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 #include "mongo/platform/basic.h"
32 
33 #include "mongo/db/update/unset_node.h"
34 
35 #include "mongo/db/update/storage_validation.h"
36 
37 namespace mongo {
38 
init(BSONElement modExpr,const boost::intrusive_ptr<ExpressionContext> & expCtx)39 Status UnsetNode::init(BSONElement modExpr, const boost::intrusive_ptr<ExpressionContext>& expCtx) {
40     // Note that we don't need to store modExpr, because $unset does not do anything with its value.
41     invariant(modExpr.ok());
42     return Status::OK();
43 }
44 
updateExistingElement(mutablebson::Element * element,std::shared_ptr<FieldRef> elementPath) const45 ModifierNode::ModifyResult UnsetNode::updateExistingElement(
46     mutablebson::Element* element, std::shared_ptr<FieldRef> elementPath) const {
47     auto parent = element->parent();
48 
49     invariant(parent.ok());
50     if (!parent.isType(BSONType::Array)) {
51         invariantOK(element->remove());
52     } else {
53         // Special case: An $unset on an array element sets it to null instead of removing it from
54         // the array.
55         invariantOK(element->setValueNull());
56     }
57 
58     return ModifyResult::kNormalUpdate;
59 }
60 
validateUpdate(mutablebson::ConstElement updatedElement,mutablebson::ConstElement leftSibling,mutablebson::ConstElement rightSibling,std::uint32_t recursionLevel,ModifyResult modifyResult) const61 void UnsetNode::validateUpdate(mutablebson::ConstElement updatedElement,
62                                mutablebson::ConstElement leftSibling,
63                                mutablebson::ConstElement rightSibling,
64                                std::uint32_t recursionLevel,
65                                ModifyResult modifyResult) const {
66     invariant(modifyResult == ModifyResult::kNormalUpdate);
67 
68     // We only need to check the left and right sibling to see if the removed element was part of a
69     // now invalid DBRef.
70     const bool doRecursiveCheck = false;
71     const uint32_t recursionLevelForCheck = 0;
72 
73     if (leftSibling.ok()) {
74         storage_validation::storageValid(leftSibling, doRecursiveCheck, recursionLevelForCheck);
75     }
76 
77     if (rightSibling.ok()) {
78         storage_validation::storageValid(rightSibling, doRecursiveCheck, recursionLevelForCheck);
79     }
80 }
81 
logUpdate(LogBuilder * logBuilder,StringData pathTaken,mutablebson::Element element,ModifyResult modifyResult) const82 void UnsetNode::logUpdate(LogBuilder* logBuilder,
83                           StringData pathTaken,
84                           mutablebson::Element element,
85                           ModifyResult modifyResult) const {
86     invariant(logBuilder);
87     invariant(modifyResult == ModifyResult::kNormalUpdate);
88     uassertStatusOK(logBuilder->addToUnsets(pathTaken));
89 }
90 
91 }  // namespace mongo
92