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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 <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/ops/modifier_interface.h"
namespace mongo {
class LogBuilder;
class ModifierInc : public ModifierInterface {
MONGO_DISALLOW_COPYING(ModifierInc);
public:
// TODO: This is a shortcut to implementing $mul by hijacking $inc. In the near future,
// we should consider either pulling $mul into its own operator, or creating a general
// purpose "numeric binary op" operator. Potentially, that operator could also subsume
// $bit (thought there are some subtleties, like that $bit can have multiple
// operations, and doing so with arbirary math operations introduces potential
// associativity difficulties). At the very least, if this mechanism is retained, then
// this class should be renamed at some point away from ModifierInc.
enum ModifierIncMode {
MODE_INC,
MODE_MUL
};
ModifierInc(ModifierIncMode mode = MODE_INC);
virtual ~ModifierInc();
/**
* A 'modExpr' is a BSONElement {<fieldname>: <value>} coming from a $inc mod such as
* {$inc: {<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);
/** Evaluates the validity of applying $inc to the identified node, and computes
* effects, handling upcasting and overflow as necessary.
*/
virtual Status prepare(mutablebson::Element root,
const StringData& matchedField,
ExecInfo* execInfo);
/** Updates the node passed in prepare with the results of the $inc */
virtual Status apply() const;
/** Converts the result of the $inc into an equivalent $set under logRoot */
virtual Status log(LogBuilder* logBuilder) const;
private:
const ModifierIncMode _mode;
// Access to each component of fieldName that's the target of this mod.
FieldRef _fieldRef;
// 0 or index for $-positional in _fieldRef.
size_t _posDollar;
// Element of the $set expression.
SafeNum _val;
struct PreparedState;
scoped_ptr<PreparedState> _preparedState;
};
} // namespace mongo
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