Struct EventHandlerRegistry 

pub struct EventHandlerRegistry { /* private fields */ }

Registry for maintaining event handlers.

Example

impl Host for MyHost {
    fn on_event(
        &mut self,
        process: &mut ProcessState,
        event_id: u32,
    ) -> Result<(), EventError> {
        if self
            .event_handlers
            .handle_event(event_id, process)
            .map_err(|err| EventError::HandlerError { id: event_id, err })?
        {
            // the event was handled by the registered event handlers; just return
            return Ok(());
        }

        // implement custom event handling

        Err(EventError::UnhandledEvent { id: event_id })
    }
}

Implementations

impl EventHandlerRegistry

pub fn new() -> Self

pub fn register( &mut self, event: EventName, handler: Arc<dyn EventHandler>, ) -> Result<(), ExecutionError>

Registers an EventHandler with a given event name.

The EventId is computed from the event name during registration.

Errors

Returns an error if:

• The event is a reserved system event
• A handler with the same event ID is already registered

pub fn unregister(&mut self, id: EventId) -> bool

Unregisters a handler with the given identifier, returning a flag whether a handler with that identifier was previously registered.

pub fn resolve_event(&self, id: EventId) -> Option<&EventName>

Returns the EventName registered for id, if any.

pub fn handle_event( &self, id: EventId, process: &ProcessState<'_>, ) -> Result<Option<Vec<AdviceMutation>>, EventError>

Handles the event if the registry contains a handler with the same identifier.

Returns an Option<_> indicating whether the event was handled. Returns None if the event was not handled, Some(mutations) if it was handled successfully, and propagates handler errors to the caller.

Trait Implementations

impl Debug for EventHandlerRegistry

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for EventHandlerRegistry

fn default() -> EventHandlerRegistry

Returns the “default value” for a type.