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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 <memory>
#include "mongo/base/disallow_copying.h"
#include "mongo/base/status.h"
#include "mongo/db/ops/update_driver.h"
#include "mongo/db/ops/update_result.h"
namespace mongo {
class CanonicalQuery;
class OpDebug;
class TransactionExperiment;
class UpdateRequest;
/**
* Implementation of the processing of an update operation in a mongod.
*
* The executor has two important methods, prepare() and execute(). The prepare() method can
* run without locks, and does whatever parsing and precomputation can be done without access to
* database data. The execute method performs the update, but the caller must already hold the
* appropriate database lock.
*
* Expected usage is approximately:
* UpdateRequest request(...);
* // configure request
* UpdateExecutor executor(&request, opDebug);
* uassertStatusOK(executor.prepare());
* // Get locks, get ready to execute.
* try {
* UpdateResult res = executor.execute();
* }
* catch (const DBException& ex) {
* // Error handling.
* }
*/
class UpdateExecutor {
MONGO_DISALLOW_COPYING(UpdateExecutor);
public:
/**
* Constructs an update executor.
*
* The objects pointed to by "request" and "opDebug" must stay in scope for the life of the
* constructed executor.
*/
UpdateExecutor(const UpdateRequest* request, OpDebug* opDebug);
~UpdateExecutor();
/**
* Performs preparatory work that does not require database locks.
*
* Returns Status::OK() on success. Other results indicate that the executor will not run
* correctly, and should be abandoned.
*
* Calling prepare() is optional. It is available for situations in which the user
* wishes to do as much work as possible before acquiring database locks.
*/
Status prepare();
/**
* Execute an update. Requires the caller to hold the database lock on the
* appropriate resources for the request.
*/
UpdateResult execute(TransactionExperiment* txn, Database* db);
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 request object that this executor will process.
const UpdateRequest* const _request;
/// Unowned pointer to the opdebug object that this executor will populate with debug data.
OpDebug* const _opDebug;
/// 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::auto_ptr<CanonicalQuery> _canonicalQuery;
/// Flag indicating if the query has been successfully parsed.
bool _isQueryParsed;
/// Flag indicatin gif the update description has been successfully parsed.
bool _isUpdateParsed;
};
} // namespace mongo
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