nim-dagger/codex/purchasing/purchase.nim

79 lines
2.3 KiB
Nim

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