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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 <set>
#include "mongo/base/disallow_copying.h"
#include "mongo/db/field_ref.h"
namespace mongo {
/**
* A FieldRefSet holds a set of FieldRefs's that do not conflict with one another, that is,
* they target different subtrees of a given document. Two fieldRef's would conflict if they
* are equal or one is prefix of the other.
*/
class FieldRefSet {
MONGO_DISALLOW_COPYING(FieldRefSet);
public:
FieldRefSet();
/**
* Returns true if the field 'toInsert' can be added in the set without
* conflicts. Otwerwise returns false and fill in '*conflict' with the field 'toInsert'
* clashed with.
*
* There is no ownership transfer of 'toInsert'. The caller is responsible for
* maintaining it alive for as long as the FieldRefSet is so. By the same token
* 'conflict' can only be referred to while the FieldRefSet can.
*/
bool insert(const FieldRef* toInsert, const FieldRef** conflict);
private:
struct FieldRefPtrLessThan {
bool operator()(const FieldRef* lhs, const FieldRef* rhs) const;
};
typedef std::set<const FieldRef*, FieldRefPtrLessThan> FieldSet;
// A set of field_ref pointers, none of which is owned here.
FieldSet _fieldSet;
};
} // namespace mongo
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