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/**
* 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 <http://www.gnu.org/licenses/>.
*
* 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.
*/
#include "mongo/platform/basic.h"
#include "mongo/db/pipeline/document_source_lookup_change_post_image.h"
#include "mongo/bson/simple_bsonelement_comparator.h"
namespace mongo {
constexpr StringData DocumentSourceLookupChangePostImage::kStageName;
constexpr StringData DocumentSourceLookupChangePostImage::kFullDocumentFieldName;
namespace {
Value assertFieldHasType(const Document& fullDoc, StringData fieldName, BSONType expectedType) {
auto val = fullDoc[fieldName];
uassert(40578,
str::stream() << "failed to look up post image after change: expected \"" << fieldName
<< "\" field to have type "
<< typeName(expectedType)
<< ", instead found type "
<< typeName(val.getType())
<< ": "
<< val.toString()
<< ", full object: "
<< fullDoc.toString(),
val.getType() == expectedType);
return val;
}
} // namespace
DocumentSource::GetNextResult DocumentSourceLookupChangePostImage::getNext() {
pExpCtx->checkForInterrupt();
auto input = pSource->getNext();
if (!input.isAdvanced()) {
return input;
}
auto opTypeVal = assertFieldHasType(
input.getDocument(), DocumentSourceChangeStream::kOperationTypeField, BSONType::String);
if (opTypeVal.getString() != DocumentSourceChangeStream::kUpdateOpType) {
return input;
}
MutableDocument output(input.releaseDocument());
output[kFullDocumentFieldName] = lookupPostImage(output.peek());
return output.freeze();
}
NamespaceString DocumentSourceLookupChangePostImage::assertNamespaceMatches(
const Document& inputDoc) const {
auto namespaceObject =
assertFieldHasType(inputDoc, DocumentSourceChangeStream::kNamespaceField, BSONType::Object)
.getDocument();
auto dbName = assertFieldHasType(namespaceObject, "db"_sd, BSONType::String);
auto collectionName = assertFieldHasType(namespaceObject, "coll"_sd, BSONType::String);
NamespaceString nss(dbName.getString(), collectionName.getString());
uassert(40579,
str::stream() << "unexpected namespace during post image lookup: " << nss.ns()
<< ", expected "
<< pExpCtx->ns.ns(),
nss == pExpCtx->ns);
return nss;
}
Value DocumentSourceLookupChangePostImage::lookupPostImage(const Document& updateOp) const {
// Make sure we have a well-formed input.
auto nss = assertNamespaceMatches(updateOp);
auto documentKey = assertFieldHasType(
updateOp, DocumentSourceChangeStream::kDocumentKeyField, BSONType::Object);
auto matchSpec = BSON("$match" << documentKey);
// Extract the UUID from resume token and do change stream lookups by UUID.
auto resumeToken =
ResumeToken::parse(updateOp[DocumentSourceChangeStream::kIdField].getDocument());
// TODO SERVER-29134 we need to extract the namespace from the document and set them on the new
// ExpressionContext if we're getting notifications from an entire database.
auto foreignExpCtx = pExpCtx->copyWith(nss, resumeToken.getData().uuid);
auto pipelineStatus = _mongoProcessInterface->makePipeline({matchSpec}, foreignExpCtx);
if (pipelineStatus.getStatus() == ErrorCodes::NamespaceNotFound) {
// We couldn't find the collection with UUID, it may have been dropped.
return Value(BSONNULL);
}
auto pipeline = uassertStatusOK(std::move(pipelineStatus));
if (auto first = pipeline->getNext()) {
auto lookedUpDocument = Value(*first);
if (auto next = pipeline->getNext()) {
uasserted(40580,
str::stream() << "found more than document with documentKey "
<< documentKey.toString()
<< " while looking up post image after change: ["
<< lookedUpDocument.toString()
<< ", "
<< next->toString()
<< "]");
}
return lookedUpDocument;
}
// We couldn't find it with the documentKey, it may have been deleted.
return Value(BSONNULL);
}
} // namespace mongo
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