Struct Capabilities 

pub struct Capabilities { /* private fields */ }

What a draft can express, queryable before a run.

Implementations

impl Capabilities

pub fn for_draft(draft: DraftVersion) -> Self

The capability table for a draft.

pub fn supports(&self, site: Site, kind: ActionKind) -> Support

Whether kind is available at site, with no per-unit facts.

At Site::Object this is the subgroup-stream column; Self::supports_on answers for a named stream kind.

pub fn supports_on( &self, site: Site, kind: ActionKind, stream_kind: DataStreamType, ) -> Support

Whether kind is available at site for a given stream kind.

pub fn supports_matcher(&self, kind: MatchKind, field: MatcherKey) -> bool

Whether a shaping rule keyed on field can ever claim a unit arriving as kind. supports_matcher, bound to this draft.

pub fn admit_class( &self, class: &ClassRule, ) -> Result<(), UnsupportedMatcherKey>

Admit one class rule, or refuse it naming the draft and the key.

The first key the rule names that supports_matcher answers false for is the refusal, in the order the keys are declared on Matcher — the same first-match convention ShapeProfile::try_new uses for ShapeError::InertMatcher, so a rule with two dead keys reports the one an author reading their own configuration top to bottom reaches first.

A rule that names no stream kind is judged against both

Matcher::stream_kind is optional, and a rule that omits it claims units of any kind. Such a rule is refused only when its key is carried by none of them, because refusing it for being dead on fetch alone would reject a rule that shapes subgroup traffic perfectly well — and a false rejection here is worse than the silence this exists to end, since it rejects a configuration that works.

pub fn admit_profile( &self, profile: &ShapeProfile, ) -> Result<(), UnsupportedMatcherKey>

Admit every class in a profile, or refuse at the first dead key.

The pre-run check ShapeProfile::try_new cannot make: that constructor validates the configuration alone and has no draft, so a rule keyed on something the negotiated draft does not carry is valid to it. This is the same question asked once a draft is known.

A session asks it twice, and the second time is not redundant

Once before it dials, against the draft it is about to frame with, which is the only moment a profile can be refused with nothing yet forwarded. And once more when the peers name a draft, which drafts 07 to 14 do in their SETUP rather than in the ALPN they share — so for that cohort the first answer was given about a configured guess and the second is given about the session actually running. The two differ only where a draft this build did not compile is involved, and that is exactly the case where every rule in the profile is dead.

Trait Implementations

impl Clone for Capabilities

fn clone(&self) -> Capabilities

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Capabilities

impl Debug for Capabilities

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

Formats the value using the given formatter.