Struct objc2::runtime::ProtocolObject

#[repr(C)]
pub struct ProtocolObject<P: ?Sized + ProtocolType> { /* 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::Id;

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

Implementations

impl<P: ?Sized + ProtocolType> ProtocolObject<P>

pub fn from_ref<T: Message>(obj: &T) -> &Selfwhere P: ImplementedBy<T>,

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

pub fn from_mut<T: Message>(obj: &mut T) -> &mut Selfwhere P: ImplementedBy<T>,

Get a mutable type-erased reference from a type implementing a protocol.

pub fn from_id<T>(obj: Id<T>) -> Id<Self> where P: ImplementedBy<T> + 'static, T: 'static + Message,

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

Trait Implementations

impl<P, T> AsMut<ProtocolObject<T>> for ProtocolObject<P>where P: ?Sized + ProtocolType, T: ?Sized + ProtocolType + ImplementedBy<ProtocolObject<P>>,

fn as_mut(&mut self) -> &mut ProtocolObject<T>

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

impl<P, T> AsRef<ProtocolObject<T>> for ProtocolObject<P>where P: ?Sized + ProtocolType, T: ?Sized + ProtocolType + 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 + ProtocolType + NSObjectProtocol> Debug for ProtocolObject<P>

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

Formats the value using the given formatter.

impl<P: ?Sized + ProtocolType + 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<T> NSObjectProtocol for ProtocolObject<T>where T: ?Sized + ProtocolType + NSObjectProtocol,

fn is_kind_of<T: ClassType>(&self) -> boolwhere Self: Sized + Message,

Check if the object is an instance of the class, or one of it’s subclasses.

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

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

This method tests for self and other values to be equal, and is used by ==.

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

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

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

const ENCODING_REF: Encoding = Encoding::Object

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

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

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