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/**
* Copyright (C) 2012 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 "mongo/db/intervalbtreecursor.h"
#include "mongo/db/btree.h"
#include "mongo/db/kill_current_op.h"
#include "mongo/db/namespace_details-inl.h"
#include "mongo/db/pdfile.h"
namespace mongo {
/**
* Advance 'loc' until it does not reference an unused key, or the end of the btree is reached.
*/
static void skipUnused( BtreeKeyLocation* loc ) {
// While loc points to an unused key ...
while( !loc->bucket.isNull() &&
loc->bucket.btree<V1>()->k( loc->pos ).isUnused() ) {
// ... advance loc to the next key in the btree.
loc->bucket = loc->bucket.btree<V1>()->advance( loc->bucket,
loc->pos,
1,
__FUNCTION__ );
}
}
IntervalBtreeCursor* IntervalBtreeCursor::make( NamespaceDetails* namespaceDetails,
const IndexDetails& indexDetails,
const BSONObj& lowerBound,
bool lowerBoundInclusive,
const BSONObj& upperBound,
bool upperBoundInclusive ) {
if ( indexDetails.version() != 1 ) {
// Only v1 indexes are supported.
return NULL;
}
auto_ptr<IntervalBtreeCursor> ret( new IntervalBtreeCursor( namespaceDetails,
indexDetails,
lowerBound,
lowerBoundInclusive,
upperBound,
upperBoundInclusive ) );
ret->init();
return ret.release();
}
IntervalBtreeCursor::IntervalBtreeCursor( NamespaceDetails* namespaceDetails,
const IndexDetails& indexDetails,
const BSONObj& lowerBound,
bool lowerBoundInclusive,
const BSONObj& upperBound,
bool upperBoundInclusive ) :
_namespaceDetails( *namespaceDetails ),
_indexNo( namespaceDetails->idxNo( indexDetails ) ),
_indexDetails( indexDetails ),
_ordering( Ordering::make( _indexDetails.keyPattern() ) ),
_lowerBound( lowerBound ),
_lowerBoundInclusive( lowerBoundInclusive ),
_upperBound( upperBound ),
_upperBoundInclusive( upperBoundInclusive ),
_currRecoverable( _indexDetails, _ordering, _curr ),
_nscanned(),
_multikeyFlag() {
}
void IntervalBtreeCursor::init() {
_multikeyFlag = _namespaceDetails.isMultikey( _indexNo );
_curr = locateKey( _lowerBound, !_lowerBoundInclusive );
skipUnused( &_curr );
relocateEnd();
if ( ok() ) {
_nscanned = 1;
}
}
bool IntervalBtreeCursor::ok() {
return !_curr.bucket.isNull();
}
DiskLoc IntervalBtreeCursor::currLoc() {
if ( eof() ) {
return DiskLoc();
}
return _curr.bucket.btree<V1>()->keyNode( _curr.pos ).recordLoc;
}
bool IntervalBtreeCursor::advance() {
RARELY killCurrentOp.checkForInterrupt();
if ( eof() ) {
return false;
}
// Advance _curr to the next key in the btree.
_curr.bucket = _curr.bucket.btree<V1>()->advance( _curr.bucket,
_curr.pos,
1,
__FUNCTION__ );
skipUnused( &_curr );
if ( _curr == _end ) {
// _curr has reached _end, so iteration is complete.
_curr.bucket.Null();
}
else {
++_nscanned;
}
return ok();
}
BSONObj IntervalBtreeCursor::currKey() const {
if ( _curr.bucket.isNull() ) {
return BSONObj();
}
return _curr.bucket.btree<V1>()->keyNode( _curr.pos ).key.toBson();
}
void IntervalBtreeCursor::aboutToDeleteBucket( const DiskLoc& b ) {
if ( b == _curr.bucket ) {
_currRecoverable.invalidateInitialLocation();
}
}
void IntervalBtreeCursor::noteLocation() {
_currRecoverable = LogicalBtreePosition( _indexDetails, _ordering, _curr );
_currRecoverable.init();
}
void IntervalBtreeCursor::checkLocation() {
_multikeyFlag = _namespaceDetails.isMultikey( _indexNo );
_curr = _currRecoverable.currentLocation();
skipUnused( &_curr );
relocateEnd();
}
bool IntervalBtreeCursor::getsetdup( DiskLoc loc ) {
// TODO _multikeyFlag may be set part way through an iteration by checkLocation(). In this
// case results returned earlier, when _multikeyFlag was false, will not be deduped. This
// is an old issue with all mongo btree cursor implementations.
return _multikeyFlag && !_dups.insert( loc.asUint64() ).second;
}
BSONObj IntervalBtreeCursor::prettyIndexBounds() const {
return BSON( "lower" << _lowerBound.replaceFieldNames( _indexDetails.keyPattern() ) <<
"upper" << _upperBound.replaceFieldNames( _indexDetails.keyPattern() ) );
}
BtreeKeyLocation IntervalBtreeCursor::locateKey( const BSONObj& key, bool afterKey ) {
bool found;
BtreeKeyLocation ret;
// To find the first btree location equal to the specified key, specify a record location of
// minDiskLoc, which is below any actual Record location. To find the first btree location
// greater than the specified key, specify a record location of maxDiskLoc, which is above
// any actual Record location.
DiskLoc targetRecord = afterKey ? maxDiskLoc : minDiskLoc;
// Find the requested location in the btree.
ret.bucket = _indexDetails.head.btree<V1>()->locate( _indexDetails,
_indexDetails.head,
key,
_ordering,
ret.pos,
found,
targetRecord,
1 );
return ret;
}
void IntervalBtreeCursor::relocateEnd() {
if ( eof() ) {
return;
}
// If the current key is above the upper bound ...
int32_t cmp = currKey().woCompare( _upperBound, _ordering, false );
if ( cmp > 0 || ( cmp == 0 && !_upperBoundInclusive ) ) {
// ... then iteration is complete.
_curr.bucket.Null();
return;
}
// Otherwise, relocate _end.
_end = locateKey( _upperBound, _upperBoundInclusive );
skipUnused( &_end );
}
} // namespace mongo
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