95 lines
3.9 KiB
C++
95 lines
3.9 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_CURSOR_H
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#define LMDBAL_CURSOR_H
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#include <string>
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#include "lmdb.h"
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#include "base.h"
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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 Cursor {
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friend class Storage<K, V>;
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private:
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enum State { /**<Cursor state:*/
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closed, /**< - closed*/
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openedPublic, /**< - opened with public transaction, all storages will be notified about it after it's done*/
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openedPrivate /**< - opened with private transaction, only current storage will be notified when cursor is closed*/
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};
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Cursor(Storage<K, V>* parent);
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~Cursor();
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public:
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void open() const;
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void open(TransactionID txn) const;
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void renew() const;
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void renew(TransactionID txn) const;
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void close() const;
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bool opened() const;
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std::pair<K, V> first() const;
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std::pair<K, V> last() const;
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std::pair<K, V> next() const;
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std::pair<K, V> prev() const;
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std::pair<K, V> current() const;
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void first(K& key, V& value) const;
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void last(K& key, V& value) const;
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void next(K& key, V& value) const;
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void prev(K& key, V& value) const;
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void current(K& key, V& value) const;
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private:
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void terminated() const;
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void operateCursorRead(K& key, V& value, MDB_cursor_op operation, const std::string& methodName, const std::string& operationName) const;
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private:
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Storage<K, V>* storage;
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mutable MDB_cursor* cursor;
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mutable State state;
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inline static const std::string openCursorMethodName = "Cursor::open"; /**<\brief member function name, just for exceptions*/
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inline static const std::string closeCursorMethodName = "Cursor::close"; /**<\brief member function name, just for exceptions*/
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inline static const std::string renewCursorMethodName = "Cursor::renew"; /**<\brief member function name, just for exceptions*/
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inline static const std::string firstMethodName = "first"; /**<\brief member function name, just for exceptions*/
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inline static const std::string lastMethodName = "last"; /**<\brief member function name, just for exceptions*/
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inline static const std::string nextMethodName = "next"; /**<\brief member function name, just for exceptions*/
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inline static const std::string prevMethodName = "prev"; /**<\brief member function name, just for exceptions*/
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inline static const std::string currentMethodName = "current"; /**<\brief member function name, just for exceptions*/
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inline static const std::string firstOperationName = "Cursor::first"; /**<\brief member function name, just for exceptions*/
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inline static const std::string lastOperationName = "Cursor::last"; /**<\brief member function name, just for exceptions*/
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inline static const std::string nextOperationName = "Cursor::next"; /**<\brief member function name, just for exceptions*/
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inline static const std::string prevOperationName = "Cursor::prev"; /**<\brief member function name, just for exceptions*/
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inline static const std::string currentOperationName = "Cursor::current"; /**<\brief member function name, just for exceptions*/
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};
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};
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#include "cursor.hpp"
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#endif //LMDBAL_CURSOR_H
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