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// extsort.h
/**
* Copyright (C) 2008 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 "../pch.h"
#include "jsobj.h"
#include "namespace-inl.h"
#include "curop-inl.h"
#include "../util/array.h"
namespace mongo {
/**
for sorting by BSONObj and attaching a value
*/
class BSONObjExternalSorter : boost::noncopyable {
public:
typedef pair<BSONObj,DiskLoc> Data;
private:
static BSONObj extSortOrder;
static int extSortComp( const void *lv, const void *rv ) {
RARELY killCurrentOp.checkForInterrupt();
_compares++;
Data * l = (Data*)lv;
Data * r = (Data*)rv;
int cmp = l->first.woCompare( r->first , extSortOrder );
if ( cmp )
return cmp;
return l->second.compare( r->second );
};
class FileIterator : boost::noncopyable {
public:
FileIterator( string file );
~FileIterator();
bool more();
Data next();
private:
MemoryMappedFile _file;
char * _buf;
char * _end;
};
class MyCmp {
public:
MyCmp( const BSONObj & order = BSONObj() ) : _order( order ) {}
bool operator()( const Data &l, const Data &r ) const {
RARELY killCurrentOp.checkForInterrupt();
_compares++;
int x = l.first.woCompare( r.first , _order );
if ( x )
return x < 0;
return l.second.compare( r.second ) < 0;
};
private:
BSONObj _order;
};
public:
typedef FastArray<Data> InMemory;
class Iterator : boost::noncopyable {
public:
Iterator( BSONObjExternalSorter * sorter );
~Iterator();
bool more();
Data next();
private:
MyCmp _cmp;
vector<FileIterator*> _files;
vector< pair<Data,bool> > _stash;
InMemory * _in;
InMemory::iterator _it;
};
BSONObjExternalSorter( const BSONObj & order = BSONObj() , long maxFileSize = 1024 * 1024 * 100 );
~BSONObjExternalSorter();
void add( const BSONObj& o , const DiskLoc & loc );
void add( const BSONObj& o , int a , int b ) {
add( o , DiskLoc( a , b ) );
}
/* call after adding values, and before fetching the iterator */
void sort();
auto_ptr<Iterator> iterator() {
uassert( 10052 , "not sorted" , _sorted );
return auto_ptr<Iterator>( new Iterator( this ) );
}
int numFiles() {
return _files.size();
}
long getCurSizeSoFar() { return _curSizeSoFar; }
void hintNumObjects( long long numObjects ) {
if ( numObjects < _arraySize )
_arraySize = (int)(numObjects + 100);
}
private:
void _sortInMem();
void sort( string file );
void finishMap();
BSONObj _order;
long _maxFilesize;
path _root;
int _arraySize;
InMemory * _cur;
long _curSizeSoFar;
list<string> _files;
bool _sorted;
static unsigned long long _compares;
};
}
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