Struct Capability 

pub struct Capability<P, R>
where
    P: Permission,
    R: Resource,
{ /* private fields */ }

An unforgeable proof that subject subject holds permission P on resource R.

Construct via PolicyEngine::mint_capability. The phantom parameters P and R are erased at runtime but enforced at compile time.

Implementations

impl<P, R> Capability<P, R>

where P: Permission, R: Resource,

pub fn subject(&self) -> &str

The subject that holds this capability.

pub fn resource_id(&self) -> &str

The resource identifier this capability covers.

pub fn permission_name() -> &'static str

The permission name (from the type parameter).

impl<P, R> Capability<P, R>

where P: Permission, R: Resource,

pub fn coerce<Q>(self) -> Capability<Q, R>

where Q: Permission, P: Implies<Q>,

Downcast this capability to a less-privileged one.

Only callable when P: Implies<Q> — the compiler enforces the lattice. This is a zero-cost operation: subject and resource are preserved; only the permission type parameter changes.

Example

let write_cap: Capability<CanWrite, Report> =
    agent.request_capability(&report).await?;
// CanWrite → CanRead is a valid lattice relationship:
let read_cap: Capability<CanRead, Report> = write_cap.coerce();

Trait Implementations

impl<P, R> Debug for Capability<P, R>

where P: Permission, R: Resource,

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<P, R> Display for Capability<P, R>

where P: Permission, R: Resource,

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.