Struct ProtocolObject

#[repr(C)]
pub struct ProtocolObject<P: ?Sized> { /* private fields */ }

An object representing any object that implements a specified protocol.

Objective-C has a feature where you can write id<MyProtocol>, and then work with the protocol as-if it was an object; this is very similar to dyn traits in Rust!

If we could customize how dyn Trait works, then this struct would not have been necessary; however, dyn Trait is a wide pointer with overhead, which this struct helps avoid.

If the trait T inherits NSObjectProtocol, this will implement common traits like Debug, PartialEq, Eq and Hash.

Example

Convert an object MyObject that implements the a protocol MyProtocol into a ProtocolObject for working with the protocol in a type-erased way.

use objc2::runtime::ProtocolObject;
use objc2::rc::Retained;

let obj: Retained<MyObject> = MyObject::new();
let proto: &ProtocolObject<dyn MyProtocol> = ProtocolObject::from_ref(&*obj);
let proto: Retained<ProtocolObject<dyn MyProtocol>> = ProtocolObject::from_retained(obj);

Implementations

impl<P: ?Sized> ProtocolObject<P>

pub fn from_ref<T: ?Sized + Message>(obj: &T) -> &Self

where P: ImplementedBy<T>,

Get an immutable type-erased reference from a type implementing a protocol.

pub fn from_id<T>(obj: Retained<T>) -> Retained<Self>

where P: ImplementedBy<T> + 'static, T: Message + 'static,

👎Deprecated: use ProtocolObject::from_retained instead

Get a type-erased object from a type implementing a protocol.

pub fn from_retained<T>(obj: Retained<T>) -> Retained<Self>

where P: ImplementedBy<T> + 'static, T: Message + 'static,

Get a type-erased object from a type implementing a protocol.

Trait Implementations

impl<P: ?Sized + 'static> AsRef<AnyObject> for ProtocolObject<P>

fn as_ref(&self) -> &AnyObject

Converts this type into a shared reference of the (usually inferred) input type.

impl<P: ?Sized, T> AsRef<ProtocolObject<T>> for ProtocolObject<P>

where T: ?Sized + ImplementedBy<ProtocolObject<P>>,

fn as_ref(&self) -> &ProtocolObject<T>

Converts this type into a shared reference of the (usually inferred) input type.

impl<P: ?Sized + NSObjectProtocol> Debug for ProtocolObject<P>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<P: ?Sized + NSObjectProtocol> Hash for ProtocolObject<P>

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<P: ?Sized + MainThreadOnly> MainThreadOnly for ProtocolObject<P>

fn mtm(&self) -> MainThreadMarker

Get a MainThreadMarker from the main-thread-only object.

impl<P: ?Sized> Message for ProtocolObject<P>

fn retain(&self) -> Retained<Self>

where Self: Sized,

Increment the reference count of the receiver.

impl<T> NSObjectProtocol for ProtocolObject<T>

where T: ?Sized + NSObjectProtocol,

fn isEqual(&self, other: Option<&AnyObject>) -> bool

where Self: Sized + Message,

Check whether the object is equal to an arbitrary other object.

fn hash(&self) -> NSUInteger

where Self: Sized + Message,

An integer that can be used as a table address in a hash table structure.

fn isKindOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of the class, or one of its subclasses.

fn is_kind_of<T: ClassType>(&self) -> bool

where Self: Sized + Message,

👎Deprecated: use isKindOfClass directly, or cast your objects with AnyObject::downcast_ref

Check if the object is an instance of the class type, or one of its subclasses.

fn isMemberOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of a specific class, without checking subclasses.

fn respondsToSelector(&self, aSelector: Sel) -> bool

where Self: Sized + Message,

Check whether the object implements or inherits a method with the given selector.

fn conformsToProtocol(&self, aProtocol: &AnyProtocol) -> bool

where Self: Sized + Message,

Check whether the object conforms to a given protocol.

fn description(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object.

fn debugDescription(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object to use when debugging.

fn isProxy(&self) -> bool

where Self: Sized + Message,

Check whether the receiver is a subclass of the NSProxy root class instead of the usual NSObject.

fn retainCount(&self) -> NSUInteger

where Self: Sized + Message,

The reference count of the object.

impl<P: ?Sized + NSObjectProtocol> PartialEq for ProtocolObject<P>

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<P: ?Sized> RefEncode for ProtocolObject<P>

const ENCODING_REF: Encoding = Encoding::Object

The Objective-C type-encoding for a reference of this type.

impl<P: ?Sized + AnyThread> AnyThread for ProtocolObject<P>

impl<P: ?Sized + NSObjectProtocol> Eq for ProtocolObject<P>

impl<P: ?Sized + Send> Send for ProtocolObject<P>

impl<P: ?Sized + Sync> Sync for ProtocolObject<P>