Trait tor_circmgr::isolation::Isolation

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pub trait Isolation: Sealed + Downcast + DynClone + Debug + Send + Sync + 'static {
    fn compatible(&self, other: &dyn Isolation) -> bool;
    fn join(&self, other: &dyn Isolation) -> Option<Box<dyn Isolation>>;
}

Expand description

A type that can make isolation decisions about streams it is attached to.

Types that implement Isolation contain properties about a stream that are used to make decisions about whether that stream can share the same circuit as other streams. You may pass in any type implementing Isolation when creating a stream via TorClient::connect_with_prefs, or constructing a circuit with CircMgr::get_or_launch_exit().

You typically do not want to implement this trait directly. Instead, most users should implement IsolationHelper.

Required Methods

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fn compatible(&self, other: &dyn Isolation) -> bool

Return true if this Isolation is compatible with another.

Two streams may share a circuit if and only if they have compatible Isolations.

Requirements

For correctness, this relation must be symmetrical and reflexive: self.compatible(other) must equal other.compatible(self), and self.compatible(self) must be true.

For correctness, this function must always give the same result as self.join(other).is_some().

This relationship does not have to be transitive: it’s possible that stream A can share a circuit with either stream B or stream C, but not with both.

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fn join(&self, other: &dyn Isolation) -> Option<Box<dyn Isolation>>

Join two Isolation into the intersection of what each allows.

A circuit’s isolation is the join of the isolation values of all of the streams that have ever used that circuit. A circuit’s isolation can never be None: streams that would cause it to be None can’t be attached to the circuit.

When a stream is added to a circuit, join is used to calculate the circuit’s new isolation.

Requirements

For correctness, this function must be commutative: self.join(other) must equal other.join(self). Also, it must be idempotent: self.join(self) must equal self.