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/**
* Copyright (C) 2014 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 "mongo/base/disallow_copying.h"
#include "mongo/base/status.h"
#include "mongo/db/query/plan_executor.h"
namespace mongo {
class CanonicalQuery;
class Database;
class DeleteRequest;
class OperationContext;
/**
* This class takes a pointer to a DeleteRequest, and converts that request into a parsed form
* via the parseRequest() method. A ParsedDelete can then be used to retrieve a PlanExecutor
* capable of executing the delete.
*
* It is invalid to request that the DeleteStage return the deleted document during a
* multi-remove. It is also invalid to request that a ProjectionStage be applied to the
* DeleteStage if the DeleteStage would not return the deleted document.
*
* A delete request is parsed to a CanonicalQuery, so this class is a thin, delete-specific
* wrapper around canonicalization.
*
* No locks need to be held during parsing.
*/
class ParsedDelete {
MONGO_DISALLOW_COPYING(ParsedDelete);
public:
/**
* Constructs a parsed delete.
*
* The object pointed to by "request" must stay in scope for the life of the constructed
* ParsedDelete.
*/
ParsedDelete(OperationContext* txn, const DeleteRequest* request);
/**
* Parses the delete request to a canonical query. On success, the parsed delete can be
* used to create a PlanExecutor capable of executing this delete.
*/
Status parseRequest();
/**
* As an optimization, we do not create a canonical query if the predicate is a simple
* _id equality. This method can be used to force full parsing to a canonical query,
* as a fallback if the idhack path is not available (e.g. no _id index).
*/
Status parseQueryToCQ();
/**
* Get the raw request.
*/
const DeleteRequest* getRequest() const;
/**
* Is this delete allowed to yield?
*/
bool canYield() const;
/**
* Is this update supposed to be isolated?
*/
bool isIsolated() const;
/**
* As an optimization, we don't create a canonical query for updates with simple _id
* queries. Use this method to determine whether or not we actually parsed the query.
*/
bool hasParsedQuery() const;
/**
* Releases ownership of the canonical query to the caller.
*/
CanonicalQuery* releaseParsedQuery();
private:
// Transactional context. Not owned by us.
OperationContext* _txn;
// Unowned pointer to the request object that this executor will process.
const DeleteRequest* const _request;
// Parsed query object, or NULL if the query proves to be an id hack query.
std::unique_ptr<CanonicalQuery> _canonicalQuery;
};
} // namespace mongo
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