125 lines
5.2 KiB
C++
125 lines
5.2 KiB
C++
/*
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* LMDB Abstraction Layer.
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* Copyright (C) 2023 Yury Gubich <blue@macaw.me>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef LMDBAL_CACHE_H
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#define LMDBAL_CACHE_H
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#include <map>
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#include <set>
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#include <tuple>
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#include "storage.h"
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namespace LMDBAL {
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template <class K, class V>
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class Cache : public Storage<K, V> {
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friend class Base;
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enum class Mode { /**<it's a cache state when we:*/
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nothing, /**< - know nothing about records in database on disk*/
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size, /**< - know just an amount of records*/
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full /**< - shure that our cache is equal to the database on disk*/
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};
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enum class Operation { /**<Operation type, used in pcrocessing cache modification after writable transaction is commited*/
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add,
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remove,
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change,
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force,
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drop,
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replace,
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addMany
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};
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typedef std::pair<Operation, void*> Entry;
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typedef std::list<Entry> Queue;
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typedef std::map<TransactionID, Queue> TransactionCache;
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protected:
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Cache(const std::string& name, Base* parent);
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~Cache() override;
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virtual void transactionStarted(TransactionID txn, bool readOnly) const override;
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virtual void transactionCommited(TransactionID txn) override;
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virtual void transactionAborted(TransactionID txn) const override;
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private:
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void handleMode() const;
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void handleTransactionEntry(const Entry& entry);
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void destroyTransactionEntry(const Entry& entry) const;
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void handleAddRecord(const K& key, const V& value);
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void handleRemoveRecord(const K& key);
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void handleChangeRecord(const K& key, const V& value);
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void handleForceRecord(const K& key, const V& value, bool added);
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void handleReplaceAll(std::map<K, V>* data);
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void handleAddRecords(const std::map<K, V>& data, bool overwrite, SizeType newSize);
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void handleDrop();
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public:
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using Storage<K, V>::drop;
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virtual int drop(TransactionID transaction) override;
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virtual void addRecord(const K& key, const V& value) override;
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virtual void addRecord(const K& key, const V& value, TransactionID txn) override;
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virtual bool forceRecord(const K& key, const V& value) override;
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virtual bool forceRecord(const K& key, const V& value, TransactionID txn) override;
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virtual void changeRecord(const K& key, const V& value) override;
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virtual void changeRecord(const K& key, const V& value, TransactionID txn) override;
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virtual void removeRecord(const K& key) override;
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virtual void removeRecord(const K& key, TransactionID txn) override;
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virtual bool checkRecord(const K& key) const override;
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virtual bool checkRecord(const K& key, TransactionID txn) const override;
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virtual void getRecord(const K& key, V& out) const override;
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virtual void getRecord(const K& key, V& out, TransactionID txn) const override;
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virtual V getRecord(const K& key) const override;
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virtual V getRecord(const K& key, TransactionID txn) const override;
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virtual SizeType count() const override;
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virtual SizeType count(TransactionID txn) const override;
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virtual std::map<K, V> readAll() const override;
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virtual std::map<K, V> readAll(TransactionID txn) const override;
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virtual void readAll(std::map<K, V>& out) const override;
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virtual void readAll(std::map<K, V>& out, TransactionID txn) const override;
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virtual void replaceAll(const std::map<K, V>& data) override;
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virtual void replaceAll(const std::map<K, V>& data, TransactionID txn) override;
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virtual SizeType addRecords(const std::map<K, V>& data, bool overwrite = false) override;
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virtual SizeType addRecords(const std::map<K, V>& data, TransactionID txn, bool overwrite = false) override;
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protected:
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/**
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* \brief Cache mode
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*
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* Sometimes we have a complete information about the content of the database,
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* and we don't even need to refer to lmdb to fetch or check for data.
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* This member actually shows what is the current state, more about them you can read in Enum descriptions
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*
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* It's done with pointer to comply some of the const method limitations which would modify this state eventually
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*/
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Mode* mode;
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std::map<K, V>* cache; /**<\brief Cached data*/
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std::set<K>* abscent; /**<\brief Set of keys that are definitely not in the cache*/
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SizeType* sizeDifference; /**<\brief Difference of size between cached data and amount of records in the lmdb storage*/
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TransactionCache* transactionCache; /**<\brief All changes made under under uncommited transactions*/
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};
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}
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#include "cache.hpp"
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#endif // LMDBAL_CACHE_H
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