OverlayDB.h

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/*
    This file is part of cpp-ethereum.
 
    cpp-ethereum 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.
 
    cpp-ethereum 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 cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
 
#include <memory>
#include <libdevcore/db.h>
#include <libdevcore/Common.h>
#include <libdevcore/Log.h>
#include <libdevcore/StateCacheDB.h>
 
namespace dev
{
 
class OverlayDB: public StateCacheDB
{
public:
    explicit OverlayDB(std::unique_ptr<db::DatabaseFace> _db = nullptr)
      : m_db(_db.release(), [](db::DatabaseFace* db) {
            clog(VerbosityDebug, "overlaydb") << "Closing state DB";
            delete db;
        })
    {}
 
    ~OverlayDB();
 
    // Copyable
    OverlayDB(OverlayDB const&) = default;
    OverlayDB& operator=(OverlayDB const&) = default;
    // Movable
    OverlayDB(OverlayDB&&) = default;
    OverlayDB& operator=(OverlayDB&&) = default;
 
    void commit();
    void rollback();
 
    std::string lookup(h256 const& _h) const;
    bool exists(h256 const& _h) const;
    void kill(h256 const& _h);
 
    bytes lookupAux(h256 const& _h) const;
 
private:
    using StateCacheDB::clear;
 
    std::shared_ptr<db::DatabaseFace> m_db;
};
 
}