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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/>.
*
*    As a special exception, the copyright holders give permission to link the
*    code of portions of this program with the OpenSSL library under certain
*    conditions as described in each individual source file and distribute
*    linked combinations including the program with the OpenSSL library. You
*    must comply with the GNU Affero General Public License in all respects for
*    all of the code used other than as permitted herein. If you modify file(s)
*    with this exception, you may extend this exception to your version of the
*    file(s), but you are not obligated to do so. If you do not wish to do so,
*    delete this exception statement from your version. If you delete this
*    exception statement from all source files in the program, then also delete
*    it in the license file.
*/

#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/index_access_method.h"
#include "mongo/db/jsobj.h"

namespace mongo {

/**
 * This is the access method for "hashed" indices.
 */
class HashAccessMethod : public IndexAccessMethod {
public:
    HashAccessMethod(IndexCatalogEntry* btreeState, SortedDataInterface* btree);

private:
    virtual void getKeys(const BSONObj& obj, BSONObjSet* keys) const;

    // Only one of our fields is hashed.  This is the field name for it.
    std::string _hashedField;

    // _seed defaults to zero.
    HashSeed _seed;

    // _hashVersion defaults to zero.
    int _hashVersion;

    BSONObj _missingKey;
};

}  // namespace mongo