44 lines
1.1 KiB
Nim
44 lines
1.1 KiB
Nim
import std/times
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import pkg/ethers
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import pkg/chronos
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import pkg/stint
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import ../clock
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export clock
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type
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OnChainClock* = ref object of Clock
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provider: Provider
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subscription: Subscription
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offset: times.Duration
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started: bool
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proc new*(_: type OnChainClock, provider: Provider): OnChainClock =
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OnChainClock(provider: provider)
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proc start*(clock: OnChainClock) {.async.} =
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if clock.started:
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return
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clock.started = true
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proc onBlock(blck: Block) {.async, upraises:[].} =
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let blockTime = initTime(blck.timestamp.truncate(int64), 0)
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let computerTime = getTime()
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clock.offset = blockTime - computerTime
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if latestBlock =? (await clock.provider.getBlock(BlockTag.latest)):
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await onBlock(latestBlock)
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clock.subscription = await clock.provider.subscribe(onBlock)
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proc stop*(clock: OnChainClock) {.async.} =
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if not clock.started:
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return
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clock.started = false
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await clock.subscription.unsubscribe()
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method now*(clock: OnChainClock): SecondsSince1970 =
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doAssert clock.started, "clock should be started before calling now()"
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toUnix(getTime() + clock.offset)
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