Kotlin Nativeにおけるfrozen状態と並行処理について

Flutter × Kotlin Multiplatform by CyberAgent #2の登壇資料です。

Transcript

1. Sato Shun Tapple, inc. Kotlin Nativeͷfrozenͱ ฒߦॲཧʹ͍ͭͯ
2. લఏ஌ࣝ • ଟগͷKotlinͷ஌ࣝ
3. ໨࣍ • ͦ΋ͦ΋ͷฒߦॲཧͷ೉͍͠ॴ • Kotlin NativeͰ͸ͲͷΑ͏ʹͯ͠ɺ͜ͷ՝୊Λղܾ͔ͨ͠ • Kotlin Nativeͷฒߦॲཧ
4. ฒߦॲཧͷ೉͍͠ॴ • mutableͳΠϯελϯεΛෳ਺εϨου͔Βૢ࡞͢Δ࣌ • synchronized΍ɺmutexͳͲͷϩοΫΛ࢖͏ • AtomicܥͷAPIΛ࢖͏ • બ୒ࢶ΋ଟ͘ɺద੾ʹॻ͘͜ͱ͸೉͍͠ • ·ͨόά͕ى͖ͨ࣌ʹ࠶ݱੑ͕௿͘ɺݪҼͷಛఆ͕ࠔ೉
5. ฒߦॲཧͷ೉͍͠ॴ • ͦ͜ͰKotlin NativeʢiOSଆʣͰ͸ɺmutableͳঢ়ଶͷΠϯελϯεʹର͠ ͯɺͱ͋Δ੍໿Λઃ͚Δ͜ͱͰղܾΛ໨ࢦͨ͠
6. shared XOR mutable੍໿ • ฒߦॲཧͰ໰୊͕ग़Δɺshared ͔ͭ mutableͳঢ়ଶΛڐՄ͠ͳ͍ͱ͍͏੍ ໿ • RustͳͲͰ΋࢖ΘΕ͍ͯΔ੍໿ʢΒ͍͠ʣ • ͜ͷ੍໿Λຬͨͨ͢ΊʹɺKotlin NativeͰ͸ frozenঢ়ଶ Λಋೖͨ͠
7. frozenঢ়ଶ? • ͦͷΠϯελϯε͕immutableͰ͋Δ͜ͱΛอূ͢Δ
8. frozenঢ়ଶ? • ͦͷΠϯελϯε͕immutableͰ͋Δ͜ͱΛอূ͢Δ /** * Freezes object subgraph reachable from this object. Frozen objects can be freely * shared between threads/workers. * * @throws FreezingException if freezing is not possible * @return the object itself * @see ensureNeverFrozen */ public fun <T> T.freeze(): T
9. frozenঢ়ଶ? • ͦͷΠϯελϯε͕immutableͰ͋Δ͜ͱΛอূ͢Δ • freezeͨ͠ΠϯελϯεΛมߋ͠Α͏ͱ͢ΔͱɺΫϥογϡ͢Δ • ଞͷεϨουͱ҆શʹڞ༗͢Δ͜ͱ͕ग़དྷΔ
10. frozenঢ়ଶ? • ͦͷΠϯελϯε͕immutableͰ͋Δ͜ͱΛอূ͢Δ • freezeͨ͠ΠϯελϯεΛมߋ͠Α͏ͱ͢ΔͱɺΫϥογϡ͢Δ • ଞͷεϨουͱ҆શʹڞ༗͢Δ͜ͱ͕ग़དྷΔ /** * Checks if given object is null or frozen or permanent (i.e. instantiated at compile-time). * * @return true if given object is null or frozen or permanent */ public val Any ?. isFrozen
11. frozenঢ়ଶ? • ͦͷΠϯελϯε͕immutableͰ͋Δ͜ͱΛอূ͢Δ • freezeͨ͠ΠϯελϯεΛมߋ͠Α͏ͱ͢ΔͱɺΫϥογϡ͢Δ • ଞͷεϨουͱ҆શʹڞ༗͢Δ͜ͱ͕ग़དྷΔ • unfreeze͸ଘࡏ͠ͳ͍
12. val sample = Sample(3) sample.i + + sample.freeze() sample.i + +
13. val sample = Sample(3) sample.i + + sample.freeze() sample.i + + Uncaught Kotlin exception: kotlin.native.concurrent.InvalidMutabilityException
14. KMMͷfrozenͷ໰୊఺ • JVM(Android)ͱNative(iOS)Ͱڍಈ͕ҟͳΔ • JVMʹ͸frozenঢ়ଶͱ͍͏֓೦͸ͳ͍ • AndroidͰ͸ಈ͘ɺ͔͠͠iOSͰ͸Ϋϥογϡ͢ΔɻΈ͍ͨͳ͜ͱ͕ى͜ ΔՄೳੑ͕͋Δ • ·ͨɺKotlin NativeͰ͸freezeΛ໌ࣔతʹݺ͹ͳͯ͘΋ɺ҉໧తʹfreeze͠ ͯ͠·͏ύλʔϯ͕͋Δ
15. ҉໧తͳfreeze • objectɺcompanion objectͳͲ͸ɺࣗಈͰfreeze͢Δ࢓༷ʹͳ͍ͬͯΔ
16. object DefaultGlobalState { private var i = 5 fun countUp() { i ++ } }
17. object DefaultGlobalState { private var i = 5 fun countUp() { i ++ } } Uncaught Kotlin exception: kotlin.native.concurrent.InvalidMutabilityException
18. @ThreadLocal object DefaultGlobalState { private var i = 5 fun countUp() { i ++ } }
19. ͜͜·Ͱͷ·ͱΊ • shared XOR mutableΛຬͨͨ͢Ίʹfrozen͕ಋೖ͞Εͨ • frozenঢ়ଶʹ͢Δ͜ͱͰɺimmutableͳঢ়ଶΛදݱͰ͖Δ • ͜Ε͸ฒྻॲཧΛ҆શʹѻ͏͜ͱ͕ग़དྷΔ • ͔͠͠ɺ҉໧తͳfrozenͳͲͰɺiOS͚ͩಈ͔ͳ͍Մೳੑ͕͋Δ
20. Kotlin Nativeͷฒߦॲཧ • ௿ϨϕϧAPIͱͯ͠ɺWorkerΫϥε͕༻ҙ͞Ε͍ͯΔ • JavaͰ͍͏ͱ͜ΖͷThreadΫϥε • Kotlin NativeͰ͸ɺجຊతʹεϨου͕มΘΔ৔߹ɺfrozenঢ়ଶʹͯ͠ immutableʹ͢Δඞཁ͕͋Δ
21. val worker = Worker.start() worker.execute(TransferMode.SAFE, { … }) { … }
22. val worker = Worker.start() worker.execute(TransferMode.SAFE, { … }) { … } public fun <T1, T2> execute( mode: TransferMode, producer: () -> T1, @VolatileLambda job: (T1) - > T2 ): Future<T2>
23. data class Sample(var i: Int) val sample = Sample(1)
24. data class Sample(var i: Int) val sample = Sample(1) worker.execute(TransferMode.SAFE, { sample }) { println(it) }
25. data class Sample(var i: Int) val sample = Sample(1) worker.execute(TransferMode.SAFE, { sample }) { println(it) } Uncaught Kotlin exception: kotlin.IllegalStateException: Illegal transfer state
26. data class Sample(var i: Int) val sample = Sample(1) worker.execute(TransferMode.SAFE, { sample.freeze() }) { println(it) }
27. data class Sample(var i: Int) val sample = Sample(1) val sample2 = Sample(2)
28. data class Sample(var i: Int) val sample = Sample(1) val sample2 = Sample(2) worker.execute(TransferMode.SAFE, { sample.freeze() }) { println(it) }
29. data class Sample(var i: Int) val sample = Sample(1) val sample2 = Sample(2) fun background(block: () -> Unit) { worker.execute(TransferMode.SAFE, { block.freeze() }) { it() } }
30. data class Sample(var i: Int) val sample = Sample(1) val sample2 = Sample(2) background { println(sample) println(sample2) } fun background(block: () -> Unit) { worker.execute(TransferMode.SAFE, { block.freeze() }) { it() } }
31. data class Sample(var i: Int) val sample = Sample(1) val sample2 = Sample(2) background { println(sample) println(sample2) } fun background(block: () -> Unit) { worker.execute(TransferMode.SAFE, { block.freeze() }) { it() } } sampleɺsample2ຊମΛfreeze͍ͯ͠ͳ͍ εϨου͕มΘΔ৔߹͸ɺfreeze͠ͳ͍ͱ͍͚ͳ͍ͷͰ͸?
32. data class Sample(var i: Int) val sample = Sample(1) val sample2 = Sample(2) background { println(sample) println(sample2) } fun background(block: () -> Unit) { worker.execute(TransferMode.SAFE, { block.freeze() }) { it() } } sampleɺsample2ຊମΛfreeze͍ͯ͠ͳ͍ εϨου͕มΘΔ৔߹͸ɺfreeze͠ͳ͍ͱ͍͚ͳ͍ͷͰ͸? ϥϜμຊମΛfreeze͢Δͱɺ ͦͷϥϜμ͕ࢀর͍ͯ͠Δม਺΋࿈࠯తʹfreeze͞ΕΔ
33. Kotlin Nativeͷฒߦॲཧͷ·ͱΊ • Kotlin Nativeʹ͸Workerͱ͍͏௿ϨϕϧAPI͕༻ҙ͞Ε͍ͯΔ • εϨουؒΛލ͙ͱ͖͸ɺfreeze͢Δඞཁ͕͋Δ • ͋ΔΠϯελϯεΛfreeze͢Δͱɺࢀর͞Ε͍ͯΔΠϯελϯε΋࿈࠯త ʹfreeze͢Δ
34. ͓·͚: Coroutineʹ͍ͭͯ • ࣮ࡍͷ։ൃͰ͸ɺCoroutineͳͲͷߴϨϕϧͳAPIΛ࢖͏͜ͱ͕ଟ͍ • ݱঢ়ɺKotlin Nativeʹ͓͚ΔCoroutine͸ʮ୯ҰεϨουʹͷΈରԠͨ͠௨ ৗόʔδϣϯʯͱʮෳ਺εϨουʹରԠͨ͠όʔδϣϯʯ͕͋Δ
35. val sample = Sample("1") println(sample.isFrozen) withContext(Dispatchers.Default) { println(sample.isFrozen) }
36. val sample = Sample("1") println(sample.isFrozen) withContext(Dispatchers.Default) { println(sample.isFrozen) } ୯ҰεϨουόʔδϣϯͷCoroutineͷ৔߹͸ɺisFrozen͸falseɺ ෳ਺εϨουόʔδϣϯͷCoroutineͷ৔߹͸ɺisFrozen͸true
37. ͝ਗ਼ௌ͋Γ͕ͱ͏͍͟͝·ͨ͠