introspection.rs - mozsearch

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use objc2::runtime::{AnyClass, NSObject};

use objc2::{sel, ClassType, Encode};

fn main() {

    // Get the class representing `NSObject`

    let cls = NSObject::class();

    // Inspect various properties of the class

    println!("NSObject superclass: {:?}", cls.superclass());

    println!("NSObject size: {}", cls.instance_size());

    println!(

        "-[NSObject alloc] would work: {}",

        cls.responds_to(sel!(alloc))

);

    println!(

        "+[NSObject alloc] would work: {}",

        cls.metaclass().responds_to(sel!(alloc))

);

    // Inspect an instance variable on the class

//

    // Note: You should not rely on the `isa` ivar being available,

    // this is only for demonstration.

    let ivar = cls

        .instance_variable(c"isa")

        .expect("no ivar with name 'isa' found on NSObject");

    println!(

        "Instance variable {:?} has type encoding {:?}",

        ivar.name(),

        ivar.type_encoding()

);

    assert!(<*const AnyClass>::ENCODING.equivalent_to_str(ivar.type_encoding().to_str().unwrap()));

    // Inspect a method of the class

    let method = cls.instance_method(sel!(hash)).unwrap();

    println!(

        "-[NSObject hash] takes {} parameters",

        method.arguments_count()

);

    let hash_return = method.return_type();

    println!("-[NSObject hash] return type: {hash_return:?}");

    assert!(usize::ENCODING.equivalent_to_str(hash_return.to_str().unwrap()));

    // Create an instance

    let obj = NSObject::new();

    println!("NSObject address: {obj:p}");

    // Read an ivar on the object

    let isa: *const AnyClass = unsafe { *ivar.load(&obj) };

    println!("NSObject isa: {isa:?}");