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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 <boost/scoped_ptr.hpp>
#include <string>
#include "mongo/base/disallow_copying.h"
#include "mongo/bson/mutable/element.h"
#include "mongo/db/field_ref.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/ops/modifier_interface.h"
namespace mongo {
class LogBuilder;
class ModifierPop : public ModifierInterface {
MONGO_DISALLOW_COPYING(ModifierPop);
public:
ModifierPop();
virtual ~ModifierPop();
/**
* The format of this modifier ($pop) is {<fieldname>: <value>}.
* If the value is number and greater than -1 then an element is removed from the bottom,
* otherwise the top. Currently the value can be any anything but we document
* the use of the numbers "1, -1" only.
*
* Ex. $pop: {'a':1} will remove the last item from this array: [1,2,3] -> [1,2]
*/
virtual Status init(const BSONElement& modExpr, const Options& opts);
virtual Status prepare(mutablebson::Element root,
const StringData& matchedField,
ExecInfo* execInfo);
virtual Status apply() const;
virtual Status log(LogBuilder* logBuilder) const;
private:
// Access to each component of fieldName that's the target of this mod.
FieldRef _fieldRef;
// 0 or index for $-positional in _fieldRef.
size_t _positionalPathIndex;
// element position to remove from
bool _fromTop;
// The instance of the field in the provided doc.
// This data is valid after prepare, for use by log and apply
struct PreparedState;
scoped_ptr<PreparedState> _preparedState;
};
} // namespace mongo
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