/**
* 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 .
*
* 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
#include
#include "mongo/base/disallow_copying.h"
#include "mongo/base/status.h"
namespace mongo {
class StorageEngineLockFile {
MONGO_DISALLOW_COPYING(StorageEngineLockFile);
public:
/**
* Checks existing lock file, if present, to see if it contains data from a previous
* unclean shutdown. A clean shutdown should have produced a zero length lock file.
* Uses open() to read existing lock file or create new file.
* Uses boost::filesystem to check lock file so may throw boost::exception.
*/
StorageEngineLockFile(const std::string& dbpath);
virtual ~StorageEngineLockFile();
/**
* Returns the path to the lock file.
*/
std::string getFilespec() const;
/**
* Returns true if lock file was not zeroed out due to previous unclean shutdown.
* This state is evaluated at object initialization to allow storage engine
* to make decisions on recovery based on this information after open() has been called.
*/
bool createdByUncleanShutdown() const;
/**
* Opens and locks 'mongod.lock' in 'dbpath' directory.
*/
Status open();
/**
* Closes lock file handles.
*/
void close();
/**
* Writes current process ID to file.
* Fails if lock file has not been opened.
*/
Status writePid();
/**
* Truncates file contents and releases file locks.
*/
void clearPidAndUnlock();
private:
std::string _dbpath;
std::string _filespec;
bool _uncleanShutdown;
class LockFileHandle;
std::unique_ptr _lockFileHandle;
};
} // namespace mongo