A Fundamental Permission Interpretation for Ownership Types

This paper builds a bridge between permissions and ownership types. Ownership is a recognized alias control technique. With ownership, each object is assigned an owner and any access to that object is required to follow some rules based on its owner. Permission is a low-level linear value associated with some piece of state in a program and it is often used to permit certain operations. A permission nesting indicates that some permission is nested in another which intuitively reveals a protection relation between a nested permission and its nester one, with building some restriction among operations furthermore. Permission nesting and ownership behave some common characteristic. In this paper, two ownership models (owners-as-dominators and owners-as-locks) are investigated, and we show they are able to be unified by permission interpretation. Whereafter, we discuss the possibilities of representing multiple ownership by fractional permissions.