Struct TKTokenWatcher

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pub struct TKTokenWatcher { /* private fields */ }

Available on crate feature TKTokenWatcher only.

Expand description

Apple’s documentation

Implementations§

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impl TKTokenWatcher

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pub unsafe fn tokenIDs(&self) -> Retained<NSArray<NSString>>

Array of currently known TokenIDs in the system. Tokens are identified by instance’s names. It is possible to use KVO to be notified about token arrivals and removals.

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pub unsafe fn init(this: Allocated<Self>) -> Retained<Self>

Init watcher

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pub unsafe fn initWithInsertionHandler( this: Allocated<Self>, insertion_handler: &DynBlock<dyn Fn(NonNull<NSString>)>, ) -> Retained<Self>

👎Deprecated

Available on crate feature block2 only.

Init watcher with insertion handler

init watcher with insertion handler which is called when a new token arrives

Parameter insertionHandler: called when a new token is inserted

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pub unsafe fn setInsertionHandler( &self, insertion_handler: &DynBlock<dyn Fn(NonNull<NSString>)>, )

Available on crate feature block2 only.

Set insertion handler

when an insertion handler is set the TokenWatcher will call this handler when new token appears in the system. TokenWatcher will call the handler also for tokens which was registered in the system before the handler was set.

Parameter insertionHandler: called when a new token is inserted

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pub unsafe fn addRemovalHandler_forTokenID( &self, removal_handler: &DynBlock<dyn Fn(NonNull<NSString>)>, token_id: &NSString, )

Available on crate feature block2 only.

Add removal watcher for specific tokenID

after removalHandler for a specific tokenID is called the reference to this handler is removed. For one tokenID just one handler can be added, so next call to addRemovalHandler will replace previous handler

Parameter removalHandler: called when a token is removed

Parameter tokenID: specified tokenID, if tokenID does not exist removal handler is called imediately

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pub unsafe fn tokenInfoForTokenID( &self, token_id: &NSString, ) -> Option<Retained<TKTokenWatcherTokenInfo>>

Return TokenInfo for specific tokenID

Parameter tokenID: specified tokenID

Returns: A TokenInfo object, or nil if tokenID does not exist

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impl TKTokenWatcher

Methods declared on superclass NSObject.

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pub unsafe fn new() -> Retained<Self>

Methods from Deref<Target = NSObject>§

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pub fn doesNotRecognizeSelector(&self, sel: Sel) -> !

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>§

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pub fn class(&self) -> &'static AnyClass

Available on crate feature TKToken only.

Dynamically find the class of this object.

§Panics

May panic if the object is invalid (which may be the case for objects returned from unavailable init/new methods).

§Example

Check that an instance of NSObject has the precise class NSObject.

use objc2::ClassType;
use objc2::runtime::NSObject;

let obj = NSObject::new();
assert_eq!(obj.class(), NSObject::class());

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pub unsafe fn get_ivar<T>(&self, name: &str) -> &T
where T: Encode,

👎Deprecated: this is difficult to use correctly, use Ivar::load instead.

Available on crate feature TKToken only.

Use Ivar::load instead.

§Safety

The object must have an instance variable with the given name, and it must be of type T.

See Ivar::load_ptr for details surrounding this.

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pub fn downcast_ref<T>(&self) -> Option<&T>
where T: DowncastTarget,

Available on crate feature TKToken only.

Attempt to downcast the object to a class of type T.

This is the reference-variant. Use Retained::downcast if you want to convert a retained object to another type.

§Mutable classes

Some classes have immutable and mutable variants, such as NSString and NSMutableString.

When some Objective-C API signature says it gives you an immutable class, it generally expects you to not mutate that, even though it may technically be mutable “under the hood”.

So using this method to convert a NSString to a NSMutableString, while not unsound, is generally frowned upon unless you created the string yourself, or the API explicitly documents the string to be mutable.

See Apple’s documentation on mutability and on isKindOfClass: for more details.

§Generic classes

Objective-C generics are called “lightweight generics”, and that’s because they aren’t exposed in the runtime. This makes it impossible to safely downcast to generic collections, so this is disallowed by this method.

You can, however, safely downcast to generic collections where all the type-parameters are AnyObject.

§Panics

This works internally by calling isKindOfClass:. That means that the object must have the instance method of that name, and an exception will be thrown (if CoreFoundation is linked) or the process will abort if that is not the case. In the vast majority of cases, you don’t need to worry about this, since both root objects NSObject and NSProxy implement this method.

§Examples

Cast an NSString back and forth from NSObject.

use objc2::rc::Retained;
use objc2_foundation::{NSObject, NSString};

let obj: Retained<NSObject> = NSString::new().into_super();
let string = obj.downcast_ref::<NSString>().unwrap();
// Or with `downcast`, if we do not need the object afterwards
let string = obj.downcast::<NSString>().unwrap();

Try (and fail) to cast an NSObject to an NSString.

use objc2_foundation::{NSObject, NSString};

let obj = NSObject::new();
assert!(obj.downcast_ref::<NSString>().is_none());

Try to cast to an array of strings.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);
// This is invalid and doesn't type check.
let arr = arr.downcast_ref::<NSArray<NSString>>();

This fails to compile, since it would require enumerating over the array to ensure that each element is of the desired type, which is a performance pitfall.

Downcast when processing each element instead.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);

for elem in arr {
    if let Some(data) = elem.downcast_ref::<NSString>() {
        // handle `data`
    }
}