Dartͷഉଞ੍ޚ͓͞Β͍ͯ͠Έͨ 2022.02.22 Mobileษڧձ Wantedly × νʔϜϥϘ Bunjiro Miyoshi

About Me • νʔϜϥϘॴଐ • (ࣗশ)ϚϧνϓϥοτϑΥʔϜܳਓ • KMM, Flutter etc... • oura ringΛฆࣦͨ͠γϣοΫͰ৸ࠐΜͩ(ઌि༵ۚ೔ʹ৽͍͠ͷಧ͍ ͨ)

Outline • ࿩͢͜ͱ • Flutter(Dart VM)ͷฒྻॲཧͷجຊ • ഉଞ੍ޚΛ͏·͘΍Δ • ࿩͞ͳ͍͜ͱ • Flutter Webͷߟྀ

Concurrency of Flutter(Dart VM) • Dart͸Single ThreadɾEvent Loop(iOS, androidಉ͡) • iOS, androidΤϯδχΞ͕૝ఆ͢Δthread͸Isolateͱ͍͏୯ҐͰѻΘΕΔ • ϝϞϦͷڞ༗͸ߦ͑ͣɺϝοηʔδΛ༻͍ͯσʔλΛ΍ΓऔΓ͢Δ • https://dart.dev/guides/language/concurrency#how-isolates-work ʹ͸👇ͷه ࡌ • you don’t have to worry about mutexes or locks • ϝϞϦ͕ڞ༗͞Εͳ͍ͷͰallocͱgarbage collectʹmutex΍lock͕ඞཁͳ͍

͑ͬɺഉଞ੍ޚ͍Βͳ͍ͷʁ😳 (ࠓ೔ͷൃදͷ࢒ΓͲ͏͠Α͏ɾɾɾɾ)

IsolateΛ࢖͏ࡍͷTipsʹ͍ͭͯൃද͞ ͍ͤͯͩ͘͞🙇

Dartͷฒྻॲཧ͓͞Β͍ͯ͠Έͨ w w w w 2022.02.22 Mobileษڧձ Wantedly × νʔϜϥϘ Bunjiro Miyoshi

Basics of Isolate • جຊతʹ͸JavaͷϚϧνεϨουͷײ֮Ͱ࢖༻͢Ε͹Α͍͕͍͔ͭ͘஫ҙͨ͠΄͏͕Α ͍ • IsolateΛੜ੒͢Δࡍͷίετ͕ωΠςΟϒΑΓएׯߴ͍ • ϝϞϦ͕Isolate͝ͱʹ෼཭͞Ε͍ͯΔͷͰม਺ʹΞΫηε͢ΔܗͰॻ͍ͯ΋Main Isolateʹ͸൓ө͞Εͳ͍ • Isolate಺Ͱൃੜͨ͠error͸RemoteError or Exceptionʹϥοϓ͞ΕͨܗͰฦ٫͞ΕΔ • Isolate APIΛ௚઀࢖͏ΑΓFlutterͷcomputeΛ࢖༻͢Δͱॻ͖΍͍͢

Cost of Isolate • mono͞Μͷmedium͕Θ͔Γ΍͍͢ͷͰׂѪ • https://medium.com/ fl utter-jp/isolate-a3f6eab488b5 • ωοτϫʔΫϨεϙϯε଴ͪ౳ͷCPUෛՙ͕௿͍΋ͷʹ͍ͭͯ͸Main IsolateͰ΍ͬͨ ΄͏͕Α͍ • CPUෛՙ͕ߴ͍΋ͷ(ܭࢉΛߦ͏ϧʔϓॲཧɺେ͖͍ϑΝΠϧͷγϦΞϥΠζ)͸Isolate Λ࢖ͬͯ͋͛Δͱྑͦ͞͏ • େ͖͍ϑΝΠϧͷγϦΞϥΠζͰ΋2018೥࣌఺ͰIsolateͷεΠονϯάίετͷ΄͏ ͕ߴ͍ͭͨ͘

Access to variables in Isolate • ϝϞϦ͕Isolate͝ͱʹ෼཭͞Ε͍ͯΔͱ͍͏͜ͱ͸Isolate಺Ͱม਺Λ ߋ৽ͯ͠΋Main Isolate্Ͱ͸൓ө͞Εͳ͍ • 👆Λߟ͑ΔͱIsolate͸εϨουͱೝࣝ͢ΔΑΓϓϩηεͱೝࣝͯ͋͠ ͛Δͱ͍͍ײ͡ • ഉଞ੍ޚ͍Βͳ͍ means Main IsolateͰॱ࣍Α͠ͳʹ΍ͬͯͶ😉ͱ͍ ͏͜ͱ w w w w w w w w

Example of accessing to variables in Isolate ϝϞϦ্ͰτʔΫϯ؅ཧΛ ߦ͏Ϋϥε

Example of accessing to variables in Isolate όοΫάϥ΢ϯυεϨουͰݺ͹ΕΔ ॲཧΛ࣋ͭΫϥε

Example of accessing to variables in Isolate όοΫάϥ΢ϯυεϨουͰݺ͹ΕΔॲཧ όοΫάϥ΢ϯυεϨου্Ͱ 1. τʔΫϯͷಡΈग़͠ 2. ॲཧͷݺͼग़͠ 3. τʔΫϯͷ্ॻ͖ Λߦ͏

Example of accessing to variables in Isolate • લϖʔδͷ࣮૷Ͱ͸ผεϨουͰτʔΫϯʹΞΫηεͯ͠͠·͍ͬͯ Δ • DartͰ͸ผIsolateͰݺͼग़͞ΕΔͱߋ৽ͨ͠τʔΫϯͷ஋MainIsolate Ͱ͸औಘͰ͖ͳ͍😩 • 👉ં֯τʔΫϯߋ৽ͨ͠ͷʹ࠶౓ϝιουΛୟ͍ͨͱ͖ʹ஋͕ߋ৽͞ Ε͍ͯͳ͍ɾɾɾͳΜͯ͜ͱʹɾɾɾɾ

Example of accessing to variables in Isolate Main Isolate্Ͱॱ࣍ॲཧ͞ΕΔΑ͏ʹॲཧ Λهड़͢Δ

Example of accessing to variables in Isolate τʔΫϯಡΈग़͠ॲཧΛMain Isolate Ͱ࣮ࢪ͢ΔΑ͏ʹมߋ τʔΫϯࣗମ͸Ҿ਺ͰผIsolateͰݺ͹ ΕΔϝιουʹ౉͢ τʔΫϯॻ͖ग़͠ॲཧΛMain Isolate Ͱ࣮ࢪ͢ΔΑ͏ʹมߋ

Error in Isolate(original Isolate) • onErrorʹ౉ͨ͠SendPortʹ͸[String(Exception໊)ɺ String(StackTrace)]͕ྲྀΕͯ͘Δ • Isolate.error.listen()Ͱ͸👆ͷ৘ใΛϥοϓͨ͠RemoteError͕ྲྀΕͯ ͘Δ

Error in Isolate(original Isolate) Stringͷ഑ྻΛRemoteErrorʹม׵͠ ͍ͯΔ😩

Error in Isolate(compute) • Exceptionʹϥοϓ͞ΕΔ Exceptionʹϥοϓͯ͠Streamͷ errorʹྲྀ͍ͯ͠Δ😩

Error in Isolate(ara ara shi handling) • ϥοϓ͞Ε·ͬͯͯ͘πϥ͍ɾɾɾɾ👼 • Exception.messageͷจࣈྻ൑ఆͰΤϥʔϋϯυϦϯά͢Δ͜ͱ΋ෆ Մೳ͡Όͳ͍͕πϥ͍ɾɾɾɾ👼 • ϝϞϦόοϑΝΛߟྀͯ͠StringͷΈͰ΍ΓऔΓ͍ͯ͠Δͷ͔΋͠Ε ͳ͍͕ߥʑ͘͠ExceptionΛड͚औΔํ๏Λ໛ࡧͯ͠ΈΔ

Error in Isolate(ara ara shi handling) Isolate.spawnͰݺͼग़͢ϝιουͷҾ ਺ͷportΛ഑ྻʹͯ͠ExceptionΛྲྀ͢༻ ͷportΛड͚औΔ Isolate.spawnͷonErrorʹ͸౉ͣ͞ʹϝ ιουͷҾ਺ͱͯ͠ExceptionΛड͚औΔ Α͏ͷPortΛ౉͢

Error in Isolate(ara ara shi handling) • computeͷํ͸computeؔ਺Λࢀߟʹͯ͠લͷϖʔδͷ࣮૷Λ࢖͏֦ ுؔ਺Λ࡞ͬͯ͋͛Δ

͝੩ௌ͋Γ͕ͱ͏͍͟͝·ͨ͠

Reference • Concurrency in Dart • https://dart.dev/guides/language/concurrency#sending-multiple- messages-between-isolates • FlutterͰIsolateΛ༻͍ͨฒྻॲཧΛ͢Δ΂͖γʔϯͱͦͷ΍Γํ • https://medium.com/ fl utter-jp/isolate-a3f6eab488b5