/**
* Copyright (C) 2017 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see .
*
* 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 GNU Affero General 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/clonable_ptr.h"
#include "mongo/db/update/modifier_node.h"
#include "mongo/stdx/memory.h"
namespace mongo {
/**
* An ArrayCullingNode represents an update modifier that removes elements from an array that match
* a predicate (condensing the array in the process), such as $pull and $pullAll. Modifiers with
* this behavior all use the same apply() logic (implemented in this class), which uses a
* subclass-supplied ElementMatcher to determine which array elements should be removed. The init
* method for each subclass must populate _matcher with an ElementMatcher implementation.
*/
class ArrayCullingNode : public ModifierNode {
public:
ModifyResult updateExistingElement(mutablebson::Element* element,
std::shared_ptr elementPath) const final;
void validateUpdate(mutablebson::ConstElement updatedElement,
mutablebson::ConstElement leftSibling,
mutablebson::ConstElement rightSibling,
std::uint32_t recursionLevel,
ModifyResult modifyResult) const final;
void setCollator(const CollatorInterface* collator) final {
_matcher->setCollator(collator);
}
protected:
/**
* ArrayCullingNode::apply() uses an ElementMatcher to determine which array elements meet the
* $pull condition. The different subclasses of ElementMatcher implement the different kinds of
* checks that can be used for a $pull operation.
*/
class ElementMatcher {
public:
virtual ~ElementMatcher() = default;
virtual std::unique_ptr clone() const = 0;
virtual bool match(const mutablebson::ConstElement& element) = 0;
virtual void setCollator(const CollatorInterface* collator) = 0;
};
clonable_ptr _matcher;
};
} // namespace mongo