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/**
* Copyright (C) 2016 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.hpp>
#include <string>
#include "mongo/base/disallow_copying.h"
#include "mongo/base/string_data.h"
namespace mongo {
class BSONObj;
class BSONObjBuilder;
template <typename T>
class StatusWith;
/**
* Encapsulates the logic for generating, parsing and comparing migration sessions. The migration
* session id is a unique identifier for a particular moveChunk command and is exchanged as part of
* all communication between the source and donor shards.
*/
class MigrationSessionId {
public:
/**
* Constructs a new migration session identifier with the following format:
* DonorId_RecipientId_UniqueIdentifier
*/
static MigrationSessionId generate(StringData donor, StringData recipient);
/**
* Extracts the session id from BSON. If the session id is missing from the BSON contents,
* returns a NoSuchKey error.
*/
static StatusWith<MigrationSessionId> extractFromBSON(const BSONObj& obj);
/**
* Same as extractFromBSON, but throws on error.
* Function signature is compatible for idl.
*/
static MigrationSessionId parseFromBSON(const BSONObj& obj);
/**
* Compares two session identifiers. Two idendifiers match only if they are the same.
*/
bool matches(const MigrationSessionId& other) const;
/**
* Appends the migration session id to the specified builder.
*/
void append(BSONObjBuilder* builder) const;
std::string toString() const;
private:
explicit MigrationSessionId(std::string sessionId);
std::string _sessionId;
};
} // namespace mongo
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