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/bson/mutable/document.h" 34 #include "mongo/bson/mutable/element.h" 35 #include "mongo/db/bson/dotted_path_support.h" 36 #include "mongo/db/jsobj.h" 37 #include "mongo/db/query/collation/collator_interface.h" 38 39 namespace mongo { 40 41 // Extracts the value for 'pattern' for both 'lhs' and 'rhs' and return true if 'lhs' < 42 // 'rhs'. We expect that both 'lhs' and 'rhs' be key patterns. 43 struct PatternElementCmp { 44 PatternElementCmp() = default; 45 PatternElementCmpPatternElementCmp46 PatternElementCmp(const BSONObj& pattern, const CollatorInterface* collator) 47 : sortPattern(pattern), useWholeValue(pattern.hasField("")), collator(collator) {} 48 operatorPatternElementCmp49 bool operator()(const mutablebson::Element& lhs, const mutablebson::Element& rhs) const { 50 namespace dps = ::mongo::dotted_path_support; 51 if (useWholeValue) { 52 const int comparedValue = lhs.compareWithElement(rhs, collator, false); 53 54 const bool reversed = (sortPattern.firstElement().number() < 0); 55 56 return (reversed ? comparedValue > 0 : comparedValue < 0); 57 } else { 58 // TODO: Push on to mutable in the future, and to support non-contiguous Elements. 59 BSONObj lhsObj = 60 lhs.getType() == Object ? lhs.getValueObject() : lhs.getValue().wrap(""); 61 BSONObj rhsObj = 62 rhs.getType() == Object ? rhs.getValueObject() : rhs.getValue().wrap(""); 63 64 BSONObj lhsKey = dps::extractElementsBasedOnTemplate(lhsObj, sortPattern, true); 65 BSONObj rhsKey = dps::extractElementsBasedOnTemplate(rhsObj, sortPattern, true); 66 67 return lhsKey.woCompare(rhsKey, sortPattern, false, collator) < 0; 68 } 69 } 70 71 BSONObj sortPattern; 72 bool useWholeValue = true; 73 const CollatorInterface* collator = nullptr; 74 }; 75 76 } // namespace mongo 77