diff options
Diffstat (limited to 'src/mongo/db/pipeline/expression.cpp')
| -rw-r--r-- | src/mongo/db/pipeline/expression.cpp | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/src/mongo/db/pipeline/expression.cpp b/src/mongo/db/pipeline/expression.cpp index 62b2d1e5018..9d21614c1ed 100644 --- a/src/mongo/db/pipeline/expression.cpp +++ b/src/mongo/db/pipeline/expression.cpp @@ -93,7 +93,7 @@ intrusive_ptr<Expression> Expression::parseObject( BSONObj obj, const VariablesParseState& vps) { if (obj.isEmpty()) { - return ExpressionObject::create(expCtx, {}, {}); + return ExpressionObject::create(expCtx, {}); } if (obj.firstElementFieldName()[0] == '$') { @@ -1882,11 +1882,23 @@ ExpressionObject::ExpressionObject(const boost::intrusive_ptr<ExpressionContext> vector<pair<string, intrusive_ptr<Expression>&>>&& expressions) : Expression(expCtx, std::move(_children)), _expressions(std::move(expressions)) {} -intrusive_ptr<ExpressionObject> ExpressionObject::create( +boost::intrusive_ptr<ExpressionObject> ExpressionObject::create( const boost::intrusive_ptr<ExpressionContext>& expCtx, - std::vector<boost::intrusive_ptr<Expression>> _children, - vector<pair<string, intrusive_ptr<Expression>&>>&& expressions) { - return new ExpressionObject(expCtx, std::move(_children), std::move(expressions)); + std::vector<std::pair<std::string, boost::intrusive_ptr<Expression>>>&& + expressionsWithChildrenInPlace) { + std::vector<boost::intrusive_ptr<Expression>> children; + std::vector<std::pair<std::string, boost::intrusive_ptr<Expression>&>> expressions; + for (auto& [unused, expression] : expressionsWithChildrenInPlace) + // These 'push_back's must complete before we insert references to the 'children' vector + // into the 'expressions' vector since 'push_back' invalidates references. + children.push_back(std::move(expression)); + std::vector<boost::intrusive_ptr<Expression>>::size_type index = 0; + for (auto& [fieldName, unused] : expressionsWithChildrenInPlace) { + expressions.emplace_back(fieldName, children[index]); + ++index; + } + // It is safe to 'std::move' 'children' since the standard guarantees the references are stable. + return new ExpressionObject(expCtx, std::move(children), std::move(expressions)); } intrusive_ptr<ExpressionObject> ExpressionObject::parse( |