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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/db/pipeline/expression_context.h"
#include "mongo/db/update/update_node.h"
namespace mongo {
/**
* A leaf node in the prefix tree of update modifier expressions, representing an update to the
* value at the end of a path. See comment in class definition of UpdateNode for more details.
*/
class UpdateLeafNode : public UpdateNode {
public:
explicit UpdateLeafNode(Context context = Context::kAll) : UpdateNode(Type::Leaf, context) {}
/**
* Initializes the leaf node with the value in 'modExpr'. 'modExpr' is a single modifier
* expression in the update expression. For example, if the update expression is root = {$set:
* {'a.b': 5, c: 6}, $inc: {'a.c': 1}}, then a single modifier expression would be
* root["$set"]["a.b"]. Returns a non-OK status if the value in 'modExpr' is invalid for the
* type of leaf node. 'modExpr' must not be empty.
*
* Some leaf nodes require an ExpressionContext during initialization. For example, $pull
* requires an ExpressionContext to construct a MatchExpression that will be used for applying
* updates across multiple documents.
*/
virtual Status init(BSONElement modExpr,
const boost::intrusive_ptr<ExpressionContext>& expCtx) = 0;
/* Check if it would be possible to create the path at 'pathToCreate' but don't actually create
* it. If 'element' is not an embedded object or array (e.g., we are trying to create path
* "a.b.c" in the document {a: 1}) or 'element' is an array but the first component in
* 'pathToCreate' is not an array index (e.g., the path "a.b.c" in the document
* {a: [{b: 1}, {b: 2}]}), then this function throws a AssertionException with
* ErrorCode::PathNotViable. Otherwise, this function is a no-op.
*
* With the exception of $unset, update modifiers that do not create nonexistent paths ($pop,
* $pull, $pullAll) still generate an error when it is not possible to create the path.
*/
static void checkViability(mutablebson::Element element,
const FieldRef& pathToCreate,
const FieldRef& pathTaken);
};
} // namespace mongo
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