cursorcommon.h

/*
 * LMDB Abstraction Layer.
 * Copyright (C) 2023  Yury Gubich <blue@macaw.me>
 *
 * 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.
 *
 * 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 <http://www.gnu.org/licenses/>.
 */
 
#pragma once
 
#include <stdint.h>
#include <string>
#include <string_view>
 
#include <lmdb.h>
 
namespace LMDBAL {
 
class Transaction;
class StorageCommon;
 
class CursorCommon {
    friend class Transaction;
protected:
    enum State {            
        closed,             
        openedPublic,       
        openedPrivate       
    };
 
protected:
    CursorCommon();
    CursorCommon(StorageCommon* storage);
    CursorCommon(const CursorCommon& other) = delete;
    CursorCommon(CursorCommon&& other);
    virtual ~CursorCommon() noexcept;
 
    CursorCommon& operator = (const CursorCommon& other) = delete;
    CursorCommon& operator = (CursorCommon&& other);
 
public:
    void open();
    void open(const Transaction& transaction);
    void renew();
    void renew(const Transaction& transaction);
    bool opened() const;
    bool empty() const;
    void close();
 
protected:
    void terminated();
    void dropped();
    void reset();
 
private:
    void attachToTransaction();
    void disconnectFromTransaction();
 
protected:
    uint32_t id;
    State state;
    MDB_cursor* handle;
    StorageCommon* storage;
 
private:
    inline static constexpr std::string_view openCursorMethodName = "Cursor::open";      
    inline static constexpr std::string_view closeCursorMethodName = "Cursor::close";    
    inline static constexpr std::string_view renewCursorMethodName = "Cursor::renew";    
 
protected:
    inline static constexpr std::string_view firstMethodName = "first";                  
    inline static constexpr std::string_view lastMethodName = "last";                    
    inline static constexpr std::string_view nextMethodName = "next";                    
    inline static constexpr std::string_view prevMethodName = "prev";                    
    inline static constexpr std::string_view currentMethodName = "current";              
    inline static constexpr std::string_view setMethodName = "set";                      
 
    inline static constexpr std::string_view firstOperationName = "Cursor::first";       
    inline static constexpr std::string_view lastOperationName = "Cursor::last";         
    inline static constexpr std::string_view nextOperationName = "Cursor::next";         
    inline static constexpr std::string_view prevOperationName = "Cursor::prev";         
    inline static constexpr std::string_view currentOperationName = "Cursor::current";   
};
 
}