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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_replace_root.h"
#include <boost/smart_ptr/intrusive_ptr.hpp>
#include "mongo/db/exec/document_value/value.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/pipeline/document_source_replace_root_gen.h"
#include "mongo/db/pipeline/lite_parsed_document_source.h"
namespace mongo {
using boost::intrusive_ptr;
Document ReplaceRootTransformation::applyTransformation(const Document& input) {
// Extract subdocument in the form of a Value.
Value newRoot = _newRoot->evaluate(input, &_expCtx->variables);
// To ensure an accurate user-facing message, any user-facing syntax that uses this stage
// internally must provide an message opener that complies with its documentation.
StringData msgOpener = [&]() {
switch (_specifiedName) {
case UserSpecifiedName::kReplaceRoot:
return "'newRoot' expression "_sd;
case UserSpecifiedName::kReplaceWith:
return "'replacement document' "_sd;
default:
MONGO_UNREACHABLE;
}
}();
// The newRoot expression, if it exists, must evaluate to an object.
uassert(40228,
str::stream() << msgOpener.toString()
<< "must evaluate to an object, but resulting value was: "
<< newRoot.toString() << ". Type of resulting value: '"
<< typeName(newRoot.getType())
<< "'. Input document: " << input.toString(),
newRoot.getType() == BSONType::Object);
// Turn the value into a document.
MutableDocument newDoc(newRoot.getDocument());
newDoc.copyMetaDataFrom(input);
return newDoc.freeze();
}
REGISTER_DOCUMENT_SOURCE(replaceRoot,
LiteParsedDocumentSourceDefault::parse,
DocumentSourceReplaceRoot::createFromBson);
REGISTER_DOCUMENT_SOURCE(replaceWith,
LiteParsedDocumentSourceDefault::parse,
DocumentSourceReplaceRoot::createFromBson);
intrusive_ptr<DocumentSource> DocumentSourceReplaceRoot::createFromBson(
BSONElement elem, const intrusive_ptr<ExpressionContext>& expCtx) {
const auto stageName = elem.fieldNameStringData();
auto newRootExpression = [&]() {
if (stageName == kAliasNameReplaceWith) {
return Expression::parseOperand(expCtx, elem, expCtx->variablesParseState);
}
invariant(
stageName == kStageName,
str::stream() << "Unexpected stage registered with DocumentSourceReplaceRoot parser: "
<< stageName);
uassert(40229,
str::stream() << "expected an object as specification for " << kStageName
<< " stage, got " << typeName(elem.type()),
elem.type() == Object);
auto spec =
ReplaceRootSpec::parse(IDLParserErrorContext(kStageName), elem.embeddedObject());
// The IDL doesn't give us back the type we need to feed into the expression parser, and
// the expression parser needs the extra state in 'vps' and 'expCtx', so for now we have
// to adapt the two.
BSONObj parsingBson = BSON("newRoot" << spec.getNewRoot());
return Expression::parseOperand(
expCtx, parsingBson.firstElement(), expCtx->variablesParseState);
}();
// Whether this was specified as $replaceWith or $replaceRoot, always use the name $replaceRoot
// to simplify the serialization process.
const bool isIndependentOfAnyCollection = false;
return new DocumentSourceSingleDocumentTransformation(
expCtx,
std::make_unique<ReplaceRootTransformation>(
expCtx,
newRootExpression,
(stageName == kStageName) ? ReplaceRootTransformation::UserSpecifiedName::kReplaceRoot
: ReplaceRootTransformation::UserSpecifiedName::kReplaceWith),
kStageName.rawData(),
isIndependentOfAnyCollection);
}
} // namespace mongo
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