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// extent_manager.h
/**
* Copyright (C) 2013 10gen 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/>.
*/
#pragma once
#include <string>
#include <vector>
#include <boost/filesystem/path.hpp>
#include "mongo/base/status.h"
#include "mongo/base/string_data.h"
#include "mongo/db/diskloc.h"
namespace mongo {
class DataFile;
/**
* ExtentManager basics
* - one per database
* - responsible for managing <db>.# files
* - NOT responsible for .ns file
* - gives out extents
* - responsible for figuring out how to get a new extent
* - can use any method it wants to do so
* - this structure is NOT stored on disk
* - this class is NOT thread safe, locking should be above (for now)
*
* implementation:
* - ExtentManager holds a list of DataFile
*/
class ExtentManager {
MONGO_DISALLOW_COPYING( ExtentManager );
public:
ExtentManager( const StringData& dbname, const StringData& path, bool directoryPerDB );
~ExtentManager();
/**
* deletes all state and puts back to original state
*/
void reset();
/**
* opens all current files
*/
Status init();
size_t numFiles() const;
long long fileSize() const;
DataFile* getFile( int n, int sizeNeeded = 0, bool preallocateOnly = false );
DataFile* addAFile( int sizeNeeded, bool preallocateNextFile );
void preallocateAFile() { getFile( numFiles() , 0, true ); }// XXX-ERH
void flushFiles( bool sync );
/* allocate a new Extent
@param capped - true if capped collection
*/
Extent* createExtent( const char *ns, int approxSize, bool newCapped, bool enforceQuota );
/**
* @param loc - has to be for a specific Record
*/
Record* recordFor( const DiskLoc& loc ) const;
/**
* @param loc - has to be for a specific Record (not an Extent)
*/
Extent* extentFor( const DiskLoc& loc ) const;
/**
* @param loc - has to be for a specific Extent
*/
Extent* getExtent( const DiskLoc& loc, bool doSanityCheck = true ) const;
Extent* getNextExtent( Extent* ) const;
Extent* getPrevExtent( Extent* ) const;
// get(Next|Prev)Record follows the Record linked list
// these WILL cross Extent boundaries
// * @param loc - has to be the DiskLoc for a Record
DiskLoc getNextRecord( const DiskLoc& loc ) const;
DiskLoc getPrevRecord( const DiskLoc& loc ) const;
// does NOT traverse extent boundaries
DiskLoc getNextRecordInExtent( const DiskLoc& loc ) const;
DiskLoc getPrevRecordInExtent( const DiskLoc& loc ) const;
/**
* quantizes extent size to >= min + page boundary
*/
static int quantizeExtentSize( int size );
private:
const DataFile* _getOpenFile( int n ) const;
Extent* _createExtentInFile( int fileNo, DataFile* f,
const char* ns, int size, bool newCapped,
bool enforceQuota );
boost::filesystem::path fileName( int n ) const;
// -----
std::string _dbname; // i.e. "test"
std::string _path; // i.e. "/data/db"
bool _directoryPerDB;
// must be in the dbLock when touching this (and write locked when writing to of course)
// however during Database object construction we aren't, which is ok as it isn't yet visible
// to others and we are in the dbholder lock then.
std::vector<DataFile*> _files;
};
}
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