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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/document_source_project.h"
#include <boost/optional.hpp>
#include <boost/smart_ptr/intrusive_ptr.hpp>
#include "mongo/db/exec/projection_executor.h"
#include "mongo/db/exec/projection_executor_builder.h"
#include "mongo/db/pipeline/lite_parsed_document_source.h"
#include "mongo/db/query/projection_parser.h"
namespace mongo {
using boost::intrusive_ptr;
REGISTER_DOCUMENT_SOURCE(project,
LiteParsedDocumentSourceDefault::parse,
DocumentSourceProject::createFromBson);
REGISTER_DOCUMENT_SOURCE(unset,
LiteParsedDocumentSourceDefault::parse,
DocumentSourceProject::createFromBson);
namespace {
BSONObj buildExclusionProjectionSpecification(const std::vector<BSONElement>& unsetSpec) {
BSONObjBuilder objBuilder;
for (const auto& elem : unsetSpec) {
objBuilder << elem.valueStringData() << 0;
}
return objBuilder.obj();
}
} // namespace
intrusive_ptr<DocumentSource> DocumentSourceProject::create(
BSONObj projectSpec, const intrusive_ptr<ExpressionContext>& expCtx, StringData specifiedName) {
const bool isIndependentOfAnyCollection = false;
intrusive_ptr<DocumentSource> project(new DocumentSourceSingleDocumentTransformation(
expCtx,
[&]() {
// The ProjectionExecutor will internally perform a check to see if the provided
// specification is valid, and throw an exception if it was not. The exception is caught
// here so we can add the name that was actually specified by the user, be it $project
// or an alias.
try {
auto policies = ProjectionPolicies::aggregateProjectionPolicies();
auto projection = projection_ast::parse(expCtx, projectSpec, policies);
// We won't optimize the executor on creation, and will do it as part of the
// pipeline optimization process when requested via the 'optimize()' method on
// 'DocumentSourceSingleDocumentTransformation', so we won't pass the
// 'kOptimzeExecutor' flag to the projection executor builder.
//
// Note that this is also important for $lookup inner pipelines to not being
// optimized too early, as it may lead to incorrect positioning of the caching
// stage due to missing dependencies on certain variables, as they could have been
// optimized away.
auto builderParams = projection_executor::BuilderParamsBitSet{
projection_executor::kDefaultBuilderParams};
builderParams.reset(projection_executor::kOptimizeExecutor);
return projection_executor::buildProjectionExecutor(
expCtx, &projection, policies, builderParams);
} catch (DBException& ex) {
ex.addContext("Invalid " + specifiedName.toString());
throw;
}
}(),
kStageName,
isIndependentOfAnyCollection));
return project;
}
intrusive_ptr<DocumentSource> DocumentSourceProject::createFromBson(
BSONElement elem, const intrusive_ptr<ExpressionContext>& expCtx) {
if (elem.fieldNameStringData() == kStageName) {
uassert(15969, "$project specification must be an object", elem.type() == BSONType::Object);
return DocumentSourceProject::create(elem.Obj(), expCtx, elem.fieldNameStringData());
}
invariant(elem.fieldNameStringData() == kAliasNameUnset);
uassert(31002,
"$unset specification must be a string or an array",
(elem.type() == BSONType::Array || elem.type() == BSONType::String));
const auto unsetSpec =
elem.type() == BSONType::Array ? elem.Array() : std::vector<mongo::BSONElement>{1, elem};
uassert(31119,
"$unset specification must be a string or an array with at least one field",
unsetSpec.size() > 0);
uassert(31120,
"$unset specification must be a string or an array containing only string values",
std::all_of(unsetSpec.cbegin(), unsetSpec.cend(), [](BSONElement elem) {
return elem.type() == BSONType::String;
}));
return DocumentSourceProject::create(
buildExclusionProjectionSpecification(unsetSpec), expCtx, elem.fieldNameStringData());
}
} // namespace mongo
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