Advanced guard of DeallocationChecker

Advanced guard of DeallocationChecker
potatotips #66 at Yappli

Referenced URLs:
- https://github.com/fastred/DeallocationChecker
- https://speakerdeck.com/corin8823/iosdc-2018-memory-leak

Transcript

1. "EWBODFEHVBSEPG
   DeallocationChecker
   11/11 potatotips #66
   taiki komaba(@r_plus)
   

   View Slide

2. UBJLJLPNBCB
   !S@QMVT
   
   

   View Slide

3. DeallocationChecker
   HJUIVCDPNGBTUSFE%FBMMPDBUJPO$IFDLFS
   EJTQBUDIBGUFS

   View Slide

4. DeallocationChecker
   viewDidDisappear(_:)࣌ʹͦΕΛ࣮ߦ͢ΔͱϦʔΫνΣοΫग़དྷΔ
   ˠνΣοΫ͍ͨ͠WJFXDPOUSPMMFSຖʹݸผʹ࣮ߦ͢Δඞཁ͕͋Δ
   

   View Slide

5. ΊΜͲ͍
   

   View Slide

6. ࣗಈνΣοΫ΁
   J04%$ͷ!DPSJO͞Μͷૉ੖Β͍͠-5ʮ໌೔͔Β࢖͑Δ
   7JFX$POUSPMMFSͷ.FNPSZ-FBLݕग़ʯΛࢀর
   IUUQTTQFBLFSEFDLDPNDPSJOJPTEDNFNPSZMFBL
   ʮviewDidDisappear(_:)Λ.FUIPE4XJ[[MJOHͯ͠શͯͷWJFXDPOUSPMMFSΛࣗ
   ಈͰ%FBMMPDBUJPO$IFDLFSͷνΣοΫର৅ʹ͠Α͏ʂʯͱ͍͏࿩
   

   View Slide

7. White list view controllers
   Ͱ΋ɺେମ͍͔ͭ͘ྫ֎తͳWJFXDPOUSPMMFS͕ग़ͯ͘Δ
   ্λϒతͳ΍ͭͷWJFXDPOUSPMMFSͱ͔
   Α͘Θ͔ΒΜ4ZTUFN͕࢖ͬͯΔͬΆ͍6*,JUͷ΋ͷͱ͔
   

   View Slide

8. White list view controllers
   ˣͷ༷ʹνΣοΫલʹHVBSEΛೖΕΔ͜ͱʹͳΔ
   

   View Slide

9. ର৅͕૿͑Δ౓ λϒ͕૿͑Δ౓
   
   ʹϝϯς͢Δͷ͕ΊΜͲ͍
   ʢ௥Ճ͢Δͷ͕ɺͱ͍͏ΑΓ͸ͦΕΛઆ໌ͨ͠Γ
   ஌Βͳͯͭ͘·ͬͯ͠·͍ແବͳ࣌ؒΛ࢖Θͤͯ͠·ͬͨΓ͢Δࣄ͕ɻʣ
   

   View Slide

10. White list view controllers
    ͜ͷ΁ΜͷHVBSE XIJUFMJTU
    Λ͏·͍ࣄ΍Γ͍ͨ
    ΋ͷʹΑͬͯ͸QSPUPDPM࢖͏ํ๏΋͋Δ͚Ͳࠓճ͸ผख๏
    

    View Slide

11. "EWBODFEHVBSEPG
    DeallocationChecker
    

    View Slide

12. Pattern of white list
    λϒత7$ͷ࣮૷͸λϒ੾ସͯ͠΋࠶࡞੒͠ͳͯ͘ྑ͍༷ʹอ༗ͯ͠
    Δˡ͜Ε͕νΣοΫʹͻ͔͔ͬΔݪҼͰ΋͋Δ
    େମͷ࣮૷͸DPOUBJOFSWJFXDPOUSPMMFSͷparent͕ࣗ෼Λอ༗ͯ͠
    Δߏ੒
    $POUBJOFSWJFXDPOUSPMMFS͕ϦʔΫνΣοΫʹೖΔલʹparent͕ࣗ
    ෼Λอ༗͍ͯͨ͠Βର৅֎ʹ͍ͨ͠
    ͔͠͠ viewDidDisappear(_:)ͷͱ͖ʹ͸طʹparentϓϩύςΟ͸OJM
    

    View Slide

13. Pattern of white list
    ද͕ࣔ੾ΓସΘΔ࣌ʹparent͕ࣗ਎Λอ༗͍ͯ͠Δ͔อଘ͍ͨ͠
    ͦΕΛ΋ͬͯνΣοΫର৅֎ʹ͢Ε͹λϒͷ7$Λ໢ཏͰ͖Δ
    

    View Slide

14. Pattern of white list
    ද͕ࣔ੾ΓସΘΔ࣌ʹ
    parent͕OJMͰ͸ͳ͍λΠϛϯάͰ͋Δ
    removeFromParent(:_) ΛTXJ[[MF
    parent͕ࣗ਎Λอ༗͍ͯ͠Δ͔อଘ͍ͨ͠
    Mirrorobjc_{get,set}AssociatedObject
    

    View Slide

15. Swizzle
    

    View Slide

16. objc_{get,set}AssociatedObject
    

    View Slide

17. Mirror
    parentQSPQFSUZͷܕ͸UIViewController? Ͱ͋ΔͷͰɺͲΜͳܗ
    ࣜͰTUPSFEQSPQFSUZʹอଘ͞Ε͍ͯΔ͔Θ͔Βͳ͍
    ͦ͜ͰMirrorΛར༻͠ϦϑϨΫγϣϯͰTUPSFEQSPQFSUZΛ૸ࠪ
    ͢Δ
    

    View Slide

18. Mirror
    ୯७ͳTUPSFEQSPQFSUZ
    

    View Slide

19. Mirror
    "SSBZͰอ༗ ͜Ε͕ຆͲ
    
    

    View Slide

20. Mirror
    %JDUͰอ༗ ݟͨ͜ͱͳ͍
    
    

    View Slide

21. Simplified guard
    Ҏ্Swizzling AssociatedObject MirrorͷͭΛ
    ૊Έ߹ΘͤΔͱʜ
    

    View Slide

22. Simplified guard
    ͜ͷHVBSEୡ͕ʜ
    

    View Slide

23. Simplified guard
    ߦͰεοΩϦʂλϒͷ૿ݮʹ΋ࣗಈతʹରԠ
    

    View Slide

24. Recap
    ▸ λϒతͳview controllerͰchild view controllerΛอ༗
    ͯ͠Δέʔεʹ͓͍ͯɺλϒ੾ସ࣌ʹdeinit͞Ε͍ͯͳ
    ͍ͷ͸ϝϞϦϦʔΫͰ͸ͳ͍ʢద੾ʹͳ͍ͬͯΕ͹ʣ
    ▸ Swizzling, AssociatedObject, MirrorΛ૊Έ߹ΘͤΕ͹
    parentͷܕ͕ෆ໌Ͱ΋stored propertyʹࣗ਎Λอ༗͠
    ͍ͯΕ͹แׅతʹϦʔΫνΣοΫର৅֎ͱग़དྷΔ
    

    View Slide

25. ͓ΘΓ
    

    View Slide