbucket.org/sjodogne/orthanc/raw' FILES = [ + 'Core/Cache/LeastRecentlyUsedIndex.h', 'Core/ChunkedBuffer.cpp', 'Core/ChunkedBuffer.h', 'Core/DicomFormat/DicomArray.cpp',