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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/ops/update_driver.h"
namespace mongo {
class CanonicalQuery;
class OperationContext;
class UpdateRequest;
/**
* This class takes a pointer to an UpdateRequest, and converts that request into a parsed form
* via the parseRequest() method. A ParsedUpdate can then be used to retrieve a PlanExecutor
* capable of executing the update.
*
* It is invalid to request that the UpdateStage return the prior or newly-updated version of a
* document during a multi-update. It is also invalid to request that a ProjectionStage be
* applied to the UpdateStage if the UpdateStage would not return any document.
*
* No locks need to be held during parsing.
*
* The query part of the update is parsed to a CanonicalQuery, and the update part is parsed
* using the UpdateDriver.
*/
class ParsedUpdate {
MONGO_DISALLOW_COPYING(ParsedUpdate);
public:
/**
* Constructs a parsed update.
*
* The object pointed to by "request" must stay in scope for the life of the constructed
* ParsedUpdate.
*/
ParsedUpdate(OperationContext* txn, const UpdateRequest* request);
/**
* Parses the update request to a canonical query and an update driver. On success, the
* parsed update can be used to create a PlanExecutor for this update.
*/
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 UpdateRequest* getRequest() const;
/**
* Get a pointer to the update driver, the abstraction which both parses the update and
* is capable of applying mods / computing damages.
*/
UpdateDriver* getDriver();
/**
* Is this update 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:
/**
* Parses the query portion of the update request.
*/
Status parseQuery();
/**
* Parses the update-descriptor portion of the update request.
*/
Status parseUpdate();
// Unowned pointer to the transactional context.
OperationContext* _txn;
// Unowned pointer to the request object to process.
const UpdateRequest* const _request;
// Driver for processing updates on matched documents.
UpdateDriver _driver;
// 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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