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mongodb/s/shardkey.cpp
2009-02-17 15:34:52 -05:00

98 lines
3.0 KiB
C++

// shardkey.cpp
/**
* 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/>.
*/
#include "stdafx.h"
#include "shard.h"
#include "../db/jsobj.h"
/**
TODO: this only works with numbers right now
this is very temporary, need to make work with anything
*/
namespace mongo {
ShardKey::ShardKey( BSONObj fieldsAndOrder ) : _fieldsAndOrder( fieldsAndOrder ){
if ( _fieldsAndOrder.nFields() > 0 ){
_init();
}
else {
_fieldName = 0;
}
}
void ShardKey::init( BSONObj fieldsAndOrder ){
_fieldsAndOrder = fieldsAndOrder;
_init();
}
void ShardKey::_init(){
_fieldName = _fieldsAndOrder.firstElement().fieldName();
uassert( "shard key only supports 1 field right now" , 1 == _fieldsAndOrder.nFields() );
uassert( "shard key has to be a number right now" , _fieldsAndOrder.firstElement().isNumber() );
}
void ShardKey::globalMin( BSONObjBuilder& b ){
uassert( "not valid yet" , _fieldName );
b << _fieldName << (int)(-0xfffffff);
}
void ShardKey::globalMax( BSONObjBuilder& b ){
uassert( "not valid yet" , _fieldName );
b << _fieldName << (int)(0xfffffff);
}
int ShardKey::compare( BSONObj& lObject , BSONObj& rObject ){
uassert( "not valid yet" , _fieldName );
BSONElement lElement = lObject[ _fieldsAndOrder.firstElement().fieldName() ];
uassert( "left key doesn't have the shard key" , ! lElement.eoo() );
uassert( "left key isn't number" , lElement.isNumber() );
BSONElement rElement = rObject[ _fieldsAndOrder.firstElement().fieldName() ];
uassert( "right key doesn't have the shard key" , ! rElement.eoo() );
uassert( "right key isn't number" , rElement.isNumber() );
if ( lElement.number() < rElement.number() )
return -1;
if ( lElement.number() > rElement.number() )
return 1;
return 0;
}
void shardKeyTest(){
ShardKey k( BSON( "key" << 1 ) );
BSONObj min = k.globalMin();
BSONObj max = k.globalMax();
log(3) << "globalMin: " << min << endl;
log(3) << "globalMax: " << max << endl;
assert( k.compare( min , max ) < 0 );
assert( k.compare( max , min ) > 0 );
assert( k.compare( min , min ) == 0 );
}
} // namespace mongo