clock

Vector clocks for presence replication, ported from Phoenix.Tracker.Clock.

A clock maps each replica to the highest clock value seen from it. A clockset is a list of #(replica, clock) pairs that no member dominates: the set of peers whose state this replica has not yet caught up with.

Types

Clock

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pub type Clock(r) =
  dict.Dict(r, Int)

Values

append_clock

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pub fn append_clock(
  clockset: List(#(n, dict.Dict(r, Int))),
  entry: #(n, dict.Dict(r, Int)),
) -> List(#(n, dict.Dict(r, Int)))

Add a replica’s clock to a clockset, keeping only clocks no other member dominates. Phoenix: append_clock/2.

clockset_replicas

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pub fn clockset_replicas(
  clockset: List(#(n, dict.Dict(r, Int))),
) -> set.Set(n)

The replicas named in a clockset.

dominates

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pub fn dominates(
  c1: dict.Dict(r, Int),
  c2: dict.Dict(r, Int),
) -> Bool

Whether c1 names every replica of c2 with at least its value. Phoenix: dominates?/2.

dominates_or_equal

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pub fn dominates_or_equal(
  c1: dict.Dict(r, Int),
  c2: dict.Dict(r, Int),
) -> Bool

Whether every entry of c1 is at least the matching entry of c2. An empty c1 only dominates-or-equals another empty clock. Phoenix: dominates_or_equal?/2.

filter_replicas

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pub fn filter_replicas(
  clock: dict.Dict(r, Int),
  replicas: List(r),
) -> dict.Dict(r, Int)

The clock restricted to replicas.

lowerbound

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pub fn lowerbound(
  c1: dict.Dict(r, Int),
  c2: dict.Dict(r, Int),
) -> dict.Dict(r, Int)

The entrywise minimum of two clocks.

replicas

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pub fn replicas(clock: dict.Dict(r, Int)) -> List(r)

The replicas a clock mentions.

upperbound

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pub fn upperbound(
  c1: dict.Dict(r, Int),
  c2: dict.Dict(r, Int),
) -> dict.Dict(r, Int)

The entrywise maximum of two clocks.