Struct MEByteSource 

pub struct MEByteSource { /* private fields */ }

Available on crate feature MEFormatReader only.

Provides read access to the data in a media asset file.

The Media Toolbox passes an MEByteSource instance for the media asset’s primary file when initializing an MEFormatReader object. The MEFormatReader may request additional MEByteSources be created for related files in the same directory as the primary file by calling the byteSourceForRelatedFileName method.

See also Apple’s documentation

Implementations

impl MEByteSource

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

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

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

The name of a MEByteSource’s file.

The name of the source file for the MEByteSource.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn contentType(&self) -> Option<Retained<UTType>>

Available on crate feature objc2-uniform-type-identifiers only.

A UTType indicating the format of the MEByteSource’s file.

A UTType indicating the format of the source file for the MEByteSource.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn fileLength(&self) -> i64

The length of the MEByteSource’s file.

The length in bytes of the source file for the MEByteSource, or 0 if that information is not available.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn relatedFileNamesInSameDirectory( &self, ) -> Retained<NSArray<NSString>>

The array of related file names in the MEByteSource’s parent directory.

The array of related files within the MEByteSource’s parent directory that are accessible to the MEByteSource. Only the relative file names are returned, not the paths. If no related files are available, returns an empty array.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn readDataOfLength_fromOffset_toDestination_completionHandler( &self, length: usize, offset: i64, dest: NonNull<c_void>, completion_handler: &DynBlock<dyn Fn(usize, *mut NSError)>, )

Available on crate feature block2 only.

Reads bytes from an MEByteSource asynchronously into a buffer.

Asynchronously reads out the specified number of bytes starting at the indicated offset. Returns the actual number of bytes read out in bytesRead. Read attempts that extend beyond the end of the MEByteSource will succeed if they include at least one valid byte before the end of the MEByteSource.

Parameter length: The number of bytes to read.

Parameter offset: The relative offset in bytes from the beginning of the file from which to start reading.

Parameter dest: The block of memory to hold the data to be read. Must be at least num bytes in length.

Parameter completionHandler: The handler that will be invoked when the method completes. ‘bytesRead’ The actual number of bytes read. ‘error’ An NSError object that will contain error information if the method fails, otherwise nil. Returns MEErrorEndOfStream if no more bytes can be read.

Safety

dest must be a valid pointer.

pub unsafe fn readDataOfLength_fromOffset_completionHandler( &self, length: usize, offset: i64, completion_handler: &DynBlock<dyn Fn(*mut NSData, *mut NSError)>, )

Available on crate feature block2 only.

Reads bytes from an MEByteSource asynchronously into an NSData object.

Asynchronously reads out the specified number of bytes starting at the indicated offset. Returns the actual number of bytes read out in bytesRead. Read attempts that extend beyond the end of the MEByteSource will succeed if they include at least one valid byte before the end of the MEByteSource.

Parameter length: The number of bytes to read.

Parameter offset: The relative offset in bytes from the beginning of the file from which to start reading.

Parameter completionHandler: Completion block called when the method completes. ‘data’ The NSData object holding the data that have been read. The NSData length property will indicate the actual number of bytes read. ‘error’ An NSError object that will contain error information if the method fails, otherwise nil. Returns MEErrorEndOfStream if no more bytes can be read.

pub unsafe fn readDataOfLength_fromOffset_toDestination_bytesRead_error( &self, length: usize, offset: i64, dest: NonNull<c_void>, bytes_read_out: NonNull<usize>, ) -> Result<(), Retained<NSError>>

Reads bytes from an MEByteSource synchronously into a buffer.

Synchronously reads out the specified number of bytes starting at the indicated offset. Returns the actual number of bytes read out in bytesReadOut. Read attempts that extend beyond the end of the MEByteSource will succeed if they include at least one valid byte before the end of the MEByteSource.

Parameter length: The number of bytes to read.

Parameter offset: The relative offset in bytes from the beginning of the file from which to start reading.

Parameter dest: The block of memory to hold the data to be read. Must be at least num bytes in length.

Parameter bytesReadOut: The actual number of bytes read.

Parameter error: Reports any errors. Returns MEErrorEndOfStream if no more bytes can be read.

Returns: Returns YES if successful, NO if an error occured.

Safety

• dest must be a valid pointer.
• bytes_read_out must be a valid pointer.

pub unsafe fn availableLengthAtOffset(&self, offset: i64) -> i64

Returns the number of available bytes from the offset within the MEByteSource.

Returns the number of available bytes at the time of the query. This value could change over time. Attempting to read past this value may cause slow I/O.

Parameter offset: The offset in bytes from the beginning of the MEByteSource.

Returns: Returns the number of available bytes from the offset, or 0 if that information is not available.

pub unsafe fn byteSourceForRelatedFileName_error( &self, file_name: &NSString, ) -> Result<Retained<MEByteSource>, Retained<NSError>>

Requests creation of a new MEByteSource for a related file.

Requests creation of a new MEByteSource for a file related to the receiving MEByteSource. The scope of fileName that may be opened is restricted. Only files in the same directory as the receiver MEByteSource may be accessed, and the file extension must match one of the extensions listed in the format reader bundle plist.

Parameter fileName: The relative file name in the receiver MEByteSource’s parent directory.

Parameter errorOut: Reports any errors. Returns MEErrorPermissionDenied if the file cannot be accessed or is prohibited.

Returns: Returns nil if fileName refers to a file that cannot be accessed or is prohibited, or if an error occured. The returned MEByteSource is autoreleased.

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 MEByteSource

fn as_ref(&self) -> &AnyObject

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

impl AsRef<MEByteSource> for MEByteSource

fn as_ref(&self) -> &Self

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

impl AsRef<NSObject> for MEByteSource

fn as_ref(&self) -> &NSObject

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

impl Borrow<AnyObject> for MEByteSource

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for MEByteSource

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for MEByteSource

const NAME: &'static str = "MEByteSource"

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

type Super = NSObject

The superclass of this class.

type ThreadKind = <<MEByteSource 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 Debug for MEByteSource

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

Formats the value using the given formatter.

impl Deref for MEByteSource

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for MEByteSource

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 MEByteSource

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for MEByteSource

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 MEByteSource

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 MEByteSource

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

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

impl DowncastTarget for MEByteSource

impl Eq for MEByteSource

impl Send for MEByteSource

impl Sync for MEByteSource