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/**
* Copyright (C) 2018 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include <boost/optional/optional.hpp>
#include <map>
#include <memory>
#include "mongo/base/disallow_copying.h"
#include "mongo/db/logical_session_id.h"
#include "mongo/stdx/mutex.h"
namespace mongo {
class TransactionCoordinator;
/**
* A container for TransactionCoordinator objects, indexed by logical session id and transaction
* number. It allows holding several coordinator objects per session. It also knows how to recreate
* itself from the config.txnCommitDecisions collection, which will be done on transition to
* primary (whether from startup or ordinary step up).
*/
class TransactionCoordinatorCatalog
: public std::enable_shared_from_this<TransactionCoordinatorCatalog> {
MONGO_DISALLOW_COPYING(TransactionCoordinatorCatalog);
public:
TransactionCoordinatorCatalog();
virtual ~TransactionCoordinatorCatalog();
/**
* Creates a coordinator, inserts it into the catalog, and returns the newly created
* coordinator.
*
* Note: Creating a duplicate coordinator for the given session id and transaction number
* is not allowed and will lead to an invariant failure. Users of the catalog must ensure this
* does not take place.
*/
std::shared_ptr<TransactionCoordinator> create(LogicalSessionId lsid, TxnNumber txnNumber);
/**
* Returns the coordinator with the given session id and transaction number, if it exists. If it
* does not exist, return boost::none.
*/
boost::optional<std::shared_ptr<TransactionCoordinator>> get(LogicalSessionId lsid,
TxnNumber txnNumber);
/**
* Returns the coordinator with the highest transaction number with the given session id, if it
* exists. If it does not exist, return boost::none.
*/
boost::optional<std::pair<TxnNumber, std::shared_ptr<TransactionCoordinator>>>
getLatestOnSession(LogicalSessionId lsid);
/**
* Removes the coordinator with the given session id and transaction number from the catalog, if
* one exists.
*
* Note: The coordinator must be in a state suitable for removal (i.e. committed or aborted).
*/
void remove(LogicalSessionId lsid, TxnNumber txnNumber);
private:
/**
* Protects the _coordinatorsBySession map.
*/
stdx::mutex _mutex;
/**
* Contains TransactionCoordinator objects by session id and transaction number. May contain
* more than one coordinator per session. All coordinators for a session that do not correspond
* to the latest transaction should either be in the process of committing or aborting.
*/
LogicalSessionIdMap<std::map<TxnNumber, std::shared_ptr<TransactionCoordinator>>>
_coordinatorsBySession;
};
} // namespace mongo
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