Speed up iOS Development with LLDB Code Injection and Framework Live Preview

ChienJu Lin
LINE Taiwan Engineering 7 iOS Developer
https://linedevday.linecorp.com/jp/2019/sessions/S2-8

Transcript

1. 2019 DevDay
   Speed Up iOS Development With
   LLDB Code Injection and
   Framework Live Preview
   > ChienJu Lin
   > LINE Taiwan Engineering 7 iOS Developer
   

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2. General Development Flow
   Product
   Verify
   Dev
   Spec
   Build
   

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3. Pain Point - Long Build Time
   Product
   Dev
   Spec
   Build Verify
   

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4. Reduce Number of Times

   To Rebuild Whole App
   

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5. Build only the module that currently working on
   Less Compile Source Count
   Only Build the Framework
   Less Build Time
   

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6. > Not embedded/linked by others
   Clean refactoring might need lots of works
   Tips for Existing Projects
   Apply Dummy Framework First
   Easier To Apply, Refactor Afterwards
   

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7. How To Verify VIEW in Framework?
   

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8. > No need many scrolls and clicks
   > Preview with different language / device size
   Interactive
   Fast Access
   Preview Under Different Environment
   SwiftUI / Playground Live Preview
   > Preview in different view state
   

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9. How To Verify LOGIC in Framework?
   

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10. Test Driven Development in Playground
    To build faster at every iteration
    Write Failing Test
    Make It Pass
    Refactor
    Unit Tests / TDD are best to verify logic
    > Unit Test the framework in playground for
    interactive environment
    > Move to test target for CI after completion
    

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11. How To Speed Up Whole App Verification?
    

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12. LLDB Code Injection
    Modify control flow without rebuild
    Inject new code using LLDB Command
    

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13. LLDB Code Injection - Example
    Goal: Inject new view model to asynchronously download
    

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14. LLDB Code Injection - Example
    1. Insert breakpoint, enter multi-line expression mode
    

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15. LLDB Code Injection - Example
    2. Inject new view model code
    

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16. LLDB Code Injection - Example
    3. Execute the injected function
    

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17. LLDB Code Injection - Example
    4. Wait the async task to complete. Retrigger the breakpoint, check result & Done.
    

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18. Framework Code
    Injection
    Preview
    Summary
    

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19. Reduce Number of Times

    To Rebuild Whole App
    

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20. Thank You
    

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