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/**
* Copyright (C) 2018-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/base/disallow_copying.h"
#include "mongo/base/string_data.h"
#include "mongo/bson/oid.h"
#include "mongo/db/write_concern_options.h"
#include "mongo/util/time_support.h"
namespace mongo {
class LockpingsType;
class LocksType;
class OperationContext;
class Status;
template <typename T>
class StatusWith;
/**
* Interface for the distributed lock operations.
*/
class DistLockCatalog {
MONGO_DISALLOW_COPYING(DistLockCatalog);
public:
static const WriteConcernOptions kLocalWriteConcern;
static const WriteConcernOptions kMajorityWriteConcern;
/**
* Simple data structure for storing server local time and election id.
*/
struct ServerInfo {
public:
ServerInfo(Date_t time, OID electionId);
// The local time of the server at the time this was created.
Date_t serverTime;
// The election id of the replica set member at the time this was created.
OID electionId;
};
virtual ~DistLockCatalog() = default;
/**
* Returns the ping document of the specified processID.
* Common status errors include socket errors.
*/
virtual StatusWith<LockpingsType> getPing(OperationContext* opCtx, StringData processID) = 0;
/**
* Updates the ping document. Creates a new entry if it does not exists.
* Common status errors include socket errors.
*/
virtual Status ping(OperationContext* opCtx, StringData processID, Date_t ping) = 0;
/**
* Attempts to update the owner of a lock identified by lockID to lockSessionID.
* Will only be successful if lock is not held.
*
* The other parameters are for diagnostic purposes:
* - who: unique string for the caller trying to grab the lock.
* - processId: unique string for the process trying to grab the lock.
* - time: the time when this is attempted.
* - why: reason for taking the lock.
*
* Returns the result of the operation.
* Returns LockStateChangeFailed if the lock acquisition cannot be done because lock
* is already held elsewhere.
*
* Common status errors include socket and duplicate key errors.
*/
virtual StatusWith<LocksType> grabLock(
OperationContext* opCtx,
StringData lockID,
const OID& lockSessionID,
StringData who,
StringData processId,
Date_t time,
StringData why,
const WriteConcernOptions& writeConcern = kMajorityWriteConcern) = 0;
/**
* Attempts to forcefully transfer the ownership of a lock from currentHolderTS
* to lockSessionID.
*
* The other parameters are for diagnostic purposes:
* - who: unique string for the caller trying to grab the lock.
* - processId: unique string for the process trying to grab the lock.
* - time: the time when this is attempted.
* - why: reason for taking the lock.
*
* Returns the result of the operation.
* Returns LockStateChangeFailed if the lock acquisition fails.
*
* Common status errors include socket errors.
*/
virtual StatusWith<LocksType> overtakeLock(OperationContext* opCtx,
StringData lockID,
const OID& lockSessionID,
const OID& currentHolderTS,
StringData who,
StringData processId,
Date_t time,
StringData why) = 0;
/**
* Attempts to set the state of the lock document with lockSessionID to unlocked. Returns OK,
* if at the end of this call it is determined that the lock is definitely not owned by the
* specified session (i.e., it is not owned at all or if it is owned by a different session).
* Otherwise, it returns an error status. Common errors include socket errors.
*/
virtual Status unlock(OperationContext* opCtx, const OID& lockSessionID) = 0;
/**
* Same as unlock() above except that it unlocks the lock document that matches "lockSessionID"
* AND "name", rather than just "lockSessionID". This is necessary if multiple documents have
* been locked with the same lockSessionID.
*/
virtual Status unlock(OperationContext* opCtx, const OID& lockSessionID, StringData name) = 0;
/**
* Unlocks all distributed locks with the given owning process ID. Does not provide any
* indication as to how many locks were actually unlocked. So long as the update command runs
* successfully, returns OK, otherwise returns an error status.
*/
virtual Status unlockAll(OperationContext* opCtx, const std::string& processID) = 0;
/**
* Get some information from the config server primary.
* Common status errors include socket errors.
*/
virtual StatusWith<ServerInfo> getServerInfo(OperationContext* opCtx) = 0;
/**
* Returns the lock document.
* Returns LockNotFound if lock document doesn't exist.
* Common status errors include socket errors.
*/
virtual StatusWith<LocksType> getLockByTS(OperationContext* opCtx,
const OID& lockSessionID) = 0;
/**
* Returns the lock document.
* Common status errors include socket errors.
*/
virtual StatusWith<LocksType> getLockByName(OperationContext* opCtx, StringData name) = 0;
/**
* Attempts to delete the ping document corresponding to the given processId.
* Common status errors include socket errors.
*/
virtual Status stopPing(OperationContext* opCtx, StringData processId) = 0;
protected:
DistLockCatalog();
};
} // namespace mongo
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