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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 ModifierCompare : public ModifierInterface {
MONGO_DISALLOW_COPYING(ModifierCompare);
public:
enum ModifierCompareMode { MAX, MIN };
explicit ModifierCompare(ModifierCompareMode mode = MAX);
virtual ~ModifierCompare();
//
// Modifier interface implementation
//
/**
* A 'modExpr' is a BSONElement {<fieldname>: <value>} coming from a $set mod such as
* {$set: {<fieldname: <value>}}. init() extracts the field name and the value to be
* assigned to it from 'modExpr'. It returns OK if successful or a status describing
* the error.
*/
virtual Status init(const BSONElement& modExpr, const Options& opts,
bool* positional = NULL);
/**
* Looks up the field name in the sub-tree rooted at 'root', and binds, if necessary,
* the '$' field part using the 'matchedfield' number. prepare() returns OK and
* fills in 'execInfo' with information of whether this mod is a no-op on 'root' and
* whether it is an in-place candidate. Otherwise, returns a status describing the
* error.
*/
virtual Status prepare(mutablebson::Element root,
StringData matchedField,
ExecInfo* execInfo);
/**
* Applies the prepared mod over the element 'root' specified in the prepare()
* call. Returns OK if successful or a status describing the error.
*/
virtual Status apply() const;
/**
* Adds a log entry to logRoot corresponding to the operation applied here. Returns OK
* if successful or a status describing the error.
*/
virtual Status log(LogBuilder* logBuilder) const;
private:
// Compare mode: min/max
const ModifierCompareMode _mode;
// Access to each component of fieldName that's the target of this mod.
FieldRef _updatePath;
// 0 or index for $-positional in _updatePath.
size_t _pathReplacementPosition;
// Element of the mod expression.
BSONElement _val;
// The instance of the field in the provided doc. This state is valid after a
// prepare() was issued and until a log() is issued. The document this mod is
// being prepared against must be live throughout all the calls.
struct PreparedState;
std::unique_ptr<PreparedState> _preparedState;
};
} // namespace mongo
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