Trait runa_core::client::traits::EventHandler

pub trait EventHandler<Ctx: Client>: 'static {
    type Message;
    type Future<'ctx>: Future<Output = Result<EventHandlerAction, Box<dyn Error + Send + Sync + 'static>>> + 'ctx;

    // Required method
    fn handle_event<'ctx>(
        &'ctx mut self,
        objects: &'ctx mut Ctx::ObjectStore,
        connection: &'ctx mut Ctx::Connection,
        server_context: &'ctx Ctx::ServerContext,
        message: &'ctx mut Self::Message
    ) -> Self::Future<'ctx>;
}

An event handler.

Occasionally, wayland object implementations need to handle events that arise from the compositor. For example, when user moves the pointer, the wl_surface objects maybe need to send motion events to the client.

This can be achieved by implement this trait, and call Client::add_event_handler to register event handlers. Event handlers have an associated event source. Whenever a new event is received, the event source will be polled, and the event handler will be called with the received event.

Required Associated Types

type Message

The event type this event handler expects

type Future<'ctx>: Future<Output = Result<EventHandlerAction, Box<dyn Error + Send + Sync + 'static>>> + 'ctx

Type of future returned by handle_event.

Required Methods

fn handle_event<'ctx>( &'ctx mut self, objects: &'ctx mut Ctx::ObjectStore, connection: &'ctx mut Ctx::Connection, server_context: &'ctx Ctx::ServerContext, message: &'ctx mut Self::Message ) -> Self::Future<'ctx>

Handle an event. Every time an event is received, this will be called, and the returned future will be driven to completion. The returned value indicates whether this event handler should be removed. Event handler is also removed if the event stream has terminated.

This function is not passed a &mut Ctx, because handling events requires exclusive access to the set of event handlers (i.e. the event dispatcher). So we split a Ctx apart, remove the access to the event dispatcher, and only pass the remaining parts.

If an error is returned, the client connection should be closed with an error.

Implementors