eventbus: add generic support for event name (#18805)

examples/eventbus/modules/some_module/some_module.v

@@ -3,7 +3,7 @@ module some_module
 import eventbus
 
 const (
-	eb = eventbus.new()
+	eb = eventbus.new[string]()
 )
 
 pub struct Duration {
@@ -29,6 +29,6 @@ pub fn do_work() {
 	some_module.eb.publish('event_baz', &Duration{42}, &EventMetadata{'Additional data at the end.'})
 }
 
-pub fn get_subscriber() eventbus.Subscriber {
+pub fn get_subscriber() eventbus.Subscriber[string] {
 	return *some_module.eb.subscriber
 }

vlib/eventbus/README.md

@@ -4,26 +4,27 @@ A module to provide eventing capabilities using pub/sub.
 
 ## API
 
-1. `new()` - create a new `EventBus`
+1. `new[T]()` - create a new `EventBus`
+2. `EventBus.new[T]()` - create a new `EventBus`
 
 ### Structs:
 
 **EventBus:**
 
-1. `publish(name string, sender voidptr, args voidptr)` - publish an event with provided
+1. `publish(name T, sender voidptr, args voidptr)` - publish an event with provided
     Params & name
 2. `clear_all()` - clear all subscribers
-3. `has_subscriber(name string)` - check if a subscriber to an event exists
+3. `has_subscriber(name T)` - check if a subscriber to an event exists
 
 **Subscriber:**
 
-1. `subscribe(name string, handler EventHandlerFn)` - subscribe to an event
-2. `subscribe_once(name string, handler EventHandlerFn)` - subscribe only once to an event
-3. `subscribe_method(name string, handler EventHandlerFn, receiver voidptr)` - subscribe to
+1. `subscribe(name T, handler EventHandlerFn)` - subscribe to an event
+2. `subscribe_once(name T, handler EventHandlerFn)` - subscribe only once to an event
+3. `subscribe_method(name T, handler EventHandlerFn, receiver voidptr)` - subscribe to
     an event and also set the `receiver` as a parameter.
     Since it's not yet possible to send methods as parameters, this is a workaround.
-4. `is_subscribed(name string)` - check if we are subscribed to an event
-5. `unsubscribe(name string)` - unsubscribe from an event
+4. `is_subscribed(name T)` - check if we are subscribed to an event
+5. `unsubscribe(name T)` - unsubscribe from an event
 
 **Event Handler Signature:**
 
@@ -63,7 +64,7 @@ import eventbus
 
 // initialize it globally
 const (
-	eb = eventbus.new()
+	eb = eventbus.new[string]()
 )
 
 fn main() {
@@ -88,7 +89,7 @@ module main
 
 import eventbus
 
-const eb = eventbus.new()
+const eb = eventbus.new[string]()
 
 struct Work {
 	hours int

vlib/eventbus/eventbus.v

@@ -2,59 +2,70 @@ module eventbus
 
 pub type EventHandlerFn = fn (receiver voidptr, args voidptr, sender voidptr)
 
-pub struct Publisher {
+pub struct Publisher[T] {
 mut:
-	registry &Registry = unsafe { nil }
+	registry &Registry[T] = unsafe { nil }
 }
 
-pub struct Subscriber {
+pub struct Subscriber[T] {
 mut:
-	registry &Registry = unsafe { nil }
+	registry &Registry[T] = unsafe { nil }
 }
 
-struct Registry {
+struct Registry[T] {
 mut:
-	events []EventHandler
+	events []EventHandler[T]
 }
 
-struct EventHandler {
-	name     string
+struct EventHandler[T] {
+	name     T
 	handler  EventHandlerFn
 	receiver voidptr = unsafe { nil }
 	once     bool
 }
 
-pub struct EventBus {
+pub struct EventBus[T] {
 pub mut:
-	registry   &Registry   = unsafe { nil }
-	publisher  &Publisher  = unsafe { nil }
-	subscriber &Subscriber = unsafe { nil }
+	registry   &Registry[T]   = unsafe { nil }
+	publisher  &Publisher[T]  = unsafe { nil }
+	subscriber &Subscriber[T] = unsafe { nil }
 }
 
-pub fn new() &EventBus {
-	registry := &Registry{
+// EventBus.new[T] create a new eventbus with event type T.
+pub fn EventBus.new[T]() &EventBus[T] {
+	registry := &Registry[T]{
 		events: []
 	}
-	return &EventBus{registry, &Publisher{registry}, &Subscriber{registry}}
+	return &EventBus[T]{registry, &Publisher[T]{registry}, &Subscriber[T]{registry}}
 }
 
-// EventBus Methods
-pub fn (eb &EventBus) publish(name string, sender voidptr, args voidptr) {
+// new[T] create a new eventbus with event type T.
+pub fn new[T]() &EventBus[T] {
+	registry := &Registry[T]{
+		events: []
+	}
+	return &EventBus[T]{registry, &Publisher[T]{registry}, &Subscriber[T]{registry}}
+}
+
+// publish publish an event with provided Params & name.
+pub fn (eb &EventBus[T]) publish(name T, sender voidptr, args voidptr) {
 	mut publisher := eb.publisher
 	publisher.publish(name, sender, args)
 }
 
-pub fn (eb &EventBus) clear_all() {
+// clear_all clear all subscribers.
+pub fn (eb &EventBus[T]) clear_all() {
 	mut publisher := eb.publisher
 	publisher.clear_all()
 }
 
-pub fn (eb &EventBus) has_subscriber(name string) bool {
+// has_subscriber check if a subscriber to an event exists.
+pub fn (eb &EventBus[T]) has_subscriber(name T) bool {
 	return eb.registry.check_subscriber(name)
 }
 
-// Publisher Methods
-fn (mut pb Publisher) publish(name string, sender voidptr, args voidptr) {
+// publish publish an event with provided Params & name.
+fn (mut pb Publisher[T]) publish(name T, sender voidptr, args voidptr) {
 	for event in pb.registry.events {
 		if event.name == name {
 			event.handler(event.receiver, args, sender)
@@ -63,59 +74,64 @@ fn (mut pb Publisher) publish(name string, sender voidptr, args voidptr) {
 	pb.registry.events = pb.registry.events.filter(!(it.name == name && it.once))
 }
 
-fn (mut p Publisher) clear_all() {
+// clear_all clear all subscribers.
+fn (mut p Publisher[T]) clear_all() {
 	p.registry.events.clear()
 }
 
-// Subscriber Methods
-pub fn (mut s Subscriber) subscribe(name string, handler EventHandlerFn) {
-	s.registry.events << EventHandler{
+// subscribe subscribe to an event `name`.
+pub fn (mut s Subscriber[T]) subscribe(name T, handler EventHandlerFn) {
+	s.registry.events << EventHandler[T]{
 		name: name
 		handler: handler
 	}
 }
 
-pub fn (mut s Subscriber) subscribe_method(name string, handler EventHandlerFn, receiver voidptr) {
-	s.registry.events << EventHandler{
+// subscribe_method subscribe to an event `name` and also set the `receiver` as a parameter.
+pub fn (mut s Subscriber[T]) subscribe_method(name T, handler EventHandlerFn, receiver voidptr) {
+	s.registry.events << EventHandler[T]{
 		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) {
+// unsubscribe_method unsubscribe a receiver for only one method.
+pub fn (mut s Subscriber[T]) unsubscribe_method(name T, 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) {
+// unsubscribe_receiver unsubscribes a receiver from all events.
+pub fn (mut s Subscriber[T]) 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{
+// subscribe_once subscribe only once to an event `name`.
+pub fn (mut s Subscriber[T]) subscribe_once(name T, handler EventHandlerFn) {
+	s.registry.events << EventHandler[T]{
 		name: name
 		handler: handler
 		once: true
 	}
 }
 
-pub fn (s &Subscriber) is_subscribed(name string) bool {
+// is_subscribed check if we are subscribed to an event `name`.
+pub fn (s &Subscriber[T]) is_subscribed(name T) 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 {
+// is_subscribed_method checks whether a receiver was already subscribed for any events.
+pub fn (s &Subscriber[T]) is_subscribed_method(name T, receiver voidptr) bool {
 	return s.registry.events.any(it.name == name && it.receiver == receiver)
 }
 
-pub fn (mut s Subscriber) unsubscribe(name string, handler EventHandlerFn) {
+// unsubscribe unsubscribe from an event `name`.
+pub fn (mut s Subscriber[T]) unsubscribe(name T, 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 {
+fn (r &Registry[T]) check_subscriber(name T) bool {
 	return r.events.any(it.name == name)
 }

vlib/eventbus/eventbus_test.v

@@ -8,11 +8,12 @@ struct FakeReceiver {
 	ok bool
 }
 
-fn test_eventbus() {
+fn test_eventbus_string() {
 	ev_data := &EventData{'hello'}
-	mut eb := eventbus.new()
+	mut eb := eventbus.new[string]()
 	eb.subscriber.subscribe_once('on_test', on_test)
 	assert eb.has_subscriber('on_test')
+	assert !eb.has_subscriber('not_exist')
 	assert eb.subscriber.is_subscribed('on_test')
 	eb.publish('on_test', eb, ev_data)
 	assert !eb.has_subscriber('on_test')
@@ -25,10 +26,52 @@ fn test_eventbus() {
 	assert !eb.subscriber.is_subscribed('on_test')
 }
 
+enum Events {
+	event_1
+	event_2
+	event_3
+}
+
+fn test_eventbus_enum() {
+	ev_data := &EventData{'hello'}
+	mut eb := eventbus.EventBus.new[Events]()
+	eb.subscriber.subscribe_once(Events.event_1, on_test)
+	assert eb.has_subscriber(Events.event_1)
+	assert !eb.has_subscriber(Events.event_2)
+	assert eb.subscriber.is_subscribed(Events.event_1)
+	eb.publish(Events.event_1, eb, ev_data)
+	assert !eb.has_subscriber(Events.event_1)
+	assert !eb.subscriber.is_subscribed(Events.event_1)
+	eb.subscriber.subscribe(Events.event_1, on_test)
+	assert eb.has_subscriber(Events.event_1)
+	assert eb.subscriber.is_subscribed(Events.event_1)
+	eb.clear_all()
+	assert !eb.has_subscriber(Events.event_1)
+	assert !eb.subscriber.is_subscribed(Events.event_1)
+}
+
+fn test_eventbus_int() {
+	ev_data := &EventData{'hello'}
+	mut eb := eventbus.EventBus.new[int]()
+	eb.subscriber.subscribe_once(9999, on_test)
+	assert eb.has_subscriber(9999)
+	assert !eb.has_subscriber(1111)
+	assert eb.subscriber.is_subscribed(9999)
+	eb.publish(9999, eb, ev_data)
+	assert !eb.has_subscriber(9999)
+	assert !eb.subscriber.is_subscribed(9999)
+	eb.subscriber.subscribe(9999, on_test)
+	assert eb.has_subscriber(9999)
+	assert eb.subscriber.is_subscribed(9999)
+	eb.clear_all()
+	assert !eb.has_subscriber(9999)
+	assert !eb.subscriber.is_subscribed(9999)
+}
+
 fn test_subscribe_method() {
 	// Does not really test subscribe_method idinvidually though
 	// given
-	mut eb := eventbus.new()
+	mut eb := eventbus.new[string]()
 	r := FakeReceiver{}
 
 	assert !eb.subscriber.is_subscribed_method('on_test_with_receiver', r)
@@ -41,7 +84,7 @@ fn test_subscribe_method() {
 
 fn test_unsubscribe_method() {
 	// given
-	mut eb := eventbus.new()
+	mut eb := eventbus.new[string]()
 	r := FakeReceiver{}
 	r2 := FakeReceiver{}
 
@@ -58,7 +101,7 @@ fn test_unsubscribe_method() {
 fn test_publish() {
 	// given
 	ev_data := &EventData{'hello'}
-	mut eb := eventbus.new()
+	mut eb := eventbus.new[string]()
 
 	// when
 	eb.subscriber.subscribe_once('on_test', on_test)
@@ -71,7 +114,7 @@ fn test_publish() {
 
 fn test_publish_with_receiver() {
 	// given
-	mut eb := eventbus.new()
+	mut eb := eventbus.new[string]()
 	ev_data := &EventData{'hello'}
 	r := FakeReceiver{}
 
@@ -85,7 +128,7 @@ fn test_publish_with_receiver() {
 
 fn test_unsubscribe_reveiver() {
 	// given
-	mut eb := eventbus.new()
+	mut eb := eventbus.new[string]()
 	r := &FakeReceiver{}
 
 	// when

vlib/v/tests/fn_voidptr_param_call_with_nonpointer_rvalue_test.v

@@ -5,7 +5,7 @@ struct MyMessage {
 }
 
 fn test_fn_call_with_nonpointer_rvalue() {
-	eb := eventbus.new()
+	eb := eventbus.new[string]()
 	mut subscriber := eb.subscriber
 
 	subscriber.subscribe('my_publish', subscriber_method)
@@ -18,6 +18,6 @@ fn subscriber_method(receiver voidptr, ev &MyMessage, sender voidptr) {
 	println(ev)
 }
 
-fn do_something(eb &eventbus.EventBus) {
+fn do_something[T](eb &eventbus.EventBus[T]) {
 	eb.publish('my_publish', eb, MyMessage{ msg: 'this is my message' })
 }