Struct DisplayOwnership 

pub struct DisplayOwnership { /* private fields */ }

A handler that turns the input pipeline off or on based on whether the Scenic owns the display.

This allows us to turn off keyboard processing when the user switches away from the product (e.g. terminal) into virtual console.

See the README.md file in this crate for details.

Safety and Concurrency

This struct uses RefCell to manage internal state. While DisplayOwnership logic is split between multiple tasks (handle_ownership_change and handle_unhandled_input_event), safety is maintained because:

1. The pipeline runs on a single-threaded LocalExecutor.
2. Borrows of RefCells (like ownership and key_state) are never held across await points.

If asynchronous calls are added to critical sections in the future, ensure that all borrows are dropped before the await.

Implementations

impl DisplayOwnership

pub fn new( display_ownership_event: impl AsHandleRef + 'static, input_handlers_node: &Node, ) -> Rc<Self>

Creates a new handler that watches display_ownership_event for events.

The display_ownership_event is assumed to be an [Event] obtained from fuchsia.ui.composition.internal.DisplayOwnership/GetEvent. There isn’t really a way for this code to know here whether this is true or not, so implementor beware.

pub async fn handle_ownership_change( self: &Rc<Self>, output: UnboundedSender<InputEvent>, ) -> Result<()>

Watches for display ownership changes and sends cancel/sync events.

NOTE: RefCell safety relies on the single-threaded nature of the executor. No borrows of ownership or key_state must be held across the await below to avoid panics if handle_unhandled_input_event runs while this task is suspended.

Trait Implementations

impl UnhandledInputHandler for DisplayOwnership

fn handle_unhandled_input_event<'async_trait>( self: Rc<Self>, unhandled_input_event: UnhandledInputEvent, ) -> Pin<Box<dyn Future<Output = Vec<InputEvent>> + 'async_trait>>

where Self: 'async_trait,

Returns a vector of InputEvents to propagate to the next InputHandler.

fn set_handler_healthy(self: Rc<Self>)

fn set_handler_unhealthy(self: Rc<Self>, msg: &str)

fn get_name(&self) -> &'static str

fn interest(&self) -> Vec<InputEventType>

Returns the types of input events this handler is interested in.