nim-codex/codex/contracts/clock.nim

77 lines
2.2 KiB
Nim

import std/times
import pkg/ethers
import pkg/questionable
import pkg/chronos
import pkg/stint
import ../clock
import ../conf
export clock
logScope:
topics = "contracts clock"
type
OnChainClock* = ref object of Clock
provider: Provider
subscription: Subscription
offset: times.Duration
blockNumber: UInt256
started: bool
newBlock: AsyncEvent
proc new*(_: type OnChainClock, provider: Provider): OnChainClock =
OnChainClock(provider: provider, newBlock: newAsyncEvent())
proc update(clock: OnChainClock, blck: Block) =
if number =? blck.number and number > clock.blockNumber:
let blockTime = initTime(blck.timestamp.truncate(int64), 0)
let computerTime = getTime()
clock.offset = blockTime - computerTime
clock.blockNumber = number
trace "updated clock", blockTime=blck.timestamp, blockNumber=number, offset=clock.offset
clock.newBlock.fire()
proc update(clock: OnChainClock) {.async.} =
try:
if latest =? (await clock.provider.getBlock(BlockTag.latest)):
clock.update(latest)
except CancelledError as error:
raise error
except CatchableError as error:
debug "error updating clock: ", error=error.msg
discard
method start*(clock: OnChainClock) {.async.} =
if clock.started:
return
proc onBlock(blckResult: ?!Block) =
if eventError =? blckResult.errorOption:
error "There was an error in block subscription", msg=eventError.msg
return
# ignore block parameter; hardhat may call this with pending blocks
asyncSpawn clock.update()
await clock.update()
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 =
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))