Struct InputOwnershipSynchronousProxy

Source

pub struct InputOwnershipSynchronousProxy { /* private fields */ }

Implementations§

Source §

pub fn wait_for_event( &self, deadline: MonotonicInstant, ) -> Result<InputOwnershipEvent, Error>

Waits until an event arrives and returns it. It is safe for other threads to make concurrent requests while waiting for an event.

Source

pub fn get_event( &self, target: InputOwnershipTarget, ___deadline: MonotonicInstant, ) -> Result<InputOwnershipGetEventResult, Error>

Gets a duplicate handle to the shared kernel ownership_event whose orthogonal signals inform clients and the system pipeline when direct driver input access (fuchsia.input.report.Service) is granted or revoked:

Virtcon (target = virtcon: {}): owns input iff InputOwnershipSignal.DISPLAY_UNOWNED is asserted.
Starnix (target = view_ref): owns direct input iff both InputOwnershipSignal.DISPLAY_PLATFORM_OWNED and InputOwnershipSignal.INPUT_CLIENT_OWNED are asserted.
SceneManager (target = platform: {}): owns platform pipeline input iff both InputOwnershipSignal.DISPLAY_PLATFORM_OWNED and InputOwnershipSignal.INPUT_PLATFORM_OWNED are asserted (pauses whenever DISPLAY_UNOWNED or INPUT_CLIENT_OWNED is asserted).

Requesting direct input ownership:

Calling GetEvent with target = view_ref is also how a view requests direct input ownership; there is no separate request method. GetEvent supports pre-registering a valid ViewRef before the view is created or attached to the ViewTree. On success, the server registers the ViewRef as the system-wide direct input client, immediately evaluates it against the latest ViewTree snapshot if one exists, and continues evaluating it against the single-view + full-screen criteria on every subsequent ViewTree update. INPUT_CLIENT_OWNED is asserted only while the registered view meets those criteria; otherwise INPUT_PLATFORM_OWNED is asserted.

Registration is singleton and last-writer-wins: a successful call with a different ViewRef replaces any previously registered view. This mechanism is intended for a single trusted client replacing its own view rather than independent concurrent components: because every GetEvent call returns a handle to the same shared kernel ownership_event, replacing the registered ViewRef does not silence earlier callers’ handles when their view is unlinked or destroyed and the new view goes fullscreen.
If the ViewTree contains more than one view or overlay competing with the registered view, the criteria are not met and ownership falls back to the platform. Thus, when multiple views request direct input while coexisting in the ViewTree, none of them is granted direct input, regardless of which one registered last.
Registration is tied to the lifetime of the view, not to this channel or the returned event. Unlinking the view from the ViewTree (placing it in unconnected_views) reverts ownership to INPUT_PLATFORM_OWNED while retaining the registration, so re-linking fullscreen restores INPUT_CLIENT_OWNED. Destroying the view permanently drops the registration, at which point ownership reverts to the platform.
Calls with virtcon: {} or platform: {} only observe ownership and do not modify the registered direct client.