From 43ba6766ba1902797b01d8af00e0e730239f2578 Mon Sep 17 00:00:00 2001
From: Abdullah Atta <thecodrr@protonmail.com>
Date: Wed, 22 Jan 2020 21:41:08 +0500
Subject: [PATCH] improve eventbus

---
 examples/eventbus/eventbus.v                  |   7 +-
 .../modules/some_module/some_module.v         |  13 +-
 vlib/eventbus/README.md                       |  82 ++++------
 vlib/eventbus/eventbus.v                      | 141 +++++++++---------
 vlib/eventbus/eventbus_test.v                 |  47 ++----
 vlib/eventbus/params.v                        |  99 ------------
 6 files changed, 115 insertions(+), 274 deletions(-)
 delete mode 100644 vlib/eventbus/params.v

diff --git a/examples/eventbus/eventbus.v b/examples/eventbus/eventbus.v
index 5480f8f299..e4d45f0403 100644
--- a/examples/eventbus/eventbus.v
+++ b/examples/eventbus/eventbus.v
@@ -2,7 +2,6 @@ module main
 
 import (
 	some_module
-	eventbus
 )
 
 fn main(){
@@ -11,8 +10,6 @@ fn main(){
 	some_module.do_work()
 }
 
-fn on_error(sender voidptr, p eventbus.Params) {
-	work := *(*some_module.Work(sender))
-	println(work.hours)
-	println(p.get_string("error"))
+fn on_error(sender voidptr, e &some_module.Error) {
+	println(e.message)
 }
diff --git a/examples/eventbus/modules/some_module/some_module.v b/examples/eventbus/modules/some_module/some_module.v
index 6963209480..f30f720985 100644
--- a/examples/eventbus/modules/some_module/some_module.v
+++ b/examples/eventbus/modules/some_module/some_module.v
@@ -13,19 +13,22 @@ pub struct Work {
 	hours int
 }
 
+pub struct Error {
+	pub:
+	message string
+}
+
 pub fn do_work(){
 	work := Work{20}
-	mut params := eventbus.Params{}
 	for i in 0..20 {
 		println("working...")
 		if i == 15 {
-			params.put_string("error", "CRASH!!")
-			eb.publish("error", work, params)
-			eb.publish("error", work, params)
+			error := &Error{"There was an error."}
+			eb.publish("error", work, error)
+			eb.publish("error", work, error)
 			return
 		}
 	}
-	
 }
 
 pub fn get_subscriber() eventbus.Subscriber {
diff --git a/vlib/eventbus/README.md b/vlib/eventbus/README.md
index b9e4404557..1d13c31bf9 100644
--- a/vlib/eventbus/README.md
+++ b/vlib/eventbus/README.md
@@ -10,27 +10,36 @@ A module to provide eventing capabilities using pub/sub.
 
 **EventBus:**
 
-1. `publish(string, voidptr, Params)` - publish an event with provided Params & name
+1. `publish(name string, sender voidptr, args voidptr)` - publish an event with provided Params & name
 2. `clear_all()` - clear all subscribers
-3. `has_subscriber(string)` - check if a subscriber to an event exists
+3. `has_subscriber(name string)` - check if a subscriber to an event exists
 
 **Subscriber:**
 
-1. `subscribe(string, fn(voidptr, Params))` - subscribe to an event
-2. `subscribe_once(string, fn(voidptr, Params))` - subscribe only once to an event
-3. `is_subscribed(string)` - check if we are subscribed to an event
-4. `unsubscribe(string)` - unsubscribe from an event
+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, reciever voidptr)` - subscribe to an event and also recieve the `reciever` as a parameter. Since it's not yet possible to send methods as parameters, this is the workaround.
+4. `is_subscribed(name string)` - check if we are subscribed to an event
+5. `unsubscribe(name string)` - unsubscribe from an event
 
 **Event Handler Signature:**
 
-The function given to `subscribe` and `subscribe_once` must match this:
+The function given to `subscribe`, `subscribe_method` and `subscribe_once` must match this:
 
 ```v
-fn(voidptr, Params){
+fn(voidptr, voidptr, voidptr){
 
 }
-// Example
-fn onPress(sender voidptr, p Params){
+
+// Since V can map structs to voidptr, this also works
+struct ClickEvent {
+    x int
+    y int
+}
+
+// Example case where publisher sends ClickEvent as args.
+fn onPress(sender voidptr, e &ClickEvent){
+    println(e.x)
     //your code here...
 }
 ```
@@ -62,13 +71,8 @@ fn main(){
 }
 
 // the event handler
-fn on_error(sender voidptr, p eventbus.Params) {
-    //cast the sender to the real type
-    //you can also make this mutable if required.
-    work := *(*Work(sender)) //a little verbose but works
-
-    error := p.get_string("error")
-	println('error occured on ${work.hours}. Error: ${error}')
+fn on_error(work &Work, e &Error) {
+	println('error occured on ${work.hours}. Error: ${e.message}')
 }
 ```
 
@@ -77,55 +81,23 @@ fn on_error(sender voidptr, p eventbus.Params) {
 ```v
 module main
 
-import (
-	eventbus
-)
-
 struct Work{
     hours int
 }
 
+struct Error {
+    message string
+}
+
 fn do_work(){
     work := Work{20}
     // get a mutable Params instance & put some data into it
-	mut params := eventbus.Params{}
-    params.put_string("error", "Error: no internet connection.")
+	error := &Error{"Error: no internet connection."}
     // publish the event
-    eb.publish("error", work, params)
+    eb.publish("error", work, error)
 }
 ```
 
-### How to use `Params`:
-
-```v
-mut params := eventbus.Params{}
-
-params.put_string("string", "some_string")
-params.put_int("int", 20)
-params.put_bool("bool", true)
-
-// add maps and arrays of any type like this
-arr := [1,2,3]
-params.put_array("array", arr)
-mp :=  {"hello": "world"}
-params.put_map("map", mp)
-
-//get and use the params like this
-assert params.get_string("string") == "some_string"
-assert params.get_int("int") == 20
-assert params.get_bool("bool") == true
-
-g_arr := params.get_array("array", 0)
-assert g_arr[0] == 1
-
-g_m := params.get_map("map", "")
-assert g_m["hello"] == "world"
-```
-
-#### Caution when putting arrays:
-
-Currently putting arrays and maps directly as parameters in `put_array` doesn't work, so make a variable first and use that.
-
 ### Notes:
 
 1. Each `EventBus` instance has it's own registry (i.e. there is no global event registry so you can't just subscribe to an event wherever you are.
diff --git a/vlib/eventbus/eventbus.v b/vlib/eventbus/eventbus.v
index 628556365a..6a5f45f915 100644
--- a/vlib/eventbus/eventbus.v
+++ b/vlib/eventbus/eventbus.v
@@ -1,55 +1,55 @@
 module eventbus
 
+pub type EventHandlerFn fn(voidptr, voidptr, voidptr)
+
 pub struct Publisher {
-	mut:
+mut:
 	registry &Registry
 }
 
 pub struct Subscriber {
-	mut:
+mut:
 	registry &Registry
 }
 
-struct Registry{
-	mut:
-	names []string
-	events []voidptr
-	once []string
+struct Registry {
+mut:
+	events []EventHandler
 }
 
 struct EventHandler {
-	func fn(voidptr, Params)
+	name string
+	handler EventHandlerFn
+	receiver voidptr
+	once bool
 }
 
-pub struct EventBus{
-	pub mut:
-	registry &Registry
-	publisher &Publisher
-	pub:
+pub struct EventBus {
+pub mut:
+	registry   &Registry
+	publisher  &Publisher
+pub:
 	subscriber &Subscriber
 }
 
-pub fn new() &EventBus{
+pub fn new() &EventBus {
 	registry := &Registry{
-		names: []
 		events: []
-		once: []
 	}
 	return &EventBus{
-		registry,
-		&Publisher{registry},
-		&Subscriber{registry}
+		registry,&Publisher{
+			registry},&Subscriber{
+			registry}
 	}
 }
 
 // EventBus Methods
-
-pub fn (eb &EventBus) publish(name string, sender voidptr, p Params) {
+pub fn (eb &EventBus) publish(name string, sender voidptr, args voidptr) {
 	mut publisher := eb.publisher
-	publisher.publish(name, sender, p)
+	publisher.publish(name, sender, args)
 }
 
-pub fn (eb &EventBus) clear_all(){
+pub fn (eb &EventBus) clear_all() {
 	mut publisher := eb.publisher
 	publisher.clear_all()
 }
@@ -59,80 +59,77 @@ pub fn (eb &EventBus) has_subscriber(name string) bool {
 }
 
 // Publisher Methods
-
-fn (pb mut Publisher) publish(name string, sender voidptr, p Params){
-	//p.put_custom("sender", "any", sender) //add sender to params
-	for i, n in pb.registry.names {
-		if name == n {
-			eh := pb.registry.events[i]
-			once_index := pb.registry.once.index(pb.registry.names[i])
-			if once_index > -1 {
+fn (pb mut Publisher) publish(name string, sender voidptr, args voidptr) {
+	for i, event in pb.registry.events {
+		if event.name == name {
+			if event.once {
 				pb.registry.events.delete(i)
-				pb.registry.names.delete(i)
-				pb.registry.once.delete(once_index)
 			}
-			invoke(eh, sender, p)
+			if event.receiver != voidptr(0) {
+				event.handler(event.receiver, args, sender)
+			} else {
+				event.handler(sender, args, voidptr(0))
+			}
 		}
 	}
 }
 
-fn (p mut Publisher) clear_all(){
-	if p.registry.names.len == 0 {return}
-	for i := p.registry.names.len - 1; i >= 0; i-- {
-		p.registry.delete_entry(i)
+fn (p mut Publisher) clear_all() {
+	if p.registry.events.len == 0 {
+		return
+	}
+	for i := p.registry.events.len - 1; i >= 0; i-- {
+		p.registry.events.delete(i)
 	}
 }
 
 // Subscriber Methods
-
-pub fn (s mut Subscriber) subscribe(name string, handler fn(voidptr, Params)){
-	s.registry.names << name
-	v := voidptr(handler)
-	s.registry.events << v
+pub fn (s mut Subscriber) subscribe(name string, handler EventHandlerFn) {
+	s.registry.events << EventHandler {
+		name: name
+		handler: handler
+		receiver: voidptr(0)
+	}
 }
 
-pub fn (s mut Subscriber) subscribe_once(name string, handler fn(voidptr, Params)){
-	s.subscribe(name, handler)
-	s.registry.once << name
+pub fn (s mut Subscriber) subscribe_method(name string, handler EventHandlerFn, receiver voidptr) {
+	s.registry.events << EventHandler {
+		name: name
+		handler: handler
+		receiver: receiver
+	}
+}
+
+pub fn (s mut Subscriber) subscribe_once(name string, handler EventHandlerFn) {
+	s.registry.events << EventHandler {
+		name: name
+		handler: handler
+		receiver: voidptr(0)
+		once: true
+	}
 }
 
 pub fn (s &Subscriber) is_subscribed(name string) bool {
 	return s.registry.check_subscriber(name)
 }
 
-pub fn (s mut Subscriber) unsubscribe(name string, handler fn(voidptr, Params)){
-	v := voidptr(handler)
-	for i, n in s.registry.names {
-		if name == n {
-			eh := s.registry.events[i]
-			if eh == v {
-				s.registry.delete_entry(i)
+pub fn (s mut Subscriber) unsubscribe(name string, handler EventHandlerFn) {
+	// v := voidptr(handler)
+	for i, event in s.registry.events {
+		if event.name == name {
+			if event.handler == handler {
+				s.registry.events.delete(i)
 			}
 		}
 	}
 }
 
 // Registry Methods
-
 fn (r &Registry) check_subscriber(name string) bool {
-	for n in r.names {
-		if name == n {return true}
+	for event in r.events {
+		if event.name == name {
+			return true
+		}
 	}
 	return false
 }
-
-fn (r mut Registry) delete_entry(index int) {
-	once_index := r.once.index(r.names[index])
-	if once_index > -1 {
-		r.once.delete(once_index)
-	}
-	r.events.delete(index)
-	r.names.delete(index)
-}
-
-// Helper Functions
-
-fn invoke(p, sender voidptr, arr Params){
-	handler := EventHandler{p}.func
-	handler(sender, arr)
-}
diff --git a/vlib/eventbus/eventbus_test.v b/vlib/eventbus/eventbus_test.v
index 8c76d77882..173188459c 100644
--- a/vlib/eventbus/eventbus_test.v
+++ b/vlib/eventbus/eventbus_test.v
@@ -2,17 +2,19 @@ import (
 	eventbus
 )
 
+struct EventData {
+	data	string
+}
+
 fn test_eventbus(){
+	ev_data := &EventData{'hello'}
 	mut eb := eventbus.new()
 	eb.subscriber.subscribe_once("on_test", on_test)
 	
 	assert eb.has_subscriber("on_test")
 	assert eb.subscriber.is_subscribed("on_test")
 
-	mut params := eventbus.Params{}
-	params.put_string("eventbus", "vevent")
-
-	eb.publish("on_test", eb, params)
+	eb.publish("on_test", eb, ev_data)
 
 	assert !eb.has_subscriber("on_test")
 	assert !eb.subscriber.is_subscribed("on_test")
@@ -28,37 +30,6 @@ fn test_eventbus(){
 	assert !eb.subscriber.is_subscribed("on_test")
 }
 
-fn test_params(){
-	mut params := eventbus.Params{}
-
-	params.put_string("string", "some_string")
-	params.put_int("int", 20)
-	params.put_bool("bool", true)
-	arr := [1,2,3]
-	params.put_array("array", arr)
-	mp :=  {"hello": "world"}
-	params.put_map("map", mp)
-
-	assert params.get_string("string") == "some_string"
-	assert params.get_int("int") == 20
-	assert params.get_bool("bool") == true
-
-	g_arr := params.get_array("array", 0)
-	assert g_arr[0] == 1 
-
-	g_m := params.get_map("map", "")
-	assert g_m["hello"] == "world"
-}
-
-fn on_test(sender voidptr, p eventbus.Params) {
-	mut eb := *(*eventbus.EventBus(sender))
-	
-	eb.subscriber.subscribe("on_test_2", on_test_2)
-	eb.clear_all()
-	assert !eb.has_subscriber("on_test_2")
-	assert !eb.subscriber.is_subscribed("on_test_2")
-
-	assert p.get_string("eventbus") == "vevent"
-}
-
-fn on_test_2(sender voidptr, p eventbus.Params){}
+fn on_test(sender voidptr, ev &EventData) {
+	assert ev.data == "hello"
+}
\ No newline at end of file
diff --git a/vlib/eventbus/params.v b/vlib/eventbus/params.v
deleted file mode 100644
index 1ddbb4aa1d..0000000000
--- a/vlib/eventbus/params.v
+++ /dev/null
@@ -1,99 +0,0 @@
-module eventbus
-
-/*
-NOTE: All these non-generic methods are temporary until
-V has a properly functioning generic system
-*/
-
-pub struct Params {
-	mut:
-	params []Param
-}
-
-struct Param{
-	typ string
-	name string
-	value voidptr
-}
-
-pub fn (p Params) get_string(name string) string {
-	param, is_type := p.get_param(name, "string")
-	return if is_type {string(byteptr(param.value))}else{""}
-}
-
-pub fn (p Params) get_int(name string) int {
-	param, is_type := p.get_param(name, "num")
-	return if is_type {int(param.value)}else{0}
-}
-
-pub fn (p Params) get_bool(name string) bool {
-	param, is_type := p.get_param(name, "bool")
-	return if is_type {int(param.value) == 1}else{false}
-}
-
-pub fn (p Params) get_array<T>(name string, def T) []T {
-	param, is_type := p.get_param(name, "array")
-	if is_type {
-		val := param.value
-		return unmarshall_array(def, val)
-	} else {
-		return []
-	}
-}
-
-pub fn (p Params) get_map<T>(name string, def T) map[string]T {
-	param, is_type := p.get_param(name, "map")
-	if is_type {
-		val := param.value
-		return unmarshall_map(def, val)
-	} else {
-		return map[string]T
-	}
-}
-
-pub fn (p Params) get_raw(name string) voidptr {
-	param, _ := p.get_param(name, "")
-	return param.value
-}
-
-pub fn (p mut Params) put_map(name string, value voidptr) {
-	p.put_custom(name, "map", value)
-}
-
-pub fn (p mut Params) put_array(name string, arr voidptr) {
-	p.put_custom(name, "array", arr)
-}
-
-pub fn (p mut Params) put_int(name string, num int) {
-	p.put_custom(name, "num", num)
-}
-
-pub fn (p mut Params) put_string(name string, s string) {
-	p.put_custom(name, "string", s.str)
-}
-
-pub fn (p mut Params) put_bool(name string, val bool) {
-	p.put_custom(name, "bool", if val { 1 } else { 0 })
-}
-
-pub fn (p mut Params) put_custom(name, typ string, data voidptr) {
-	p.params << Param {typ, name, data}
-}
-
-//HELPERS
-fn (p Params) get_param(name string, typ string) (Param, bool) {
-	for param in p.params {
-		if param.name == name {
-			return param, param.typ == typ
-		}
-	}
-	return Param{value: voidptr(0)}, false
-}
-
-fn unmarshall_array<T> (s T, m voidptr) array_T {
-	return *(*array_T(m))
-}
-
-fn unmarshall_map<T> (s T, m voidptr) map_T {
-	return *(*map_T(m))
-}