Struct CKSyncEngineState 

pub struct CKSyncEngineState { /* private fields */ }

Available on crate feature CKSyncEngineState only.

An object that tracks some state required for proper and efficient operation of CKSyncEngine-5sie5.

CKSyncEngine-5sie5 needs to track several things in order to properly sync. For example, it needs to remember the last server change tokens for your database and zones. It also needs to keep track of things like the last known user record ID and other various pieces of state.

A lot of this state is hidden internally, but some of it you can control.

Pending changes

One of the main things you can control is the list of pending changes to send to the server. You can control these by calling functions like addPendingDatabaseChanges: and addPendingRecordZoneChanges:. When you add new pending changes, the sync engine will automatically schedule a task to sync with the server.

State serialization

CKSyncEngine-5sie5 will occasionally update its state in the background. When it updates its state, your delegate will receive a CKSyncEngineStateUpdateEvent.

This event will contain a CKSyncEngineStateSerialization, which you should persist locally. The next time your process launches, you initialize your sync engine with the last state serialization you received.

See also Apple’s documentation

Implementations

impl CKSyncEngineState

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

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

pub unsafe fn pendingRecordZoneChanges( &self, ) -> Retained<NSArray<CKSyncEnginePendingRecordZoneChange>>

A list of record changes that need to be sent to the server.

CKSyncEngine-5sie5 provides the convenience of tracking your pending record zone changes. When the user makes some changes that need to be sent to the server, you can track them in this list. Then, you can use this list when creating your next CKSyncEngineRecordZoneChangeBatch in your CKSyncEngineDelegate-1q7g8.

The sync engine will ensure consistency and deduplicate these pending changes under the hood. For example, if you add a pending save for record A, then record B, then record A again, this will result in a list of [saveRecordA, saveRecordB]. Similarly, if you add a pending save for record A, then add a pending delete for the same record A, this will result in a single pending change of [deleteRecordA].

The sync engine will manage this list while it sends changes to the server. For example, when it successfully saves a record, it will remove that change from this list. If it fails to send a change due to some retryable error (e.g. a network failure), it will keep that change in this list.

If you’d prefer to track pending changes yourself, you can use CKSyncEngine/State/hasPendingUntrackedChanges instead.

pub unsafe fn pendingDatabaseChanges( &self, ) -> Retained<NSArray<CKSyncEnginePendingDatabaseChange>>

A list of database changes that need to be sent to the server, similar to pendingRecordZoneChanges.

pub unsafe fn hasPendingUntrackedChanges(&self) -> bool

This represents whether or not you have pending changes to send to the server that aren’t tracked in CKSyncEngine/State/pendingRecordZoneChanges. This is useful if you want to track pending changes in your own local database instead of the sync engine state.

When this property is set, the sync engine will automatically schedule a sync. When the sync task runs, it will ask your delegate for pending changes in CKSyncEngineDelegate/nextRecordZoneChangeBatch(_:syncEngine:).

pub unsafe fn setHasPendingUntrackedChanges( &self, has_pending_untracked_changes: bool, )

Setter for hasPendingUntrackedChanges.

pub unsafe fn zoneIDsWithUnfetchedServerChanges( &self, ) -> Retained<NSArray<CKRecordZoneID>>

Available on crate feature CKRecordZoneID only.

The list of zone IDs that have new changes to fetch from the server. CKSyncEngine-5sie5 keeps track of these zones and will update this list as it receives new information.

pub unsafe fn addPendingRecordZoneChanges( &self, changes: &NSArray<CKSyncEnginePendingRecordZoneChange>, )

Adds to the list of pending record zone changes.

When you add a new pending change, the sync engine will automatically schedule a sync task.

The sync engine will ensure consistency and deduplicate these changes under the hood.

pub unsafe fn removePendingRecordZoneChanges( &self, changes: &NSArray<CKSyncEnginePendingRecordZoneChange>, )

Removes from the list of pending record zone changes.

pub unsafe fn addPendingDatabaseChanges( &self, changes: &NSArray<CKSyncEnginePendingDatabaseChange>, )

Adds to the list of pending database changes.

When you add a new pending change, the sync engine will automatically schedule a sync task.

The sync engine will ensure consistency and deduplicate these changes under the hood.

pub unsafe fn removePendingDatabaseChanges( &self, changes: &NSArray<CKSyncEnginePendingDatabaseChange>, )

Removes from the list of pending database changes.

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 CKSyncEngineState

fn as_ref(&self) -> &AnyObject

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

impl AsRef<CKSyncEngineState> for CKSyncEngineState

fn as_ref(&self) -> &Self

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

impl AsRef<NSObject> for CKSyncEngineState

fn as_ref(&self) -> &NSObject

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

impl Borrow<AnyObject> for CKSyncEngineState

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for CKSyncEngineState

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for CKSyncEngineState

const NAME: &'static str = "CKSyncEngineState"

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

type Super = NSObject

The superclass of this class.

type ThreadKind = <<CKSyncEngineState 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 CKSyncEngineState

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

Formats the value using the given formatter.

impl Deref for CKSyncEngineState

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for CKSyncEngineState

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 CKSyncEngineState

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for CKSyncEngineState

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 CKSyncEngineState

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 CKSyncEngineState

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

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

impl DowncastTarget for CKSyncEngineState

impl Eq for CKSyncEngineState

impl Send for CKSyncEngineState

impl Sync for CKSyncEngineState