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/**
* Copyright (C) 2018-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/base/status.h"
#include "mongo/bson/mutable/document.h"
namespace mongo {
/**
* Previously, there were multiple supported versions of the update language.
*/
enum class UpdateSemantics {
// The update system introduced in v3.6, and is the only supported system. When a single update
// adds multiple fields, those fields are added in lexicographic order by field name. This
// system introduces support for arrayFilters and $[] syntax.
kUpdateNode = 1,
// Must be last.
kNumUpdateSemantics
};
/** LogBuilder abstracts away some of the details of producing a properly constructed oplog
* update entry. It manages separate regions into which it accumulates $set and $unset
* operations, and distinguishes object replacement style oplog generation from
* $set/$unset style generation and prevents admixture.
*/
class LogBuilder {
public:
static constexpr StringData kUpdateSemanticsFieldName = "$v"_sd;
/** Construct a new LogBuilder. Log entries will be recorded as new children under the
* 'logRoot' Element, which must be of type mongo::Object and have no children.
*/
inline LogBuilder(mutablebson::Element logRoot)
: _logRoot(logRoot),
_objectReplacementAccumulator(_logRoot),
_setAccumulator(_logRoot.getDocument().end()),
_unsetAccumulator(_setAccumulator),
_updateSemantics(_setAccumulator) {
dassert(logRoot.isType(mongo::Object));
dassert(!logRoot.hasChildren());
}
/** Return the Document to which the logging root belongs. */
inline mutablebson::Document& getDocument() {
return _logRoot.getDocument();
}
/** Add the given Element as a new entry in the '$set' section of the log. If a $set
* section does not yet exist, it will be created. If this LogBuilder is currently
* configured to contain an object replacement, the request to add to the $set section
* will return an Error.
*/
Status addToSets(mutablebson::Element elt);
/**
* Convenience method which calls addToSets after
* creating a new Element to wrap the SafeNum value.
*
* If any problem occurs then the operation will stop and return that error Status.
*/
Status addToSets(StringData name, const SafeNum& val);
/**
* Convenience method which calls addToSets after
* creating a new Element to wrap the old one.
*
* If any problem occurs then the operation will stop and return that error Status.
*/
Status addToSetsWithNewFieldName(StringData name, const mutablebson::Element val);
/**
* Convenience method which calls addToSets after
* creating a new Element to wrap the old one.
*
* If any problem occurs then the operation will stop and return that error Status.
*/
Status addToSetsWithNewFieldName(StringData name, const BSONElement& val);
/** Add the given path as a new entry in the '$unset' section of the log. If an
* '$unset' section does not yet exist, it will be created. If this LogBuilder is
* currently configured to contain an object replacement, the request to add to the
* $unset section will return an Error.
*/
Status addToUnsets(StringData path);
/**
* Add a "$v" field to the log. Fails if there is already a "$v" field.
*/
Status setUpdateSemantics(UpdateSemantics updateSemantics);
/** Obtain, via the out parameter 'outElt', a pointer to the mongo::Object type Element
* to which the components of an object replacement should be recorded. It is an error
* to call this if any Elements have been added by calling either addToSets or
* addToUnsets, and attempts to do so will return a non-OK Status. Similarly, if there
* is already object replacement data recorded for this log, the call will fail.
*/
Status getReplacementObject(mutablebson::Element* outElt);
private:
// Returns true if the object replacement accumulator is valid and has children, false
// otherwise.
inline bool hasObjectReplacement() const;
inline Status addToSection(mutablebson::Element newElt,
mutablebson::Element* section,
const char* sectionName);
mutablebson::Element _logRoot;
mutablebson::Element _objectReplacementAccumulator;
mutablebson::Element _setAccumulator;
mutablebson::Element _unsetAccumulator;
mutablebson::Element _updateSemantics;
};
} // namespace mongo
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