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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/platform/basic.h"
#include "mongo/db/exec/shard_filterer.h"
#include "mongo/db/exec/working_set.h"
#include "mongo/db/namespace_string.h"
namespace mongo {
class CanonicalQuery;
class Collection;
class CollectionPtr;
class OperationContext;
class BSONObj;
class Document;
namespace write_stage_common {
class PreWriteFilter {
public:
/**
* This class represents the different kind of actions we can take when handling a write
* operation:
* - kWrite: perform the current write operation.
* - kWriteAsFromMigrate: perform the current write operation but marking it with the
* fromMigrate flag.
* - kSkip: skip the current write operation.
*/
enum class Action { kWrite, kWriteAsFromMigrate, kSkip };
PreWriteFilter(OperationContext* opCtx, NamespaceString nss);
void saveState() {}
void restoreState();
/**
* Returns which PreWriteFilterAction we should take for the current write operation over doc.
*/
Action computeAction(const Document& doc);
private:
/**
* Returns true if the operation is not versioned or if the doc is owned by the shard.
*
* May thow a ShardKeyNotFound if the document has an invalid shard key.
*/
bool _documentBelongsToMe(const BSONObj& doc);
OperationContext* _opCtx;
NamespaceString _nss;
const bool _isEnabled;
const bool _isStandaloneOrPrimary;
std::unique_ptr<ShardFilterer> _shardFilterer;
};
/**
* Returns true if the document referred to by 'id' still exists and matches the query predicate
* given by 'cq'. Returns true if the document still exists and 'cq' is null. Returns false
* otherwise.
*
* May throw a WriteConflictException if there was a conflict while searching to see if the document
* still exists.
*/
bool ensureStillMatches(const CollectionPtr& collection,
OperationContext* opCtx,
WorkingSet* ws,
WorkingSetID id,
const CanonicalQuery* cq);
} // namespace write_stage_common
} // namespace mongo
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