Struct NSValue

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

Available on crate feature NSValue only.

Apple’s documentation

Implementations

impl NSValue

NSValueGeometryExtensions.

pub unsafe fn valueWithPoint(point: NSPoint) -> Retained<NSValue>

Available on crate features NSGeometry and objc2-core-foundation only.

pub unsafe fn valueWithSize(size: NSSize) -> Retained<NSValue>

Available on crate features NSGeometry and objc2-core-foundation only.

pub unsafe fn valueWithRect(rect: NSRect) -> Retained<NSValue>

Available on crate features NSGeometry and objc2-core-foundation only.

pub unsafe fn valueWithEdgeInsets(insets: NSEdgeInsets) -> Retained<NSValue>

Available on crate features NSGeometry and objc2-core-foundation only.

pub unsafe fn pointValue(&self) -> NSPoint

Available on crate features NSGeometry and objc2-core-foundation only.

pub unsafe fn sizeValue(&self) -> NSSize

Available on crate features NSGeometry and objc2-core-foundation only.

pub unsafe fn rectValue(&self) -> NSRect

Available on crate features NSGeometry and objc2-core-foundation only.

pub unsafe fn edgeInsetsValue(&self) -> NSEdgeInsets

Available on crate features NSGeometry and objc2-core-foundation only.

impl NSValue

NSValueRangeExtensions.

pub unsafe fn valueWithRange(range: NSRange) -> Retained<NSValue>

Available on crate feature NSRange only.

pub unsafe fn rangeValue(&self) -> NSRange

Available on crate feature NSRange only.

impl NSValue

pub unsafe fn getValue_size(&self, value: NonNull<c_void>, size: NSUInteger)

pub fn objCType(&self) -> NonNull<c_char>

pub unsafe fn initWithBytes_objCType( this: Allocated<Self>, value: NonNull<c_void>, type: NonNull<c_char>, ) -> Retained<Self>

pub unsafe fn initWithCoder( this: Allocated<Self>, coder: &NSCoder, ) -> Option<Retained<Self>>

Available on crate feature NSCoder only.

impl NSValue

NSValueCreation.

pub unsafe fn valueWithBytes_objCType( value: NonNull<c_void>, type: NonNull<c_char>, ) -> Retained<NSValue>

pub unsafe fn value_withObjCType( value: NonNull<c_void>, type: NonNull<c_char>, ) -> Retained<NSValue>

impl NSValue

NSValueExtensionMethods.

pub unsafe fn valueWithNonretainedObject( an_object: Option<&AnyObject>, ) -> Retained<NSValue>

pub unsafe fn nonretainedObjectValue(&self) -> Option<Retained<AnyObject>>

pub unsafe fn valueWithPointer(pointer: *const c_void) -> Retained<NSValue>

pub unsafe fn pointerValue(&self) -> *mut c_void

pub fn isEqualToValue(&self, value: &NSValue) -> bool

impl NSValue

NSDeprecated.

pub unsafe fn getValue(&self, value: NonNull<c_void>)

👎Deprecated

impl NSValue

Creation methods.

pub fn new<T: 'static + Copy + Encode>(value: T) -> Retained<Self>

Create a new NSValue containing the given type.

Be careful when using this since you may accidentally pass a reference when you wanted to pass a concrete type instead.

Examples

Create an NSValue containing an i32.

use objc2_foundation::NSValue;

let val = NSValue::new(42i32);

impl NSValue

Getter methods.

pub unsafe fn get<T: 'static + Copy + Encode>(&self) -> T

Retrieve the data contained in the NSValue.

Safety

The type of T must be what the NSValue actually stores, and any safety invariants that the value has must be upheld.

Note that it may be enough, although is not always, to check whether contains_encoding returns true. For example, NonNull<T> have the same encoding as *const T, but NonNull<T> is clearly not safe to return from this function even if you’ve checked the encoding beforehand.

Examples

Store a pointer in NSValue, and retrieve it again afterwards.

use std::ffi::c_void;
use std::ptr;
use objc2_foundation::NSValue;

let val = NSValue::new::<*const c_void>(ptr::null());
// SAFETY: The value was just created with a pointer
let res = unsafe { val.get::<*const c_void>() };
assert!(res.is_null());

pub fn get_range(&self) -> Option<NSRange>

Available on crate feature NSRange only.

pub fn get_point(&self) -> Option<NSPoint>

Available on crate features NSGeometry and objc2-core-foundation only.

pub fn get_size(&self) -> Option<NSSize>

Available on crate features NSGeometry and objc2-core-foundation only.

pub fn get_rect(&self) -> Option<NSRect>

Available on crate features NSGeometry and objc2-core-foundation only.

pub fn encoding(&self) -> Option<&str>

pub fn contains_encoding<T: 'static + Copy + Encode>(&self) -> bool

Methods from Deref<Target = NSObject>

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

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>

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());

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.

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`
    }
}

Trait Implementations

impl AsRef<AnyObject> for NSValue

fn as_ref(&self) -> &AnyObject

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

impl AsRef<NSObject> for NSValue

fn as_ref(&self) -> &NSObject

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

impl AsRef<NSValue> for NSDecimalNumber

Available on crate feature NSDecimalNumber only.

fn as_ref(&self) -> &NSValue

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

impl AsRef<NSValue> for NSNumber

fn as_ref(&self) -> &NSValue

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

impl AsRef<NSValue> for NSValue

fn as_ref(&self) -> &Self

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

impl Borrow<AnyObject> for NSValue

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for NSValue

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl Borrow<NSValue> for NSDecimalNumber

Available on crate feature NSDecimalNumber only.

fn borrow(&self) -> &NSValue

Immutably borrows from an owned value.

impl Borrow<NSValue> for NSNumber

fn borrow(&self) -> &NSValue

Immutably borrows from an owned value.

impl ClassType for NSValue

const NAME: &'static str = "NSValue"

The name of the Objective-C class that this type represents.

type Super = NSObject

The superclass of this class.

type ThreadKind = <<NSValue as ClassType>::Super as ClassType>::ThreadKind

Whether the type can be used from any thread, or from only the main thread.

fn class() -> &'static AnyClass

Get a reference to the Objective-C class that this type represents.

fn as_super(&self) -> &Self::Super

Get an immutable reference to the superclass.

impl CopyingHelper for NSValue

Available on crate feature NSObject only.

type Result = NSValue

The immutable counterpart of the type, or Self if the type has no immutable counterpart.

impl Debug for NSValue

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

Formats the value using the given formatter.

impl Deref for NSValue

type Target = NSObject

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Hash for NSValue

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 Message for NSValue

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSCoding for NSValue

unsafe fn encodeWithCoder(&self, coder: &NSCoder)

where Self: Sized + Message,

Available on crate features NSObject and NSCoder only.

unsafe fn initWithCoder( this: Allocated<Self>, coder: &NSCoder, ) -> Option<Retained<Self>>

where Self: Sized + Message,

Available on crate features NSObject and NSCoder only.

impl NSCopying for NSValue

fn copy(&self) -> Retained<Self::Result>

where Self: Sized + Message + CopyingHelper,

Available on crate feature NSObject only.

Returns a new instance that’s a copy of the receiver.

unsafe fn copyWithZone(&self, zone: *mut NSZone) -> Retained<Self::Result>

where Self: Sized + Message + CopyingHelper,

Available on crate feature NSObject only.

Returns a new instance that’s a copy of the receiver.

impl NSObjectProtocol for NSValue

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) -> usize

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>(&self) -> bool

where T: ClassType, 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) -> usize

where Self: Sized + Message,

The reference count of the object.

impl NSSecureCoding for NSValue

unsafe fn supportsSecureCoding() -> bool

where Self: Sized + ClassType,

Available on crate feature NSObject only.

impl PartialEq for NSValue

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 RefEncode for NSValue

const ENCODING_REF: Encoding = <NSObject as ::objc2::RefEncode>::ENCODING_REF

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

impl ToOwned for NSValue

Available on crate feature NSObject only.

type Owned = Retained<NSValue>

The resulting type after obtaining ownership.

fn to_owned(&self) -> Self::Owned

Creates owned data from borrowed data, usually by cloning.

fn clone_into(&self, target: &mut Self::Owned)

Uses borrowed data to replace owned data, usually by cloning.

impl DowncastTarget for NSValue

impl Eq for NSValue