Struct AVMetadataItem 

pub struct AVMetadataItem { /* private fields */ }

Available on crate feature AVMetadataItem only.

Apple’s documentation

Implementations

impl AVMetadataItem

pub unsafe fn identifier(&self) -> Option<Retained<AVMetadataIdentifier>>

Available on crate feature AVMetadataIdentifiers only.

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

pub unsafe fn locale(&self) -> Option<Retained<NSLocale>>

pub unsafe fn time(&self) -> CMTime

Available on crate feature objc2-core-media only.

pub unsafe fn duration(&self) -> CMTime

Available on crate feature objc2-core-media only.

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

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

pub unsafe fn extraAttributes( &self, ) -> Option<Retained<NSDictionary<AVMetadataExtraAttributeKey, AnyObject>>>

Available on crate feature AVMetadataFormat only.

impl AVMetadataItem

Methods declared on superclass NSObject.

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

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

impl AVMetadataItem

AVMetadataItemDateRepresentation.

pub unsafe fn startDate(&self) -> Option<Retained<NSDate>>

impl AVMetadataItem

AVMetadataItemTypeCoercion.

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

pub unsafe fn numberValue(&self) -> Option<Retained<NSNumber>>

pub unsafe fn dateValue(&self) -> Option<Retained<NSDate>>

pub unsafe fn dataValue(&self) -> Option<Retained<NSData>>

impl AVMetadataItem

AVAsynchronousKeyValueLoading.

pub unsafe fn loadValuesAsynchronouslyForKeys_completionHandler( &self, keys: &NSArray<NSString>, handler: Option<&DynBlock<dyn Fn()>>, )

Available on crate feature block2 only.

Safety

handler block must be sendable.

impl AVMetadataItem

AVMetadataItemArrayFiltering.

pub unsafe fn metadataItemsFromArray_filteredAndSortedAccordingToPreferredLanguages( metadata_items: &NSArray<AVMetadataItem>, preferred_languages: &NSArray<NSString>, ) -> Retained<NSArray<AVMetadataItem>>

Filters an array of AVMetadataItems according to whether their locales match any language identifier in the specified array of preferred languages. The returned array is sorted according to the order of preference of the language each matches.

Parameter metadataItems: An array of AVMetadataItems to be filtered and sorted.

Parameter preferredLanguages: An array of language identifiers in order of preference, each of which is an IETF BCP 47 (RFC 4646) language identifier. If your goal is to provide the best match for the end user’s preferred languages without consideration of your app’s available localizations, pass [NSLocale preferredLanguages] as the value of preferredLanguages. However, if you want to filter the available choices in order to obtain the best match among the localizations that are available for your app, pass [NSBundle preferredLocalizationsFromArray:[[NSBundle mainBundle] localizations] forPreferences:[NSLocale preferredLanguages]] instead. The latter choice is normally more appropriate for strings intended for display as part of the app’s UI.

Returns: An instance of NSArray containing metadata items of the specified NSArray that match a preferred language, sorted according to the order of preference of the language each matches.

pub unsafe fn metadataItemsFromArray_filteredByIdentifier( metadata_items: &NSArray<AVMetadataItem>, identifier: &AVMetadataIdentifier, ) -> Retained<NSArray<AVMetadataItem>>

Available on crate feature AVMetadataIdentifiers only.

Filters an array of AVMetadataItems according to identifier.

Parameter metadataItems: An array of AVMetadataItems to be filtered by identifier.

Parameter identifier: The identifier that must be matched for a metadata item to be copied to the output array. Items are considered a match not only when their identifiers are equal to the specified identifier, and also when their identifiers conform to the specified identifier.

Returns: An instance of NSArray containing the metadata items of the target NSArray that match the specified identifier.

pub unsafe fn metadataItemsFromArray_filteredByMetadataItemFilter( metadata_items: &NSArray<AVMetadataItem>, metadata_item_filter: &AVMetadataItemFilter, ) -> Retained<NSArray<AVMetadataItem>>

Filters an array of AVMetadataItems using the supplied AVMetadataItemFilter.

Parameter metadataItems: An array of AVMetadataItems to be filtered.

Parameter metadataItemFilter: The AVMetadataItemFilter object for filtering the metadataItems.

Returns: An instance of NSArray containing the metadata items of the target NSArray that have not been removed by metadataItemFilter.

impl AVMetadataItem

AVMetadataItemKeyAndKeyspace.

pub unsafe fn identifierForKey_keySpace( key: &AnyObject, key_space: &AVMetadataKeySpace, ) -> Option<Retained<AVMetadataIdentifier>>

Available on crate features AVMetadataFormat and AVMetadataIdentifiers only.

Provides the metadata identifier that’s equivalent to a key and keySpace.

Parameter key: The metadata key.

Parameter keySpace: The metadata keySpace.

Returns: A metadata identifier equivalent to the given key and keySpace, or nil if no identifier can be constructed from the given key and keySpace.

Metadata keys that are not instances of NSString, NSNumber, or NSData cannot be converted to metadata identifiers; they also cannot be written to media resources via AVAssetExportSession or AVAssetWriter. Metadata item keySpaces must be a string of one to four printable ASCII characters.

For custom identifiers, the keySpace AVMetadataKeySpaceQuickTimeMetadata is recommended. This keySpace defines its key values to be expressed as reverse-DNS strings, which allows third parties to define their own keys in a well established way that avoids collisions.

Safety

key should be of the correct type.

pub unsafe fn keySpaceForIdentifier( identifier: &AVMetadataIdentifier, ) -> Option<Retained<AVMetadataKeySpace>>

Available on crate features AVMetadataFormat and AVMetadataIdentifiers only.

pub unsafe fn keyForIdentifier( identifier: &AVMetadataIdentifier, ) -> Option<Retained<AnyObject>>

Available on crate feature AVMetadataIdentifiers only.

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

pub unsafe fn commonKey(&self) -> Option<Retained<AVMetadataKey>>

Available on crate feature AVMetadataFormat only.

pub unsafe fn keySpace(&self) -> Option<Retained<AVMetadataKeySpace>>

Available on crate feature AVMetadataFormat only.

impl AVMetadataItem

AVMetadataItemLazyValueLoading.

pub unsafe fn metadataItemWithPropertiesOfMetadataItem_valueLoadingHandler( metadata_item: &AVMetadataItem, handler: &DynBlock<dyn Fn(NonNull<AVMetadataItemValueRequest>)>, ) -> Retained<AVMetadataItem>

Available on crate feature block2 only.

Creates an instance of AVMutableMetadataItem with a value that you do not wish to load unless required, e.g. a large image value that needn’t be loaded into memory until another module wants to display it.

Parameter metadataItem: An instance of AVMetadataItem with the identifier, extendedLanguageTag, and other property values that you want the newly created instance of AVMetadataItem to share. The value of metadataItem is ignored.

Parameter handler: A block that loads the value of the metadata item.

Returns: An instance of AVMetadataItem.

This method is intended for the creation of metadata items for optional display purposes, when there is no immediate need to load specific metadata values. For example, see the interface for navigation markers as consumed by AVPlayerViewController. It’s not intended for the creation of metadata items with values that are required immediately, such as metadata items that are provided for impending serialization operations (e.g. via -[AVAssetExportSession setMetadata:] and other similar methods defined on AVAssetWriter and AVAssetWriterInput). When -loadValuesAsynchronouslyForKeys:completionHandler: is invoked on an AVMetadataItem created via +metadataItemWithPropertiesOfMetadataItem:valueLoadingHandler: and “ value“ is among the keys for which loading is requested, the block you provide as the value loading handler will be executed on an arbitrary dispatch queue, off the main thread. The handler can perform I/O and other necessary operations to obtain the value. If loading of the value succeeds, provide the value by invoking -[AVMetadataItemValueRequest respondWithValue:]. If loading of the value fails, provide an instance of NSError that describes the failure by invoking -[AVMetadataItemValueRequest respondWithError:].

Safety

handler block must be sendable.

impl AVMetadataItem

AVMetadataItemArrayFilteringDeprecable.

pub unsafe fn metadataItemsFromArray_withLocale( metadata_items: &NSArray<AVMetadataItem>, locale: &NSLocale, ) -> Retained<NSArray<AVMetadataItem>>

Instead, use metadataItemsFromArray:filteredAndSortedAccordingToPreferredLanguages:.

pub unsafe fn metadataItemsFromArray_withKey_keySpace( metadata_items: &NSArray<AVMetadataItem>, key: Option<&AnyObject>, key_space: Option<&AVMetadataKeySpace>, ) -> Retained<NSArray<AVMetadataItem>>

Available on crate feature AVMetadataFormat only.

Instead, use metadataItemsFromArray:filteredByIdentifier:.

Safety

key should be of the correct type.

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 AVAsynchronousKeyValueLoading for AVMetadataItem

unsafe fn loadValuesAsynchronouslyForKeys_completionHandler( &self, keys: &NSArray<NSString>, handler: Option<&DynBlock<dyn Fn()>>, )

where Self: Sized + Message,

Available on crate features AVAsynchronousKeyValueLoading and block2 only.

Directs the target to load the values of any of the specified keys that are not already loaded.

impl AsRef<AVMetadataItem> for AVMetadataItem

fn as_ref(&self) -> &Self

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

impl AsRef<AVMetadataItem> for AVMutableMetadataItem

fn as_ref(&self) -> &AVMetadataItem

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

impl AsRef<AnyObject> for AVMetadataItem

fn as_ref(&self) -> &AnyObject

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

impl AsRef<NSObject> for AVMetadataItem

fn as_ref(&self) -> &NSObject

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

impl Borrow<AVMetadataItem> for AVMutableMetadataItem

fn borrow(&self) -> &AVMetadataItem

Immutably borrows from an owned value.

impl Borrow<AnyObject> for AVMetadataItem

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for AVMetadataItem

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for AVMetadataItem

const NAME: &'static str = "AVMetadataItem"

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

type Super = NSObject

The superclass of this class.

type ThreadKind = <<AVMetadataItem 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 AVMetadataItem

type Result = AVMetadataItem

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

impl Debug for AVMetadataItem

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

Formats the value using the given formatter.

impl Deref for AVMetadataItem

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for AVMetadataItem

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 AVMetadataItem

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

where Self: Sized,

Increment the reference count of the receiver.

impl MutableCopyingHelper for AVMetadataItem

type Result = AVMutableMetadataItem

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

impl NSCopying for AVMetadataItem

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

where Self: Sized + Message + CopyingHelper,

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,

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

impl NSMutableCopying for AVMetadataItem

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

where Self: Sized + Message + MutableCopyingHelper,

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

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

where Self: Sized + Message + MutableCopyingHelper,

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

impl NSObjectProtocol for AVMetadataItem

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 PartialEq for AVMetadataItem

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 AVMetadataItem

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

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

impl DowncastTarget for AVMetadataItem

impl Eq for AVMetadataItem