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/**
* 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 <vector>
#include "mongo/base/status.h"
#include "mongo/db/diskloc.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/index/btree_interface.h"
#include "mongo/db/index/index_cursor.h"
#include "mongo/db/index/index_descriptor.h"
namespace mongo {
class BtreeIndexCursor : public IndexCursor {
public:
virtual ~BtreeIndexCursor();
bool isEOF() const;
// See nasty comment in .cpp
virtual DiskLoc getBucket() const;
virtual int getKeyOfs() const;
/**
* Called from btree.cpp when we're about to delete a Btree bucket.
*/
static void aboutToDeleteBucket(const DiskLoc& bucket);
virtual Status setOptions(const CursorOptions& options);
virtual Status seek(const BSONObj& position);
// Btree-specific seeking functions.
Status seek(const vector<const BSONElement*>& position,
const vector<bool>& inclusive);
Status skip(const BSONObj &keyBegin, int keyBeginLen, bool afterKey,
const vector<const BSONElement*>& keyEnd,
const vector<bool>& keyEndInclusive);
virtual BSONObj getKey() const;
virtual DiskLoc getValue() const;
virtual void next();
virtual Status savePosition();
virtual Status restorePosition();
virtual string toString();
private:
// We keep the constructor private and only allow the AM to create us.
friend class BtreeAccessMethod;
// For handling bucket deletion.
static unordered_set<BtreeIndexCursor*> _activeCursors;
static SimpleMutex _activeCursorsMutex;
// Go forward by default.
BtreeIndexCursor(IndexDescriptor *descriptor, Ordering ordering, BtreeInterface *interface);
void skipUnusedKeys();
bool isSavedPositionValid();
// Move to the next/prev. key. Used by normal getNext and also skipping unused keys.
void advance(const char* caller);
// For saving/restoring position.
BSONObj _savedKey;
DiskLoc _savedLoc;
BSONObj _emptyObj;
int _direction;
IndexDescriptor* _descriptor;
Ordering _ordering;
BtreeInterface* _interface;
// What are we looking at RIGHT NOW? We look at a bucket.
DiskLoc _bucket;
// And we look at an offset in the bucket.
int _keyOffset;
};
} // namespace mongo
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