Struct IOUSBHostCIControllerStateMachine

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pub struct IOUSBHostCIControllerStateMachine { /* private fields */ }

Available on crate feature IOUSBHostCIControllerStateMachine only.

Expand description

The object representing the state of a user-mode USB host controller

This class assists with tracking internal state transitions of a user-mode USB host controller, and parses IOUSBHostCIMessage command structures to update state and generate properly formatted command responses.

IOUSBHostCIControllerStateMachine does not provide any concurrency protection, the client is responsible for necessary serialization.

Implementations§

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impl IOUSBHostCIControllerStateMachine

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

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pub unsafe fn initWithInterface_error( this: Allocated<Self>, interface: &IOUSBHostControllerInterface, ) -> Result<Retained<Self>, Retained<NSError>>

Available on crate feature IOUSBHostControllerInterface only.

Initializes an IOUSBHostCIControllerStateMachine object

The IOUSBHostCIControllerStateMachine defaults to the IOUSBHostCIControllerStateOff state.

Parameter interface: IOUSBHostControllerInterface which will be used to send command responses.

Returns: IOUSBHostCIControllerStateMachine instance, to be released by the caller.

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pub unsafe fn inspectCommand_error( &self, command: NonNull<IOUSBHostCIMessage>, ) -> Result<(), Retained<NSError>>

Available on crate feature IOUSBHostControllerInterfaceDefinitions only.

Inspect an IOUSBHostCIMessage command

The IOUSBHostCIMessage command is inspected to determine if it is handled by the state machine, and is appropriate for the current state.

Parameter command: IOUSBHostCIMessage command structure received from the kernel driver.

Returns: BOOL YES if the command is targeting a controller, and can be handled in the current state BOOL NO if the command does not target a controller, or cannot be handled in the current state

§Safety

command must be a valid pointer.

Source

pub unsafe fn respondToCommand_status_error( &self, command: NonNull<IOUSBHostCIMessage>, status: IOUSBHostCIMessageStatus, ) -> Result<(), Retained<NSError>>

Available on crate feature IOUSBHostControllerInterfaceDefinitions only.

Advance the state machine and respond to an IOUSBHostCIMessage command

If the command passes inspectCommand and the client indicates the command was processed successfully, the state machine is advanced, and a properly formatted command response message is sent to the kernel driver. If the client indicates the command was not processed successfully, the state machine is not advanced but a properly formatted command response message is sent to the kernel driver.

Parameter command: IOUSBHostCIMessage command structure received from the kernel driver.

Parameter status: IOUSBHostCIMessageStatus reported by the user-mode USB host controller implementation for the command response.

Returns: BOOL YES if the command response was sent to the kernel driver BOOL NO if the command response was not sent to the kernel driver

§Safety

command must be a valid pointer.

Source

pub unsafe fn respondToCommand_status_frame_timestamp_error( &self, command: NonNull<IOUSBHostCIMessage>, status: IOUSBHostCIMessageStatus, frame: u64, timestamp: u64, ) -> Result<(), Retained<NSError>>

Available on crate feature IOUSBHostControllerInterfaceDefinitions only.

Advance the state machine and respond to an IOUSBHostCIMessageTypeControllerFrameNumber command

If the command passes inspectCommand and the client indicates the command was processed successfully, enqueueUpdatedFrame:timestamp:error is called with the supplied parameters, and a properly formatted command response message is sent to the kernel driver. If the client indicates the command was not processed successfully, enqueueUpdatedFrame:timestamp:error is not called but a properly formatted command response message is sent to the kernel driver.

Parameter command: IOUSBHostCIMessage command structure received from the kernel driver. The Type field must be IOUSBHostCIMessageTypeControllerFrameNumber

Parameter status: IOUSBHostCIMessageStatus reported by the user-mode USB host controller implementation for the command response.

Parameter frame: uint64_t containing the number of 1ms frames that have elapsed since the controller began counting frames

Parameter timestamp: uint64_t containing the mach_absolute_time() correlated to the beginning of the frameNumber

Returns: BOOL YES if the command response was sent to the kernel driver BOOL NO if the command response was not sent to the kernel driver

§Safety

command must be a valid pointer.

Source

pub unsafe fn enqueueUpdatedFrame_timestamp_error( &self, frame: u64, timestamp: u64, ) -> Result<(), Retained<NSError>>

Enqueue frame and timestamp messages for delivery to the kernel driver

If the controller interface is in the IOUSBHostCIControllerStateActive state, messages with the type IOUSBHostCIMessageTypeFrameNumberUpdate and IOUSBHostCIMessageTypeFrameTimestampUpdate will be generated using the provided inputs, and enqueued for delivery to the kernel driver. The frame and timestamp information provided effectively measure the duration of the controller’s 1ms frame in terms of system time. A 1% frame duration variation is permitted. A larger frame duration variation will result in a IOUSBHostCIExceptionTypeFrameUpdateError.

Parameter frame: uint64_t containing the number of 1ms frames that have elapsed since the controller began counting frames

Parameter timestamp: uint64_t containing the mach_absolute_time() correlated to the beginning of the frameNumber

Returns: BOOL YES if the messages were enqueued for delivery to the kernel. BOOL NO if the messages were not enqueued for delivery to the kernel.

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pub unsafe fn controllerState(&self) -> IOUSBHostCIControllerState

Available on crate feature IOUSBHostControllerInterfaceDefinitions only.

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pub unsafe fn controllerInterface( &self, ) -> Retained<IOUSBHostControllerInterface>

Available on crate feature IOUSBHostControllerInterface only.

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impl IOUSBHostCIControllerStateMachine

Methods declared on superclass NSObject.

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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.

Source

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`
    }
}