Struct XCTPerformanceMeasurement

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pub struct XCTPerformanceMeasurement { /* private fields */ }

Expand description

Contains the data acquired from a single metric being measured for an individual iteration.

Implementations§

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impl XCTPerformanceMeasurement

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pub fn identifier(&self) -> Retained<NSString>

A unique identifier for this measurement such as “com.apple.XCTPerformanceMetric_WallClockTime”.

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pub fn displayName(&self) -> Retained<NSString>

The human-readable name for this measurement, such as “Wall Clock Time”.

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pub fn value(&self) -> Retained<NSMeasurement>

The value of the measurement.

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pub fn doubleValue(&self) -> c_double

The double value of the measurement.

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pub fn unitSymbol(&self) -> Retained<NSString>

A string describing the unit the value is in.

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pub fn polarity(&self) -> XCTPerformanceMeasurementPolarity

An enum value representing in which direction measurements should be compared against their baselines.

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pub unsafe fn initWithIdentifier_displayName_value( this: Allocated<Self>, identifier: &NSString, display_name: &NSString, value: &NSMeasurement, ) -> Retained<Self>

Initializes an object which encapsulates the measurement for a metric during a single iteration.

Parameter identifier: A unique identifier for this measurement such as “com.apple.XCTPerformanceMetric_WallClockTime”.

Parameter displayName: A human-readable name for this measurement, such as “Wall Clock Time”.

Parameter value: The value of the measurement.

§Safety

value generic should be bound by AsRef<NSUnit>.

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pub fn initWithIdentifier_displayName_doubleValue_unitSymbol( this: Allocated<Self>, identifier: &NSString, display_name: &NSString, double_value: c_double, unit_symbol: &NSString, ) -> Retained<Self>

Initializes an object which encapsulates the measurement for a metric during a single iteration.

Parameter identifier: A unique identifier for this measurement such as “com.apple.XCTPerformanceMetric_WallClockTime”.

Parameter displayName: A human-readable name for this measurement, such as “Wall Clock Time”.

Parameter doubleValue: The double value of the measurement.

Parameter unitSymbol: A string describing the unit the value is in.

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pub unsafe fn initWithIdentifier_displayName_value_polarity( this: Allocated<Self>, identifier: &NSString, display_name: &NSString, value: &NSMeasurement, polarity: XCTPerformanceMeasurementPolarity, ) -> Retained<Self>

Initializes an object which encapsulates the measurement for a metric during a single iteration.

Parameter identifier: A unique identifier for this measurement such as “com.apple.XCTPerformanceMetric_WallClockTime”.

Parameter displayName: A human-readable name for this measurement, such as “Wall Clock Time”.

Parameter value: The value of the measurement.

Parameter polarity: An enum value representing in which direction measurements should be compared against their baselines.

§Safety

value generic should be bound by AsRef<NSUnit>.

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pub fn initWithIdentifier_displayName_doubleValue_unitSymbol_polarity( this: Allocated<Self>, identifier: &NSString, display_name: &NSString, double_value: c_double, unit_symbol: &NSString, polarity: XCTPerformanceMeasurementPolarity, ) -> Retained<Self>

Initializes an object which encapsulates the measurement for a metric during a single iteration.

Parameter identifier: A unique identifier for this measurement such as “com.apple.XCTPerformanceMetric_WallClockTime”.

Parameter displayName: A human-readable name for this measurement, such as “Wall Clock Time”.

Parameter doubleValue: The double value of the measurement.

Parameter unitSymbol: A string describing the unit the value is in.

Parameter polarity: An enum value representing in which direction measurements should be compared against their baselines.

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

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pub 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`
    }
}