diff options
Diffstat (limited to 'src/mongo/db/pipeline/document_source_project.cpp')
| -rw-r--r-- | src/mongo/db/pipeline/document_source_project.cpp | 168 |
1 files changed, 81 insertions, 87 deletions
diff --git a/src/mongo/db/pipeline/document_source_project.cpp b/src/mongo/db/pipeline/document_source_project.cpp index c652b177fa4..c0bc9aa68a2 100644 --- a/src/mongo/db/pipeline/document_source_project.cpp +++ b/src/mongo/db/pipeline/document_source_project.cpp @@ -38,91 +38,85 @@ namespace mongo { - using boost::intrusive_ptr; - using std::string; - using std::vector; - - const char DocumentSourceProject::projectName[] = "$project"; - - DocumentSourceProject::DocumentSourceProject(const intrusive_ptr<ExpressionContext>& pExpCtx, - const intrusive_ptr<ExpressionObject>& exprObj) - : DocumentSource(pExpCtx) - , pEO(exprObj) - { } - - const char *DocumentSourceProject::getSourceName() const { - return projectName; - } - - boost::optional<Document> DocumentSourceProject::getNext() { - pExpCtx->checkForInterrupt(); - - boost::optional<Document> input = pSource->getNext(); - if (!input) - return boost::none; - - /* create the result document */ - const size_t sizeHint = pEO->getSizeHint(); - MutableDocument out (sizeHint); - out.copyMetaDataFrom(*input); - - /* - Use the ExpressionObject to create the base result. - - If we're excluding fields at the top level, leave out the _id if - it is found, because we took care of it above. - */ - _variables->setRoot(*input); - pEO->addToDocument(out, *input, _variables.get()); - _variables->clearRoot(); - - return out.freeze(); - } - - intrusive_ptr<DocumentSource> DocumentSourceProject::optimize() { - intrusive_ptr<Expression> pE(pEO->optimize()); - pEO = boost::dynamic_pointer_cast<ExpressionObject>(pE); - return this; - } - - Value DocumentSourceProject::serialize(bool explain) const { - return Value(DOC(getSourceName() << pEO->serialize(explain))); - } - - intrusive_ptr<DocumentSource> DocumentSourceProject::createFromBson( - BSONElement elem, - const intrusive_ptr<ExpressionContext> &pExpCtx) { - - /* validate */ - uassert(15969, str::stream() << projectName << - " specification must be an object", - elem.type() == Object); - - Expression::ObjectCtx objectCtx( - Expression::ObjectCtx::DOCUMENT_OK - | Expression::ObjectCtx::TOP_LEVEL - | Expression::ObjectCtx::INCLUSION_OK - ); - - VariablesIdGenerator idGenerator; - VariablesParseState vps(&idGenerator); - intrusive_ptr<Expression> parsed = Expression::parseObject(elem.Obj(), &objectCtx, vps); - ExpressionObject* exprObj = dynamic_cast<ExpressionObject*>(parsed.get()); - massert(16402, "parseObject() returned wrong type of Expression", exprObj); - uassert(16403, "$projection requires at least one output field", exprObj->getFieldCount()); - - intrusive_ptr<DocumentSourceProject> pProject(new DocumentSourceProject(pExpCtx, exprObj)); - pProject->_variables.reset(new Variables(idGenerator.getIdCount())); - - BSONObj projectObj = elem.Obj(); - pProject->_raw = projectObj.getOwned(); - - return pProject; - } - - DocumentSource::GetDepsReturn DocumentSourceProject::getDependencies(DepsTracker* deps) const { - vector<string> path; // empty == top-level - pEO->addDependencies(deps, &path); - return EXHAUSTIVE_FIELDS; - } +using boost::intrusive_ptr; +using std::string; +using std::vector; + +const char DocumentSourceProject::projectName[] = "$project"; + +DocumentSourceProject::DocumentSourceProject(const intrusive_ptr<ExpressionContext>& pExpCtx, + const intrusive_ptr<ExpressionObject>& exprObj) + : DocumentSource(pExpCtx), pEO(exprObj) {} + +const char* DocumentSourceProject::getSourceName() const { + return projectName; +} + +boost::optional<Document> DocumentSourceProject::getNext() { + pExpCtx->checkForInterrupt(); + + boost::optional<Document> input = pSource->getNext(); + if (!input) + return boost::none; + + /* create the result document */ + const size_t sizeHint = pEO->getSizeHint(); + MutableDocument out(sizeHint); + out.copyMetaDataFrom(*input); + + /* + Use the ExpressionObject to create the base result. + + If we're excluding fields at the top level, leave out the _id if + it is found, because we took care of it above. + */ + _variables->setRoot(*input); + pEO->addToDocument(out, *input, _variables.get()); + _variables->clearRoot(); + + return out.freeze(); +} + +intrusive_ptr<DocumentSource> DocumentSourceProject::optimize() { + intrusive_ptr<Expression> pE(pEO->optimize()); + pEO = boost::dynamic_pointer_cast<ExpressionObject>(pE); + return this; +} + +Value DocumentSourceProject::serialize(bool explain) const { + return Value(DOC(getSourceName() << pEO->serialize(explain))); +} + +intrusive_ptr<DocumentSource> DocumentSourceProject::createFromBson( + BSONElement elem, const intrusive_ptr<ExpressionContext>& pExpCtx) { + /* validate */ + uassert(15969, + str::stream() << projectName << " specification must be an object", + elem.type() == Object); + + Expression::ObjectCtx objectCtx(Expression::ObjectCtx::DOCUMENT_OK | + Expression::ObjectCtx::TOP_LEVEL | + Expression::ObjectCtx::INCLUSION_OK); + + VariablesIdGenerator idGenerator; + VariablesParseState vps(&idGenerator); + intrusive_ptr<Expression> parsed = Expression::parseObject(elem.Obj(), &objectCtx, vps); + ExpressionObject* exprObj = dynamic_cast<ExpressionObject*>(parsed.get()); + massert(16402, "parseObject() returned wrong type of Expression", exprObj); + uassert(16403, "$projection requires at least one output field", exprObj->getFieldCount()); + + intrusive_ptr<DocumentSourceProject> pProject(new DocumentSourceProject(pExpCtx, exprObj)); + pProject->_variables.reset(new Variables(idGenerator.getIdCount())); + + BSONObj projectObj = elem.Obj(); + pProject->_raw = projectObj.getOwned(); + + return pProject; +} + +DocumentSource::GetDepsReturn DocumentSourceProject::getDependencies(DepsTracker* deps) const { + vector<string> path; // empty == top-level + pEO->addDependencies(deps, &path); + return EXHAUSTIVE_FIELDS; +} } |