Allow commands to know they've expired.

Author: timshadel

Sources/Reactor.swift

@@ -18,6 +18,7 @@ public protocol Event {}
 public protocol AnyCommand {
     func _execute(state: Any, core: Any)
     func _canExecute(state: Any) -> Bool
+    func _didExpire(state: Any, core: Any)
 }
 
 extension AnyCommand {
@@ -28,6 +29,7 @@ public protocol Command: AnyCommand {
     associatedtype StateType: State
     func execute(state: StateType, core: Core<StateType>)
     func canExecute(state: StateType) -> Bool
+    func didExpire(state: StateType, core: Core<StateType>)
 }
 
 extension Command {
@@ -36,6 +38,10 @@ extension Command {
         return true
     }
 
+    public func didExpire(state: StateType, core: Core<StateType>) {
+        // do nothing by default
+    }
+
     public func _canExecute(state: Any) -> Bool {
         if let state = state as? StateType {
             return canExecute(state: state)
@@ -44,6 +50,12 @@ extension Command {
         }
     }
 
+    public func _didExpire(state: Any, core: Any) {
+        if let state = state as? StateType, let core = core as? Core<StateType> {
+            didExpire(state: state, core: core)
+        }
+    }
+
     public func _execute(state: Any, core: Any) {
         if let state = state as? StateType, let core = core as? Core<StateType> {
             execute(state: state, core: core)
@@ -196,7 +208,10 @@ public class Core<StateType: State> {
             }
             let now = Date()
             let expired = self.commands.enumerated().filter { $1.expiresAt < now }
-            expired.forEach { self.commands.remove(at: $0.offset) }
+            expired.forEach {
+                self.commands.remove(at: $0.offset)
+                $1.command._didExpire(state: state, core: self)
+            }
             self.middlewares.forEach { $0.middleware._process(event: event, state: state) }
         }
     }