Struct SHSession 

pub struct SHSession { /* private fields */ }

Available on crate feature SHSession only.

An object that matches a specific audio recording when a segment of that recording is part of captured sound in the Shazam catalog or your custom catalog.

Prepare to make matches by:

• Creating a session for the catalog that contains the reference signatures
• Adding your delegate that receives the match results

Search for a match in one of two ways:

• Generate a signature for the captured audio and call match(_:)
• Call matchStreamingBuffer(_:at:) with a streaming audio buffer, and ShazamKit generates the signature for you

Searching the catalog is asynchronous. The session calls your delegate methods with the result.

Matching songs in Shazam music requires enabling your app to access the catalog. For more information on enabling your app, see Enable ShazamKit for an App ID.

The code below shows searching for a match in the Shazam catalog using an existing audio buffer:

// Set up the session.
let session = SHSession()

// Create a signature from the captured audio buffer.
let signatureGenerator = SHSignatureGenerator()
try signatureGenerator.append(buffer, at: audioTime)
let signature = signatureGenerator.signature()

// Check for a match.
let result = await session.result(from: signature)

// Use the result.
switch result {
case .match(let match):
// Match found.
case .noMatch(let signature):
// No match found.
case .error(let error, let signature):
// An error occurred.
}

See also Apple’s documentation

Implementations

impl SHSession

pub unsafe fn catalog(&self) -> Retained<SHCatalog>

Available on crate feature SHCatalog only.

The catalog object containing the reference signatures and their associated metadata that the session uses to perform matches.

pub unsafe fn delegate( &self, ) -> Option<Retained<ProtocolObject<dyn SHSessionDelegate>>>

The object that the session calls with the result of a match request.

pub unsafe fn setDelegate( &self, delegate: Option<&ProtocolObject<dyn SHSessionDelegate>>, )

Setter for delegate.

This is a weak property.

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

Creates a new session object for matching songs in the Shazam Music catalog.

pub unsafe fn initWithCatalog( this: Allocated<Self>, catalog: &SHCatalog, ) -> Retained<Self>

Available on crate feature SHCatalog only.

Creates a new session object for matching audio in a custom catalog.

• Parameters:
• catalog: The catalog that contains the reference audio signatures and their associated metadata.

pub unsafe fn matchStreamingBuffer_atTime( &self, buffer: &AVAudioPCMBuffer, time: Option<&AVAudioTime>, )

Available on crate feature objc2-avf-audio only.

Converts the audio in the buffer to a signature, and searches the reference signatures in the session catalog.

This method continues to generate signatures and perform searches until the audio in the buffer stops, which may result in multiple calls to the SHSession/delegate.

The audio buffer must be in one of the supported formats. For the list of the supported audio formats, see SHSignatureGenerator/append(_:at:).

To use the microphone as input for the buffer, see .

Note: You must use the audio format of the first call to this method in the current session in all subsequent calls for the session.

• Parameters:
• buffer: An audio buffer.
• time: The start time of the audio to use for generating the signatures.

pub unsafe fn matchSignature(&self, signature: &SHSignature)

Available on crate feature SHSignature only.

Searches for the query signature in the reference signatures that the session catalog contains.

• Parameters:
• signature: The signature for searching the catalog of reference signatures.

impl SHSession

Methods declared on superclass NSObject.

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

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 SHSession

fn as_ref(&self) -> &AnyObject

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

impl AsRef<NSObject> for SHSession

fn as_ref(&self) -> &NSObject

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

impl AsRef<SHSession> for SHSession

fn as_ref(&self) -> &Self

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

impl Borrow<AnyObject> for SHSession

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for SHSession

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for SHSession

const NAME: &'static str = "SHSession"

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

type Super = NSObject

The superclass of this class.

type ThreadKind = <<SHSession 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 SHSession

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

Formats the value using the given formatter.

impl Deref for SHSession

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for SHSession

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 SHSession

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for SHSession

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 SHSession

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 SHSession

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

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

impl DowncastTarget for SHSession

impl Eq for SHSession