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/**
* Copyright (C) 2021-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 <shared_mutex>
#include "mongo/db/operation_id.h"
#include "mongo/db/service_context.h"
#include "mongo/db/storage/storage_change_lock.h"
#include "mongo/db/storage/storage_engine.h"
#include "mongo/stdx/condition_variable.h"
#include "mongo/stdx/unordered_set.h"
namespace mongo {
class StorageEngineChangeContext {
public:
static StorageEngineChangeContext* get(ServiceContext* service);
/**
* Start to change the storage engine for the associated ServiceContext. This will kill all
* OperationContexts that have a non-noop Recovery Unit with an InterruptedDueToStorageChange
* code, free the existing storage engine, and block any new operation contexts from being
* created while the returned StorageChangeToken is in scope.
*/
StorageChangeLock::Token killOpsForStorageEngineChange(ServiceContext* service);
/**
* Finish changing the storage engine for the associated ServiceContext. This will change the
* storage engine and allow operation contexts to again be created.
*/
void changeStorageEngine(ServiceContext* service,
StorageChangeLock::Token token,
std::unique_ptr<StorageEngine> engine);
/**
* Called by the decorator's destructor to tell us that an opCtx with the old storage engine has
* been destroyed.
*/
void notifyOpCtxDestroyed() noexcept;
private:
Mutex _mutex = MONGO_MAKE_LATCH("StorageEngineChangeContext::_mutex");
// Keeps track of opCtxs associated with a storage engine that is being replaced.
// Protected by _mutex
int _numOpCtxtsToWaitFor = 0;
stdx::condition_variable _allOldStorageOperationContextsReleased;
};
} // namespace mongo
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