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/*
* Copyright (C) 2018 Codership Oy <info@codership.com>
*
* This file is part of wsrep-lib.
*
* Wsrep-lib 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 2 of the License, or
* (at your option) any later version.
*
* Wsrep-lib 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 wsrep-lib. If not, see <https://www.gnu.org/licenses/>.
*/
#ifndef WSREP_DB_STORAGE_ENGINE_HPP
#define WSREP_DB_STORAGE_ENGINE_HPP
#include "db_params.hpp"
#include "wsrep/mutex.hpp"
#include "wsrep/view.hpp"
#include "wsrep/transaction.hpp"
#include <atomic>
#include <unordered_set>
#include <random>
namespace db
{
class client;
class storage_engine
{
public:
storage_engine(const params& params)
: mutex_()
, transactions_()
, alg_freq_(params.alg_freq)
, bf_aborts_()
, position_()
, view_()
, random_device_()
, random_engine_(random_device_())
{ }
class transaction
{
public:
transaction(storage_engine& se)
: se_(se)
, cc_()
{ }
~transaction()
{
rollback();
}
bool active() const { return cc_ != nullptr; }
void start(client* cc);
void apply(const wsrep::transaction&);
void commit(const wsrep::gtid&);
void rollback();
db::client* client() { return cc_; }
transaction(const transaction&) = delete;
transaction& operator=(const transaction&) = delete;
private:
db::storage_engine& se_;
db::client* cc_;
};
void bf_abort_some(const wsrep::transaction& tc);
long long bf_aborts() const { return bf_aborts_; }
void store_position(const wsrep::gtid& gtid);
wsrep::gtid get_position() const;
void store_view(const wsrep::view& view);
wsrep::view get_view() const;
private:
void validate_position(const wsrep::gtid& gtid) const;
wsrep::default_mutex mutex_;
std::unordered_set<db::client*> transactions_;
size_t alg_freq_;
std::atomic<long long> bf_aborts_;
wsrep::gtid position_;
wsrep::view view_;
std::random_device random_device_;
std::default_random_engine random_engine_;
};
}
#endif // WSREP_DB_STORAGE_ENGINE_HPP
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