Struct WKWebExtensionMessagePort

Source

#[repr(C)]
pub struct WKWebExtensionMessagePort { /* private fields */ }

Available on crate feature WKWebExtensionMessagePort only.

Expand description

A WKWebExtensionMessagePort object manages message-based communication with a web extension.

Contains properties and methods to handle message exchanges with a web extension.

Implementations§

Source §

pub unsafe fn applicationIdentifier(&self) -> Option<Retained<NSString>>

The unique identifier for the app to which this port should be connected.

This identifier is provided by the web extension and may or may not be used by the app. It’s up to the app to decide how to interpret this identifier.

Source

pub unsafe fn messageHandler( &self, ) -> mut DynBlock<dyn Fn(mut AnyObject, *mut NSError)>

Available on crate feature block2 only.

The block to be executed when a message is received from the web extension.

An optional block to be invoked when a message is received, taking two parameters: the message and an optional error.

Source

pub unsafe fn setMessageHandler( &self, message_handler: Option<&DynBlock<dyn Fn(mut AnyObject, mut NSError)>>, )

Available on crate feature block2 only.

Setter for messageHandler.

Source

pub unsafe fn disconnectHandler(&self) -> mut DynBlock<dyn Fn(mut NSError)>

Available on crate feature block2 only.

The block to be executed when the port disconnects.

An optional block to be invoked when the port disconnects, taking an optional error that indicates if the disconnection was caused by an error.

Source

pub unsafe fn setDisconnectHandler( &self, disconnect_handler: Option<&DynBlock<dyn Fn(*mut NSError)>>, )

Available on crate feature block2 only.

Setter for disconnectHandler.

Source

pub unsafe fn isDisconnected(&self) -> bool

Indicates whether the message port is disconnected.

Source

pub unsafe fn sendMessage_completionHandler( &self, message: Option<&AnyObject>, completion_handler: Option<&DynBlock<dyn Fn(*mut NSError)>>, )

Available on crate feature block2 only.

Sends a message to the connected web extension.

Parameter message: The JSON-serializable message to be sent.

Parameter completionHandler: An optional block to be invoked after the message is sent, taking an optional error.

Note: The message must be JSON-serializable according to NSJSONSerialization.

Source

pub unsafe fn disconnect(&self)

Disconnects the port, terminating all further messages.

Source

pub unsafe fn disconnectWithError(&self, error: Option<&NSError>)

Disconnects the port, terminating all further messages with an optional error.

Parameter error: An optional error indicating the reason for disconnection.

Methods from Deref<Target = NSObject>§

Source

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

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>§

Source

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

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());

Source

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

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

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.

Source

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

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`
    }
}