module eventbus pub type EventHandlerFn = fn (receiver voidptr, args voidptr, sender voidptr) pub struct Publisher { mut: registry &Registry } pub struct Subscriber { mut: registry &Registry } struct Registry { mut: events []EventHandler } struct EventHandler { name string handler EventHandlerFn receiver voidptr = unsafe { nil } once bool } pub struct EventBus { pub mut: registry &Registry publisher &Publisher subscriber &Subscriber } pub fn new() &EventBus { registry := &Registry{ events: [] } return &EventBus{registry, &Publisher{registry}, &Subscriber{registry}} } // EventBus Methods pub fn (eb &EventBus) publish(name string, sender voidptr, args voidptr) { mut publisher := eb.publisher publisher.publish(name, sender, args) } pub fn (eb &EventBus) clear_all() { mut publisher := eb.publisher publisher.clear_all() } pub fn (eb &EventBus) has_subscriber(name string) bool { return eb.registry.check_subscriber(name) } // Publisher Methods fn (mut pb Publisher) publish(name string, sender voidptr, args voidptr) { for event in pb.registry.events { if event.name == name { event.handler(event.receiver, args, sender) } } pb.registry.events = pb.registry.events.filter(!(it.name == name && it.once)) } fn (mut p Publisher) clear_all() { p.registry.events.clear() } // Subscriber Methods pub fn (mut s Subscriber) subscribe(name string, handler EventHandlerFn) { s.registry.events << EventHandler{ name: name handler: handler } } pub fn (mut s Subscriber) subscribe_method(name string, handler EventHandlerFn, receiver voidptr) { s.registry.events << EventHandler{ name: name handler: handler receiver: receiver } } // unsubscribe_method unsubscribe a receiver for only one method pub fn (mut s Subscriber) unsubscribe_method(name string, receiver voidptr) { s.registry.events = s.registry.events.filter(!(it.name == name && it.receiver == receiver)) } // unsubscribe_receiver unsubscribes a receiver from all events pub fn (mut s Subscriber) unsubscribe_receiver(receiver voidptr) { s.registry.events = s.registry.events.filter(it.receiver != receiver) } pub fn (mut s Subscriber) subscribe_once(name string, handler EventHandlerFn) { s.registry.events << EventHandler{ name: name handler: handler once: true } } pub fn (s &Subscriber) is_subscribed(name string) bool { return s.registry.check_subscriber(name) } // is_subscribed_method checks whether a receiver was already subscribed for any events pub fn (s &Subscriber) is_subscribed_method(name string, receiver voidptr) bool { return s.registry.events.any(it.name == name && it.receiver == receiver) } pub fn (mut s Subscriber) unsubscribe(name string, handler EventHandlerFn) { // v := voidptr(handler) s.registry.events = s.registry.events.filter(!(it.name == name && it.handler == handler)) } // Registry Methods fn (r &Registry) check_subscriber(name string) bool { return r.events.any(it.name == name) }