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/**
* Copyright (C) 2019-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/update/pipeline_executor.h"
#include "mongo/bson/mutable/document.h"
#include "mongo/db/bson/dotted_path_support.h"
#include "mongo/db/pipeline/document_source_queue.h"
#include "mongo/db/pipeline/lite_parsed_pipeline.h"
#include "mongo/db/pipeline/variable_validation.h"
#include "mongo/db/query/query_feature_flags_gen.h"
#include "mongo/db/update/document_diff_calculator.h"
#include "mongo/db/update/object_replace_executor.h"
#include "mongo/db/update/storage_validation.h"
#include "mongo/db/update/update_oplog_entry_serialization.h"
namespace mongo {
namespace {
constexpr StringData kIdFieldName = "_id"_sd;
} // namespace
PipelineExecutor::PipelineExecutor(const boost::intrusive_ptr<ExpressionContext>& expCtx,
const std::vector<BSONObj>& pipeline,
boost::optional<BSONObj> constants)
: _expCtx(expCtx) {
// "Resolve" involved namespaces into a map. We have to populate this map so that any
// $lookups, etc. will not fail instantiation. They will not be used for execution as these
// stages are not allowed within an update context.
LiteParsedPipeline liteParsedPipeline(NamespaceString("dummy.namespace"), pipeline);
StringMap<ExpressionContext::ResolvedNamespace> resolvedNamespaces;
for (auto&& nss : liteParsedPipeline.getInvolvedNamespaces()) {
resolvedNamespaces.try_emplace(nss.coll(), nss, std::vector<BSONObj>{});
}
if (constants) {
for (auto&& constElem : *constants) {
const auto constName = constElem.fieldNameStringData();
variableValidation::validateNameForUserRead(constName);
auto varId = _expCtx->variablesParseState.defineVariable(constName);
_expCtx->variables.setConstantValue(varId, Value(constElem));
}
}
_expCtx->setResolvedNamespaces(resolvedNamespaces);
_expCtx->startExpressionCounters();
_pipeline = Pipeline::parse(pipeline, _expCtx);
_expCtx->stopExpressionCounters();
// Validate the update pipeline.
for (auto&& stage : _pipeline->getSources()) {
auto stageConstraints = stage->constraints();
uassert(ErrorCodes::InvalidOptions,
str::stream() << stage->getSourceName()
<< " is not allowed to be used within an update",
stageConstraints.isAllowedWithinUpdatePipeline);
invariant(stageConstraints.requiredPosition ==
StageConstraints::PositionRequirement::kNone);
invariant(!stageConstraints.isIndependentOfAnyCollection);
}
_pipeline->addInitialSource(DocumentSourceQueue::create(expCtx));
}
UpdateExecutor::ApplyResult PipelineExecutor::applyUpdate(ApplyParams applyParams) const {
const auto originalDoc = applyParams.element.getDocument().getObject();
DocumentSourceQueue* queueStage = static_cast<DocumentSourceQueue*>(_pipeline->peekFront());
queueStage->emplace_back(Document{originalDoc});
const auto transformedDoc = _pipeline->getNext()->toBson();
const auto transformedDocHasIdField = transformedDoc.hasField(kIdFieldName);
// Replace the pre-image document in applyParams with the post image we got from running the
// post image.
auto ret = ObjectReplaceExecutor::applyReplacementUpdate(
applyParams,
transformedDoc,
transformedDocHasIdField,
feature_flags::gFeatureFlagDotsAndDollars.isEnabledAndIgnoreFCV());
// The oplog entry should not have been populated yet.
invariant(ret.oplogEntry.isEmpty());
if (applyParams.logMode != ApplyParams::LogMode::kDoNotGenerateOplogEntry && !ret.noop) {
if (applyParams.logMode == ApplyParams::LogMode::kGenerateOplogEntry) {
// We're allowed to generate $v: 2 log entries. The $v:2 has certain meta-fields like
// '$v', 'diff'. So we pad some additional byte while computing diff.
const auto diffOutput =
doc_diff::computeDiff(originalDoc,
transformedDoc,
update_oplog_entry::kSizeOfDeltaOplogEntryMetadata,
applyParams.indexData);
if (diffOutput) {
ret.oplogEntry = update_oplog_entry::makeDeltaOplogEntry(diffOutput->diff);
ret.indexesAffected = diffOutput->indexesAffected;
return ret;
}
}
// Either we can't use diffing or diffing failed so fall back to full replacement. Set the
// replacement to the value set by the object replace executor, in case it changed _id or
// anything like that.
ret.oplogEntry = update_oplog_entry::makeReplacementOplogEntry(
applyParams.element.getDocument().getObject());
}
return ret;
}
Value PipelineExecutor::serialize() const {
std::vector<Value> valueArray;
for (const auto& stage : _pipeline->getSources()) {
// The queue stage we add to adapt the pull-based '_pipeline' to our use case should not
// be serialized out. Firstly, this was not part of the user's pipeline and is just an
// implementation detail. It wouldn't have much value in exposing. Secondly, supporting
// a serialization that we can later re-parse is non trivial. See the comment in
// DocumentSourceQueue for more details.
if (typeid(*stage) == typeid(DocumentSourceQueue)) {
continue;
}
stage->serializeToArray(valueArray);
}
return Value(valueArray);
}
} // namespace mongo
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