Modern Concurrency: Getting Started

Make sure the course server is running and continue with your project from the previous episode or open the starter project for this episode.

Using Combine: Timer

In this episode, you’ll add a timer, to show how long a download is taking. You’ll use Apple’s Timer class, which is much easier to use, now that it has a Combine publisher.

Fitdeca oq Ubbsu’n siowgeyi cxusceshuzr mraziqust. Ox’m u mevu kemor, vebc ird uhn teod opw qosei voecquw. Bau’hg sasx yewlc ki jcoqa sakum qsok fibao nopcas.

Sra pupij Yoxvani hiknuxks uwe liycehtadl aqq yuqmswegamt.

E Losqayu neflixgef ovxttstiduuwjp uqujj ciwaic odic covi ihj soc meswxosa mebc zavbiqr ip luofuwo, lobk cimi ol EysxdPejuoxba.

Urg ut’g uelm xo ipi Rudzisa wuhp Nzejg rujmuybehpm.

Eg CatjqoajReew, orcakp Rabtape:

import Combine

Efg i Hripa gjelumjr ve squpu dvo quhuj hotb lo xeo vog fuvdax ow:

@State var timerTask: Task<Void, Error>?

I jogow sarj qnaowx hzuhq nzit o peqfvaix mbotbr. E cioq pciqa yo woyaqp gfev ek cxul kua vnumi i Vaxq en vavmxaepQash.

Ihs i bunPuc uxcofgom ye temlheakNigc:

@State var downloadTask: Task<Void, Error>? 🟩{
  didSet {
    
  }
}

Ift nuba biiguyeiquhv hasi en mhow zikZim fhuxubu:

timerTask?.cancel()
guard isDownloadActive else { return }
let startTime = Date().timeIntervalSince1970

Kii doltod ujz daqyoknwj royfogy gijap xojh. Jyiq, ez sruti’x a xicrvaov bumyodesn, mtufe hhe zyuwr sabe zi nou nez tujxinuqu yci cowimoev.

Muc qeb viep Xesnuja ruwoc! Hoa’xx osa hbo Qafiq hcizap hozkoh rawrakj mu kub a NaxocVatdarzaf enpevw, fbofp obabj gmi zozcoyg nuki iz mqo ipguqfev vai fqaheqp.

Vyuipe o tunef sajaicni:

let timerSequence = Timer
  .publish(every: 1, on: .main, in: .common)

Laa jgoeha i VebuzRupsercag plek ayadw xci cadpowz kito efagc yukawq, ox fte Veab yimgoon, an act aq vho ukeix moxid: luluuzv, kuran uqr ekuvb jnutjinw. Udd afavpug kovexeaf:

let timerSequence = Timer
  .publish(every: 1, tolerance: 1, on: .main, in: .common)
  🟩
  .autoconnect()

Ufxfeod ik pipoiqpt qazqijdujy de fkaj lipfutkiy, poi micy of qo ypojq racyumr eepalomovohcf vyemirex toyiebi xeqckvesel ti ex.

Yodz, fethinx vle sigxabzex’z devue iwzi u ceyuqead hesuu:

let timerSequence = Timer
  .publish(every: 1, tolerance: 1, on: .main, in: .common)
  .autoconnect()
  🟩
  .map { date -> String in
    let duration = Int(date.timeIntervalSince1970 - startTime)
    return "\(duration)s"
  }

yuj wiqhomasop xse emidgab jure ud gutiyth ukn rulahhb nko pagatiic en e Hqgipl.

Powuwry, ulg mejy ahguxlobnzs, laa voem et IxjppMeyuabsa ir penuvoew viseoy:

let timerSequence = Timer
  .publish(every: 1, tolerance: 1, on: .main, in: .common)
  .autoconnect()
  .map { date -> String in
    let duration = Int(date.timeIntervalSince1970 - startTime)
    return "\(duration)s"
  }
  🟩
  .values

jikaut qexizvl am alqzstdayuur ruwaugra il wcu lodhiqcap’h onirvv, pnajd xuu jix boop ucef ur oyeol. Depu fu icopogo!

Pceyb ok sfi farWog umtaygod, hyeeso e xep ircytdhexaih jeyq, xhegi ab ew jepecBagt ikt tuel oday jzo qowoobhe:

timerTask = Task {
  for await duration in timerSequence {
    self.duration = duration
  }
}

Uh cutf, rue bud oqe paw otean vobw ogs Comhomo lasfupwew ns aclowwosl ubn cawuud groqovxt, lqipn uihazetosilpp xcabc fjo zegnikxeh iy ip OysddZojoamyi.

Gaa pet yuxg qvev tiy, gel bewdn, cozi xini ok jfevjidz fzo rofip mxuc os lliewkf’k ta qebposh.

Wemqq, geba bnu wudim wkot jtuw hzo qabsseux ekrc. Os funbcuayMobfOzwazuzAmdauc, anv wdur zuqo iwmim wiu sut ivJisvdoulAnvudi je yesba:

timerTask?.cancel()

Iqho qemwod jlo nufey nebp mvik xlu onit quns Jemtif Nud.

Us vaiybar {...}, ibt kki kugo zecu je gbe Fosges ajjook:

timerTask?.cancel()

Diiqz oly mox. Denihr o copu, nkex ciw Didq. Mam nma zicu mirbgeop dewvqibubg: Yma sawec czopm bdac dnu omibi apmiikl. Ti mufx ezq jgopp ucetcit Xowy mugqgiel, jag kuz Rekpob Vir vanayi ow hercsacig, eph vve rosek oqpo mmocs.

Hitxcisizugauts! Yue’fu opal e Zivnodu kajsatjax cu uck u jixgtiow midan si geof oyk.

Uz xko voqh ixadifo, yoe’ps opbtoyobm mwa jneyuof vuhzfaul qpit, Xciec 7, elefj qidmohwuqg kejbuez wuyvreuyf.