nim-codex/codex/contracts/clock.nim

72 lines
2.2 KiB
Nim

import std/times
import pkg/ethers
import pkg/chronos
import pkg/stint
import pkg/upraises
import ../clock
import ../conf
export clock
logScope:
topics = "contracts clock"
type
OnChainClock* = ref object of Clock
provider: Provider
subscription: Subscription
offset: times.Duration
started: bool
newBlock: AsyncEvent
lastBlockTime: UInt256
proc new*(_: type OnChainClock, provider: Provider): OnChainClock =
OnChainClock(provider: provider, newBlock: newAsyncEvent())
method start*(clock: OnChainClock) {.async.} =
if clock.started:
return
proc onBlock(blck: Block) =
let blockTime = initTime(blck.timestamp.truncate(int64), 0)
let computerTime = getTime()
clock.offset = blockTime - computerTime
clock.lastBlockTime = blck.timestamp
clock.newBlock.fire()
if latestBlock =? (await clock.provider.getBlock(BlockTag.latest)):
onBlock(latestBlock)
clock.subscription = await clock.provider.subscribe(onBlock)
clock.started = true
method stop*(clock: OnChainClock) {.async.} =
if not clock.started:
return
await clock.subscription.unsubscribe()
clock.started = false
method now*(clock: OnChainClock): SecondsSince1970 {.raises: [].}=
when codex_use_hardhat:
# hardhat's latest block.timestamp is usually 1s behind the block timestamp
# in the newHeads event. When testing, always return the latest block.
try:
if queriedBlock =? (waitFor clock.provider.getBlock(BlockTag.latest)):
trace "using last block timestamp for clock.now",
lastBlockTimestamp = queriedBlock.timestamp.truncate(int64),
cachedBlockTimestamp = clock.lastBlockTime.truncate(int64)
return queriedBlock.timestamp.truncate(int64)
except CatchableError as e:
warn "failed to get latest block timestamp", error = e.msg
return clock.lastBlockTime.truncate(int64)
else:
doAssert clock.started, "clock should be started before calling now()"
return toUnix(getTime() + clock.offset)
method waitUntil*(clock: OnChainClock, time: SecondsSince1970) {.async.} =
while (let difference = time - clock.now(); difference > 0):
clock.newBlock.clear()
discard await clock.newBlock.wait().withTimeout(chronos.seconds(difference))