Struct NSCachedURLResponse

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

Available on crate feature NSURLCache only.

Expand description

NSCachedURLResponse is a class whose objects functions as a wrapper for objects that are stored in the framework’s caching system. It is used to maintain characteristics and attributes of a cached object.

Implementations§

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impl NSCachedURLResponse

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pub unsafe fn initWithResponse_data( this: Allocated<Self>, response: &NSURLResponse, data: &NSData, ) -> Retained<Self>

Available on crate features NSData and NSURLResponse only.

Initializes an NSCachedURLResponse with the given response and data.

A default NSURLCacheStoragePolicy is used for NSCachedURLResponse objects initialized with this method: NSURLCacheStorageAllowed.

Parameter response: a NSURLResponse object.

Parameter data: an NSData object representing the URL content corresponding to the given response.

Returns: an initialized NSCachedURLResponse.

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pub unsafe fn initWithResponse_data_userInfo_storagePolicy( this: Allocated<Self>, response: &NSURLResponse, data: &NSData, user_info: Option<&NSDictionary>, storage_policy: NSURLCacheStoragePolicy, ) -> Retained<Self>

Available on crate features NSData and NSDictionary and NSURLResponse only.

Initializes an NSCachedURLResponse with the given response, data, user-info dictionary, and storage policy.

Parameter response: a NSURLResponse object.

Parameter data: an NSData object representing the URL content corresponding to the given response.

Parameter userInfo: a dictionary user-specified information to be stored with the NSCachedURLResponse.

Parameter storagePolicy: an NSURLCacheStoragePolicy constant.

Returns: an initialized NSCachedURLResponse.

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pub unsafe fn response(&self) -> Retained<NSURLResponse>

Available on crate feature NSURLResponse only.

Returns the response wrapped by this instance.

Returns: The response wrapped by this instance.

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

Available on crate feature NSData only.

Returns the data of the receiver.

Returns: The data of the receiver.

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pub unsafe fn userInfo(&self) -> Option<Retained<NSDictionary>>

Available on crate feature NSDictionary only.

Returns the userInfo dictionary of the receiver.

Returns: The userInfo dictionary of the receiver.

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pub unsafe fn storagePolicy(&self) -> NSURLCacheStoragePolicy

Returns the NSURLCacheStoragePolicy constant of the receiver.

Returns: The NSURLCacheStoragePolicy constant of the receiver.

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impl NSCachedURLResponse

Methods declared on superclass NSObject.

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

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

Methods from Deref<Target = NSObject>§

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

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>§

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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());

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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.

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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`
    }
}