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/**
* Copyright (C) 2019-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* 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 Server Side 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 "mongo/db/operation_context.h"
#include "mongo/db/record_id.h"
#include "mongo/stdx/condition_variable.h"
#include "mongo/util/concurrency/mutex.h"
namespace mongo {
namespace ephemeral_for_test {
class RecordStore;
/**
* Manages oplog visibility by keeping track of uncommitted RecordIds and hiding Records from
* cursors while a given Record's RecordId is greater than the uncommitted RecordIds.
*/
class VisibilityManager {
public:
/**
* Removes the RecordId from the uncommitted records and notifies other threads that a chunk of
* the oplog became visible.
*/
void dealtWithRecord(RecordId rid);
/**
* Reserves a RecordId to be tracked before it is added. Used to ensure we don't skip over oplog
* holes when inserting out-of-order
*/
void reserveRecord(RecoveryUnit* recoveryUnit, RecordId rid);
/**
* Adds a RecordId to be tracked while its Record is uncommitted. Upon commit or rollback of
* the record, the appropriate actions are taken to change the visibility of the oplog.
*/
void addUncommittedRecord(OperationContext* opCtx, RecordStore* rs, RecordId rid);
/**
* Returns the highest seen RecordId such that it and all smaller RecordIds are committed or
* rolled back.
*/
RecordId getAllCommittedRecord();
/**
* Returns true if the given RecordId is the earliest uncommitted Record being tracked by the
* visibility manager, otherwise it returns false.
*/
bool isFirstHidden(RecordId rid);
/**
* Uses a condition variable to have all threads wait until all earlier oplog writes are visible
* based on the RecordId they're waiting for to become visible.
*/
void waitForAllEarlierOplogWritesToBeVisible(OperationContext* opCtx);
private:
mutable Mutex _stateLock =
MONGO_MAKE_LATCH("VisibilityManager::_stateLock"); // Protects the values below.
RecordId _highestSeen = RecordId();
// Used to wait for all earlier oplog writes to be visible.
mutable stdx::condition_variable _opsBecameVisibleCV;
std::set<RecordId> _uncommittedRecords; // RecordIds that have yet to be committed/rolled back.
};
} // namespace ephemeral_for_test
} // namespace mongo
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