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/**
* Copyright (C) 2022-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/concurrency/d_concurrency.h"
#include "mongo/db/service_context.h"
#include "mongo/platform/mutex.h"
#include "mongo/util/uuid.h"
#include <set>
namespace mongo {
/**
* Registry to allow only one type of active serverless operation at a time. It allows multiple
* simultaneous operations of the same type.
*/
class ServerlessOperationLockRegistry {
ServerlessOperationLockRegistry(const ServerlessOperationLockRegistry&) = delete;
ServerlessOperationLockRegistry& operator=(const ServerlessOperationLockRegistry&) = delete;
public:
ServerlessOperationLockRegistry() = default;
static const ServiceContext::Decoration<ServerlessOperationLockRegistry> get;
enum LockType { kShardSplit, kTenantDonor, kTenantRecipient, kMergeRecipient };
/**
* Acquire the serverless lock for LockType and adds operationId to the set of
* instances tracked. Throws ConflictingServerlessOperation error if there is already an
* activeServerlessOperation in progress with a different namespace than operationNamespace.
*/
void acquireLock(LockType lockType, const UUID& operationId);
/**
* If _activeOpSeverlessOperation matches LockType, removes the given operationId from
* the set of active instances and releases the lock if the set becomes empty. Invariant if
* lockType or operationId does not own the lock.
*/
void releaseLock(LockType lockType, const UUID& operationId);
/**
* Called when a state document collection is dropped. If the collection's lockType currently
* holds the lock, it releases the lock. If it does not own the lock, the function does nothing.
*/
void onDropStateCollection(LockType lockType);
void clear();
/**
* Scan serverless state documents and acquire the serverless mutual exclusion lock if needed.
*/
static void recoverLocks(OperationContext* opCtx);
/**
* Appends the exclusion status to the BSONObjBuilder.
*/
void appendInfoForServerStatus(BSONObjBuilder* builder) const;
boost::optional<ServerlessOperationLockRegistry::LockType> getActiveOperationType_forTest();
private:
mutable Mutex _mutex = MONGO_MAKE_LATCH("ServerlessMutualExclusionRegistry::_mutex");
boost::optional<LockType> _activeLockType;
std::set<UUID> _activeOperations;
};
} // namespace mongo
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