Vous connaissez le concept du Pub/Sub? C'est trop bien le Pub/Sub! C'est super pratique pour les projets amateurs parce que ça aide à garder le code propre au fur et à mesure qu'il grandit!
Vous savez quel langage n'avait pas de Pub/Sub jusqu'ici ? Purebasic! Mais ça, c'était avant.
Code : Tout sélectionner
;============================================================
; PubSub.pbi
;
; Lightweight pub-sub for PureBasic apps. Independent of PureBasic's built-in event loop: use any integer as an event ID and route it through Subscribe / Emit.
;
; Features:
; - Subscribe / Unsubscribe / Emit
; - Clear / ClearAll
; - Optional payload pointer carried to every listener
; - Listener priorities (higher fires first)
; - One-shot listeners (auto-removed after their first call)
; - Safe under re-entrant emits from inside a callback
;
; Usage:
; Procedure OnSomething(EventID, *Payload)
; Debug "fired: " + EventID
; EndProcedure
;
; PubSub::Subscribe(#MyEvent, @OnSomething(), PubSub::#Priority_High)
; PubSub::Emit(#MyEvent)
;
DeclareModule PubSub
; Callback signature. Every listener gets the event ID it was fired for and the *Payload pointer that the emitter passed (which may be #Null).
Prototype Listener(EventID, *Payload)
Enumeration ; Priority shortcuts. Any integer works; these are just helpers.
#Priority_Lowest = -1000
#Priority_Low = -100
#Priority_Normal = 0
#Priority_High = 100
#Priority_Highest = 1000
EndEnumeration
; Public procedures declaration
Declare Subscribe(EventID.i, *Callback.Listener, Priority.l = #Priority_Normal, OneShot.a = #False)
Declare Unsubscribe(EventID.i, *Callback.Listener)
Declare Emit(EventID.i, *Payload = #Null)
Declare Clear(EventID.i)
Declare ClearAll()
Declare.i ListenerCount(EventID.i)
EndDeclareModule
Module PubSub
EnableExplicit
; Private variables, structures and constants
Structure ListenerEntry
Callback.i
Priority.l
OneShot.a
EndStructure
Structure EventBucket
EventID.i
List Listeners.ListenerEntry()
EndStructure
Global NewMap Events.EventBucket()
; Public procedures
Procedure Subscribe(EventID.i, *Callback.Listener, Priority.l = #Priority_Normal, OneShot.a = #False)
Protected Key.s = Str(EventID)
Protected Inserted = #False
If Not FindMapElement(Events(), Key)
AddMapElement(Events(), Key)
Events()\EventID = EventID
EndIf
; Insert before the first existing listener with strictly lower priority, so equal-priority listeners preserve subscription order (FIFO).
ForEach Events()\Listeners()
If Events()\Listeners()\Priority < Priority
InsertElement(Events()\Listeners())
Inserted = #True
Break
EndIf
Next
If Not Inserted
LastElement(Events()\Listeners())
AddElement(Events()\Listeners())
EndIf
Events()\Listeners()\Callback = *Callback
Events()\Listeners()\Priority = Priority
Events()\Listeners()\OneShot = OneShot
EndProcedure
Procedure Unsubscribe(EventID.i, *Callback.Listener)
Protected Key.s = Str(EventID)
If Not FindMapElement(Events(), Key)
ProcedureReturn
EndIf
ForEach Events()\Listeners()
If Events()\Listeners()\Callback = *Callback
DeleteElement(Events()\Listeners())
Break
EndIf
Next
If ListSize(Events()\Listeners()) = 0
DeleteMapElement(Events())
EndIf
EndProcedure
Procedure Emit(EventID.i, *Payload = #Null)
Protected Key.s = Str(EventID)
Protected i, Count
Protected Cb.Listener
If Not FindMapElement(Events(), Key)
ProcedureReturn
EndIf
Count = ListSize(Events()\Listeners())
If Count = 0
ProcedureReturn
EndIf
; Snapshot listeners before firing; a callback may Subscribe, Unsubscribe, Clear, or Emit recursively, and we must not let that corrupt iteration of the live list.
Protected Dim Snapshot.ListenerEntry(Count - 1)
i = 0
ForEach Events()\Listeners()
Snapshot(i)\Callback = Events()\Listeners()\Callback
Snapshot(i)\Priority = Events()\Listeners()\Priority
Snapshot(i)\OneShot = Events()\Listeners()\OneShot
i + 1
Next
; Fire snapshot in stored order (already priority-sorted).
For i = 0 To Count - 1
Cb = Snapshot(i)\Callback
Cb(EventID, *Payload)
Next
; Sweep one-shots that fired. The bucket may have been mutated
; or removed by a recursive call, so re-find before touching.
If FindMapElement(Events(), Key)
For i = 0 To Count - 1
If Snapshot(i)\OneShot
ForEach Events()\Listeners()
If Events()\Listeners()\Callback = Snapshot(i)\Callback And Events()\Listeners()\OneShot
DeleteElement(Events()\Listeners())
Break
EndIf
Next
EndIf
Next
If ListSize(Events()\Listeners()) = 0
DeleteMapElement(Events())
EndIf
EndIf
EndProcedure
Procedure Clear(EventID.i)
Protected Key.s = Str(EventID)
If FindMapElement(Events(), Key)
DeleteMapElement(Events())
EndIf
EndProcedure
Procedure ClearAll()
ClearMap(Events())
EndProcedure
Procedure.i ListenerCount(EventID.i)
Protected Key.s = Str(EventID)
If FindMapElement(Events(), Key)
ProcedureReturn ListSize(Events()\Listeners())
EndIf
ProcedureReturn 0
EndProcedure
EndModule
CompilerIf #PB_Compiler_IsMainFile
XIncludeFile "PubSub.pbi"
#Event_Hello = 1
#Event_Bye = 2
Procedure A(EventID, *Payload)
Debug "A fired on " + EventID
EndProcedure
Procedure B(EventID, *Payload)
Debug "B fired on " + EventID + " payload=" + PeekS(*Payload)
EndProcedure
Procedure Once(EventID, *Payload)
Debug "one-shot fired on " + EventID
EndProcedure
PubSub::Subscribe(#Event_Hello, @A(), PubSub::#Priority_Low)
PubSub::Subscribe(#Event_Hello, @B(), PubSub::#Priority_High) ; fires before A
PubSub::Subscribe(#Event_Hello, @Once(), PubSub::#Priority_Normal, #True)
Define msg.s = "world"
PubSub::Emit(#Event_Hello, @msg) ; B, Once, A
PubSub::Emit(#Event_Hello, @msg) ; B, A (Once is gone)
Debug "listeners on #Event_Hello: " + PubSub::ListenerCount(#Event_Hello)
PubSub::ClearAll()
Debug "after ClearAll: " + PubSub::ListenerCount(#Event_Hello)
CompilerEndIf
