80 lines
2.4 KiB
Nim
80 lines
2.4 KiB
Nim
import ./statemachine
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import ./states/pending
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import ./states/unknown
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import ./purchaseid
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# Purchase is implemented as a state machine.
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#
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# It can either be a new (pending) purchase that still needs to be submitted
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# on-chain, or it is a purchase that was previously submitted on-chain, and
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# we're just restoring its (unknown) state after a node restart.
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#
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# |
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# v
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# ------------------------- unknown
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# | / /
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# v v /
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# pending ----> submitted ----> started ---------> finished <----/
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# \ \ /
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# \ ------------> failed <----/
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# \ /
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# --> cancelled <-----------------------
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export Purchase
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export purchaseid
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export statemachine
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func new*(
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_: type Purchase,
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requestId: RequestId,
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market: Market,
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clock: Clock
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): Purchase =
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## create a new instance of a Purchase
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##
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var purchase = Purchase.new()
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{.cast(noSideEffect).}:
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purchase.future = newFuture[void]()
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purchase.requestId = requestId
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purchase.market = market
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purchase.clock = clock
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return purchase
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func new*(
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_: type Purchase,
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request: StorageRequest,
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market: Market,
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clock: Clock
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): Purchase =
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## Create a new purchase using the given market and clock
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let purchase = Purchase.new(request.id, market, clock)
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purchase.request = some request
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return purchase
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proc start*(purchase: Purchase) =
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purchase.start(PurchasePending())
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proc load*(purchase: Purchase) =
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purchase.start(PurchaseUnknown())
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proc wait*(purchase: Purchase) {.async.} =
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await purchase.future
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func id*(purchase: Purchase): PurchaseId =
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PurchaseId(purchase.requestId)
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func finished*(purchase: Purchase): bool =
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purchase.future.finished
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func error*(purchase: Purchase): ?(ref CatchableError) =
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if purchase.future.failed:
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some purchase.future.error
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else:
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none (ref CatchableError)
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func state*(purchase: Purchase): ?string =
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proc description(state: State): string =
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$state
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purchase.query(description)
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