133 lines
4.8 KiB
Nim
133 lines
4.8 KiB
Nim
# beacon_chain
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# Copyright (c) 2018-2024 Status Research & Development GmbH
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# Licensed and distributed under either of
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# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
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# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
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# at your option. This file may not be copied, modified, or distributed except according to those terms.
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{.push raises: [].}
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import
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std/math,
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results,
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chronos/timer, chronicles,
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./spec/beacon_time
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from std/times import Time, getTime, fromUnix, toUnix, `<`, `-`, inNanoseconds
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export timer.Duration, Moment, now, beacon_time
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type
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BeaconClock* = object
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## The beacon clock represents time as it passes on a beacon chain. Beacon
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## time is locked to unix time, starting at a particular offset set during
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## beacon chain instantiation.
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##
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## Time on the beacon chain determines what actions should be taken and
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## which blocks are valid - in particular, blocks are not valid if they
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## come from the future as seen from the local clock.
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##
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## https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.2/specs/phase0/fork-choice.md#fork-choice
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##
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# TODO consider NTP and network-adjusted timestamps as outlined here:
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# https://ethresear.ch/t/network-adjusted-timestamps/4187
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genesis: Time
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GetBeaconTimeFn* = proc(): BeaconTime {.gcsafe, raises: [].}
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proc init*(T: type BeaconClock, genesis_time: uint64): Opt[T] =
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# Since we'll be converting beacon time differences to nanoseconds,
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# the time can't be outrageously far from now
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if genesis_time > (getTime().toUnix().uint64 + 100'u64 * 365'u64 * 24'u64 *
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60'u64 * 60'u64) or
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genesis_time < GENESIS_SLOT * SECONDS_PER_SLOT:
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Opt.none(BeaconClock)
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else:
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let
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unixGenesis = fromUnix(genesis_time.int64)
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# GENESIS_SLOT offsets slot time, but to simplify calculations, we apply that
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# offset to genesis instead of applying it at every time conversion
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unixGenesisOffset = times.seconds(int(GENESIS_SLOT * SECONDS_PER_SLOT))
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Opt.some T(genesis: unixGenesis - unixGenesisOffset)
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func toBeaconTime*(c: BeaconClock, t: Time): BeaconTime =
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BeaconTime(ns_since_genesis: inNanoseconds(t - c.genesis))
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func toSlot*(c: BeaconClock, t: Time): tuple[afterGenesis: bool, slot: Slot] =
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c.toBeaconTime(t).toSlot()
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proc now*(c: BeaconClock): BeaconTime =
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## Current time, in slots - this may end up being less than GENESIS_SLOT(!)
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toBeaconTime(c, getTime())
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func getBeaconTimeFn*(c: BeaconClock): GetBeaconTimeFn =
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return proc(): BeaconTime = c.now()
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proc fromNow*(c: BeaconClock, t: BeaconTime): tuple[inFuture: bool, offset: Duration] =
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let now = c.now()
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if t > now:
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(true, nanoseconds((t - now).nanoseconds))
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else:
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(false, nanoseconds((now - t).nanoseconds))
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proc fromNow*(c: BeaconClock, slot: Slot): tuple[inFuture: bool, offset: Duration] =
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c.fromNow(slot.start_beacon_time())
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proc durationToNextSlot*(c: BeaconClock): Duration =
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let
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currentTime = c.now()
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currentSlot = currentTime.toSlot()
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if currentSlot.afterGenesis:
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let nextSlot = currentSlot.slot + 1
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nanoseconds(
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(nextSlot.start_beacon_time() - currentTime).nanoseconds)
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else:
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# absoluteTime = BeaconTime(-currentTime.ns_since_genesis).
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let
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absoluteTime = Slot(0).start_beacon_time() +
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(Slot(0).start_beacon_time() - currentTime)
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timeToNextSlot = absoluteTime - currentSlot.slot.start_beacon_time()
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nanoseconds(timeToNextSlot.nanoseconds)
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proc durationToNextEpoch*(c: BeaconClock): Duration =
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let
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currentTime = c.now()
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currentSlot = currentTime.toSlot()
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if currentSlot.afterGenesis:
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let nextEpochSlot = (currentSlot.slot.epoch() + 1).start_slot()
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nanoseconds(
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(nextEpochSlot.start_beacon_time() - currentTime).nanoseconds)
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else:
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# absoluteTime = BeaconTime(-currentTime.ns_since_genesis).
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let
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absoluteTime = Slot(0).start_beacon_time() +
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(Slot(0).start_beacon_time() - currentTime)
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timeToNextEpoch = absoluteTime -
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currentSlot.slot.epoch().start_slot().start_beacon_time()
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nanoseconds(timeToNextEpoch.nanoseconds)
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func saturate*(d: tuple[inFuture: bool, offset: Duration]): Duration =
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if d.inFuture: d.offset else: seconds(0)
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func shortLog*(d: Duration): string =
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$d
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func toFloatSeconds*(d: Duration): float =
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float(milliseconds(d)) / 1000.0
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func fromFloatSeconds*(T: type Duration, f: float): Duration =
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case classify(f)
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of fcNormal:
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if f >= float(int64.high() div 1_000_000_000): InfiniteDuration
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elif f <= 0: ZeroDuration
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else: nanoseconds(int64(f * 1_000_000_000))
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of fcSubnormal, fcZero, fcNegZero, fcNan, fcNegInf: ZeroDuration
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of fcInf: InfiniteDuration
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chronicles.formatIt Duration: $it
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const MinSignificantProcessingDuration* = 250.millis
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