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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/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,
bool* positional = NULL);
virtual Status prepare(mutablebson::Element root,
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;
std::unique_ptr<PreparedState> _preparedState;
};
} // namespace mongo
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