1 2 /** 3 * Copyright (C) 2018-present MongoDB, Inc. 4 * 5 * This program is free software: you can redistribute it and/or modify 6 * it under the terms of the Server Side Public License, version 1, 7 * as published by MongoDB, Inc. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * Server Side Public License for more details. 13 * 14 * You should have received a copy of the Server Side Public License 15 * along with this program. If not, see 16 * <http://www.mongodb.com/licensing/server-side-public-license>. 17 * 18 * As a special exception, the copyright holders give permission to link the 19 * code of portions of this program with the OpenSSL library under certain 20 * conditions as described in each individual source file and distribute 21 * linked combinations including the program with the OpenSSL library. You 22 * must comply with the Server Side Public License in all respects for 23 * all of the code used other than as permitted herein. If you modify file(s) 24 * with this exception, you may extend this exception to your version of the 25 * file(s), but you are not obligated to do so. If you do not wish to do so, 26 * delete this exception statement from your version. If you delete this 27 * exception statement from all source files in the program, then also delete 28 * it in the license file. 29 */ 30 31 #pragma once 32 33 #include "mongo/db/update/modifier_node.h" 34 #include "mongo/stdx/memory.h" 35 36 namespace mongo { 37 38 /** 39 * Represents the application of $max or $min to the value at the end of a path. 40 */ 41 class CompareNode : public ModifierNode { 42 public: 43 enum class CompareMode { kMax, kMin }; 44 CompareNode(CompareMode mode)45 explicit CompareNode(CompareMode mode) : _mode(mode) {} 46 47 Status init(BSONElement modExpr, const boost::intrusive_ptr<ExpressionContext>& expCtx) final; 48 clone()49 std::unique_ptr<UpdateNode> clone() const final { 50 return stdx::make_unique<CompareNode>(*this); 51 } 52 53 void setCollator(const CollatorInterface* collator) final; 54 55 protected: 56 ModifyResult updateExistingElement(mutablebson::Element* element, 57 std::shared_ptr<FieldRef> elementPath) const final; 58 void setValueForNewElement(mutablebson::Element* element) const final; 59 allowCreation()60 bool allowCreation() const final { 61 return true; 62 } 63 canSetObjectValue()64 bool canSetObjectValue() const final { 65 return true; 66 } 67 68 private: 69 CompareMode _mode; 70 BSONElement _val; 71 const CollatorInterface* _collator = nullptr; 72 }; 73 74 } // namespace mongo 75