Struct HsDirRing

pub(crate) struct HsDirRing {
    params: HsDirParams,
    ring: TiVec<HsDirPos, (HsDirIndex, RouterStatusIdx)>,
}

Available on crate feature hs-common only.

A hash ring as used in NetDir.

This type is immutable once constructed: entries cannot be added, changed, or removed. It can be interpreted only in the context of a given consensus document.

Fields

params: HsDirParams

The parameters (time period and shared random value)

ring: TiVec<HsDirPos, (HsDirIndex, RouterStatusIdx)>

The ring itself.

The first element of each tuple is a 32-byte hash representing a position on the ring; the second is the index for the corresponding relay within self.consensus.relays().

This vector is empty in a partial netdir; it is filled in when we convert to a complete netdir.

Implementations

impl HsDirRing

pub(crate) fn empty_from_params(params: HsDirParams) -> Self

Return a new empty HsDirRing from a given set of parameters.

pub(crate) fn compute( new_params: HsDirParams, this_netdir: &NetDir, prev_netdir: Option<&NetDir>, ) -> Self

Compute the HsDirRing

Reuses existing hash calculations from a previous netdir, if available.

this_netdir.hsdir_rings is not used; the return values from this function will be stored there by PartialNetDir::compute_rings.

pub(crate) fn params(&self) -> &HsDirParams

Return the parameters used for this ring

fn find_pos(&self, hsdir_index: HsDirIndex) -> HsDirPos

Find the location or (notional) insertion point for hsdir_index within ring.

pub(crate) fn ring_items_at( &self, hsdir_index: HsDirIndex, spread: usize, f: impl FnMut(&&(HsDirIndex, RouterStatusIdx)) -> bool, ) -> impl Iterator<Item = &(HsDirIndex, RouterStatusIdx)>

Yield spread items from ring that satisfy the specified filter, starting with hsdir_index.

Wraps around once when we reach the end.

The specified filter function f is applied to each item, and determines whether the item should be yielded or not. This filtering functionality is used by NetDir::hs_dirs to prevent nodes that have already been selected for a lowered-numbered replica to be considered again when choosing spread nodes for a higher-numbered replicas.

Yields no element more than once, even if the ring is smaller than spread.

pub(crate) fn time_period(&self) -> TimePeriod

Return the time period for which this ring applies.

Trait Implementations

impl Clone for HsDirRing

fn clone(&self) -> HsDirRing

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for HsDirRing

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

Formats the value using the given formatter.