Throughout the server, OperationContexts are operated on via a naked pointer always named opCtx. Often there is a stdx::unique_ptr<OperationContext> (typedef'd "UniqueOperationContext") also named opCtx. There is no way to protect against a null opCtx, or any of myriad implicit, incorrect pointer operations.

• OperationContext should be renamed OperationContext::Impl.
• OperationContext itself should be a struct wrapping a std::unique_ptr<OperationContext::Impl>.
• Uses of OperationContext* in interfaces should be replaced with an OpCtxRef, wrapping a guaranteed non-null OperationContext::Impl*.
• Member functions of the present OperationContext should be moved to OpCtxRef or to Impl, according to usage.