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/**
* Copyright (C) 2019-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* 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 Server Side 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 "mongo/platform/basic.h"
namespace mongo {
class AddToSetNode;
class ArithmeticNode;
class BitNode;
class CompareNode;
class ConflictPlaceholderNode;
class CurrentDateNode;
class PopNode;
class PullAllNode;
class PullNode;
class PushNode;
class RenameNode;
class SetElementNode;
class SetNode;
class UnsetNode;
class UpdateArrayNode;
class UpdateObjectNode;
/**
* This is a base class to allow for traversal of an update tree. It implements the visitor
* pattern, in which every derived class from update node implements an acceptVisitor() method,
* which simply calls the appropriate visit() method on the derived UpdateNodeVisitor class. The
* derived class can do whatever it needs to do for each specific node type in the corresponding
* visit() method.
* Derived classes are responsible for making the recursive calls to visit() if they wish
* to visit all the nodes in the update node tree. UpdateNodeVisitor's purpose is not actually to
* ensure that every node in the tree is visited, but rather to handle dynamic dispatch without
* having to add virtual methods to the UpdateNode interface itself.
*/
class UpdateNodeVisitor {
public:
virtual ~UpdateNodeVisitor() = default;
virtual void visit(AddToSetNode*) = 0;
virtual void visit(ArithmeticNode*) = 0;
virtual void visit(BitNode*) = 0;
virtual void visit(CompareNode*) = 0;
virtual void visit(ConflictPlaceholderNode*) = 0;
virtual void visit(CurrentDateNode*) = 0;
virtual void visit(PopNode*) = 0;
virtual void visit(PullAllNode*) = 0;
virtual void visit(PullNode*) = 0;
virtual void visit(PushNode*) = 0;
virtual void visit(RenameNode*) = 0;
virtual void visit(SetElementNode*) = 0;
virtual void visit(SetNode*) = 0;
virtual void visit(UnsetNode*) = 0;
virtual void visit(UpdateArrayNode*) = 0;
virtual void visit(UpdateObjectNode*) = 0;
};
} // namespace mongo
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