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ios.md

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iOS

  • Hardware

    • x86_64-darwin
    • arm64-darwin
    • x86_64-ios (simulator)
    • arm64-ios (physical device)

  • Core OS

  • Core Services

  • Media

  • Cocoa Touch > UIKit

  • Applications

  • Lazy var

    • Swift has a mechanism built right into the language that enables just-in-time calculation of expensive work, and it is called a lazy variable.
    • A lazy stored property is a property whose initial value is not calculated until the first time it is used.
    • You indicate a lazy stored property by writing the lazy modifier before its declaration.

  • Closure

    • Functions are a special case of closures: blocks of code that can be called later.
    • The code in a closure has access to things like variables and functions that were available in the scope where the closure was created, even if the closure is in a different scope when it is executed.
    • You can write a closure without a name by surrounding code with braces ({}). Use in to separate the arguments and return type from the body.

  • ARC

    • ARC is a compile-time feature that is Apple's version of automated memory management.
    • It stands for Automatic Reference Counting. This means that it only frees up memory for objects when there are zero strong references to them.

  • Notification Center

    • When communication between two or more components of your app, that have no formal connection, needs to happen
    • When communication needs to happen repeatedly and consistently
    • When using one-to-many or many-to-many communication

  • Reactive

    • Async
    • Behaviour
    • Publish
    • Reply

  • Interaction with c always takes an opaque pointer in new systems, in older systems worked differently.

  • Concurrency

    • serial queue
      • The main thread queue is a serial queue
      • using sync in the serial queue will cause deadlock
    • parallel queue
    • reference-counting (i.e. xref).
    • The large negative value for xref and ref, for example, is likely indicating that is an object that cannot be deallocated.

  • Can capture memory leaks by enabling option.

# device listing
rvictl -l

# packet capture
rvictl -s INDETIFIER_OF_DEVICE

# remove the virtual interface
rvictl -x <UDID>

# Capture packet
tcpdump -n -t -i rvi0 -q -A tcp

References