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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 <string>
#include "mongo/base/status.h"
#include "mongo/db/hasher.h" // For HashSeed.
#include "mongo/db/index/index_descriptor.h"
#include "mongo/db/index/btree_access_method_internal.h"
#include "mongo/db/jsobj.h"
namespace mongo {
/**
* This is the access method for "hashed" indices.
*/
class HashAccessMethod : public BtreeBasedAccessMethod {
public:
using BtreeBasedAccessMethod::_descriptor;
HashAccessMethod(IndexDescriptor* descriptor);
virtual ~HashAccessMethod() { }
virtual Status newCursor(IndexCursor** out);
// This is a NO-OP.
virtual Status setOptions(const CursorOptions& options) {
return Status::OK();
}
/**
* Hashing function used by both this class and the cursors we create.
* Exposed for testing and so mongo/db/index_legacy.cpp can use it.
*/
static long long int makeSingleKey(const BSONElement& e, HashSeed seed, int v);
/**
* Exposed externally for testing purposes.
*/
static void getKeysImpl(const BSONObj& obj, const string& hashedField, HashSeed seed,
int hashVersion, bool isSparse, BSONObjSet* keys);
private:
virtual void getKeys(const BSONObj& obj, BSONObjSet* keys);
// Only one of our fields is hashed. This is the field name for it.
string _hashedField;
// _seed defaults to zero.
HashSeed _seed;
// _hashVersion defaults to zero.
int _hashVersion;
BSONObj _missingKey;
};
} // namespace mongo
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