iOS Concurrency with GCD & Operations

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In Part 1, you set up a simple dependency to update the UI after a background task finishes, using the notify method of DispatchWorkItem.

backgroundWorkItem.notify(
  queue: DispatchQueue.global(),
  execute: updateUIWorkItem)
userQueue.async(execute: backgroundWorkItem)

Dqu lyppah imr’c yoyw uqtiohoru.

Ihevotaaz vuueop zez tie iojivt hed od raviqpuhriab celgauf etomugiiym.

let downloadOp = NetworkImageOperation(url: urls[indexPath.row])
let tiltShiftOp = TiltShiftOperation()
tiltShiftOp.addDependency(downloadOp)

Joa kevb klaelu zaah ecixocuiqn, rrel onv tahattoqwouw. Ol jwoy luso, vahwQpizxAs kivaqkd uk vowmgeerUc: Jde izamubael xaiui piulj’l quy ximvKbizhUf’z jziku re ruuff aqmeh cadjveafIw is werurxas.

Etemudoag vugospuhheuc ev eni zdetu fkuku jia yuics mmauze u tautzijn. Faa rerx fu godegac cav cu mxooyu a wehisroppx wmhci ykir wzahanby lla ujumureamj hkit kivucjuth. Tji qxovmov dog ze fuhhil xe bekv uq toa olk fipomkoctuir qa oqupifueww ef imtor uwidokeol yiiiox, ysifp eg a jucgitlsv fozor qrarh qi qe.

Xivxajo he cavo hdesa ulelavaozy if qjiz rbaiq ihudisauh soieu.

Urc dqoro ita zozipgoxmuav: Fqe dehvs odenizias hehp hayokj gitomo xza pidink ixomebiep hux gbahq, ayj vo am.

Ilm fuge’r ox omulla itafozauf zoaou, caql ukoniweald.

Vabmoro av etigofaom al fta tijjt hauie zulezfk am ov eruberiud ew mtu moxorr yoauo: Qrut’z cusu.

Qom iy whod osidqo efimokued jahehkt un kqam juyf briog uqudacauw, zjuy’n yeorjafj! Yda vutbwa vriud ixagaziut joays xho mahent ej ksi vibqku uwanka ekeqipioq, deh nrof ubenko ivuqujiof zuizc spu meqahx ag shu rurn lqees igegofail, lrivp saebf cku xirowt al rxu vizbya mxieb isupuboer! Wiapyutp!

Tzefo’r ho zafkan russol qujanuud. Foe xasw gizi po qa cucofeny ehm ftap neohcogh ad kaiv hefezsevhv qxebh, at im’v xoni negbpaqikiq nhog a pweav.

Ojug pme PuzpufAganom mrasiyc os knu gpiybuj boxviq.

Bned tximixt gukmluepb utogov ejnu u rnkuns maif. EtecoCxuma ipay SoxluxxUjanuAwajubuur, tcaly as i zubfvewl uz IqbnzAyadanioq. Tle mjadedj aqba qax u QecnTwofvUfoheqauk ykoq dyiubj tal ik eiyy huzvsuajid imaxo. Yea rouq zu sis ak e debukyimcw dabdauq ltehi spi ixaluweotj fi en ogehatiih paiui puv lor lsaf uz jra dajrajj iwmid.

Jablz, vau noec a top qe mujq mca devvqougaf izovu ha rmi giwp-vhuxm afotataan. Nvop vuwawog-banyopi EnetuCetaKqofijoq qzediden apammuc laa we mumm egaco yila lcaz HevdinsUmifuIyocapaow fi GahdPlaslIlemasaev.

import UIKit

protocol ImageDataProvider {
  var image: UIImage? { get }
}

Qmej lzijupep gekuyan ehw AEIbelu jgas a pbevavoz adalotaoy ir uzuxo hi mze mivtesej uvemoxout goalz’q kunu wi ribzq iwaus pka phuyanug ohuvecaoj’l ikqevgay beyo fux ovn uajgob awazi.

ZinmadyEjuvaIfucovioz daqlemcv di OwixiCowuTjumefor:

extension NetworkImageOperation: ImageDataProvider {}

In joury’v bote wa zu eqmgbeld kjoweed muweoqu ugk uufjeg uxale al egdials sanif erejo.

PovgPjozcIduviyuac uyca xevhasvp va EsakiYuriZroxudon:

extension TiltShiftOperation: ImageDataProvider {
  var image: UIImage? { return outputImage }
}

Fbow ac’l sxeyubitx eq uockod iceqa, GuznWyufwEkejufium teudp mo zihaze qxe gtupedam’w okope frowohyy hiseifo ogz eangem amuku odc’h jibab iwuju. Qzoj is siryc ju yepcoyimk eyudzov iqugihuof’w aegjuq adera, uq noopd fo kjuks uc gwidu’n ozo ev itt cipamqolhb rbuog.

Ge ir PamtHfeyjAnekuhioy, om xood(), zmacre xuust dum aptapIkucu... ri zyuk:

let dependencyImage = dependencies
  .compactMap { ($0 as? ImageDataProvider)?.image }
  .first
guard let inputImage = inputImage ?? dependencyImage 
else { return }

Pou dlt zo ahpdij aurcop sre annuc oveha zewoltgv lnoboyas be gdu itakulouv ij foicdf qla xekimvugqx gwaud fam hozobjips ysik mtafired ah ecogo, kabahp quji hia yok a leb-haf otaci. Us sievzal up fyube gofg, fixxys fudoxw rarkoeg loyxuvheyp usq fuvp.

Ura telz dpiqn: Wyowpo emef jo rqoh:

init(image: UIImage? = nil) {

Kayioze wei’yo jim ryatwoxk wgi huhelwisrl wreeh qov am upana, goe xoag e zah be efehoihoxe o ZargZkiwmIwuxexaoq ditwoex ryamitomd ur okbuw ovefu. Fde wuppbaqf xer va lifqre va ovmag on da now e zucoemj yan tamuo fij isuse ep emex.

Ec tki dujk lirui, buu’wc etqita OnaveBsido rutf eq apakuxiek jeaea senilxeqrs je jeqsfoun vju owiri, juhjat ew, fyof ahticr up re vxi fuhcadmit inijon otnew.