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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.
*/
#include "mongo/platform/basic.h"
#include "mongo/db/pipeline/parsed_exclusion_projection.h"
#include "mongo/db/pipeline/document.h"
#include "mongo/db/pipeline/field_path.h"
#include "mongo/db/pipeline/value.h"
#include "mongo/stdx/memory.h"
namespace mongo {
namespace parsed_aggregation_projection {
Document ParsedExclusionProjection::serializeTransformation(
boost::optional<ExplainOptions::Verbosity> explain) const {
return _root->serialize(explain);
}
Document ParsedExclusionProjection::applyProjection(const Document& inputDoc) const {
return _root->applyToDocument(inputDoc);
}
void ParsedExclusionProjection::parse(const BSONObj& spec, ExclusionNode* node, size_t depth) {
bool idSpecified = false;
for (auto elem : spec) {
const auto fieldName = elem.fieldNameStringData();
// A $ should have been detected by ParsedAggregationProjection before we get here.
invariant(fieldName[0] != '$');
// Track whether the projection spec specifies a desired behavior for the _id field.
idSpecified = idSpecified || fieldName == "_id"_sd || fieldName.startsWith("_id."_sd);
switch (elem.type()) {
case BSONType::Bool:
case BSONType::NumberInt:
case BSONType::NumberLong:
case BSONType::NumberDouble:
case BSONType::NumberDecimal: {
// We have already verified this is an exclusion projection. _id is the only field
// which is permitted to be explicitly included here.
invariant(!elem.trueValue() || elem.fieldNameStringData() == "_id"_sd);
if (!elem.trueValue()) {
node->addProjectionForPath(FieldPath(fieldName));
}
break;
}
case BSONType::Object: {
// This object represents a nested projection specification, like the sub-object in
// {a: {b: 0, c: 0}} or {"a.b": {c: 0}}.
ExclusionNode* child;
if (elem.fieldNameStringData().find('.') == std::string::npos) {
child = node->addOrGetChild(fieldName.toString());
} else {
// A dotted field is not allowed in a sub-object, and should have been detected
// in ParsedAggregationProjection's parsing before we get here.
invariant(depth == 0);
// We need to keep adding children to our tree until we create a child that
// represents this dotted path.
child = node;
auto fullPath = FieldPath(fieldName);
while (fullPath.getPathLength() > 1) {
child = child->addOrGetChild(fullPath.getFieldName(0).toString());
fullPath = fullPath.tail();
}
// It is illegal to construct an empty FieldPath, so the above loop ends one
// iteration too soon. Add the last path here.
child = child->addOrGetChild(fullPath.fullPath());
}
parse(elem.Obj(), child, depth + 1);
break;
}
default: { MONGO_UNREACHABLE; }
}
}
// If _id was not specified, then doing nothing will cause it to be included. If the default _id
// policy is kExcludeId, we add a new entry for _id to the ExclusionNode tree here.
if (!idSpecified && _policies.idPolicy == ProjectionPolicies::DefaultIdPolicy::kExcludeId) {
_root->addProjectionForPath({FieldPath("_id")});
}
}
} // namespace parsed_aggregation_projection
} // namespace mongo
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