Support Multiple Publishers (again)

EmilioPelaez · Jan 2, 2025 · f9ca3ea · f9ca3ea
1 parent d5edd14
commit f9ca3ea
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Showing 3 changed files with 47 additions and 36 deletions.
diff --git a/Sources/HierarchyResponder/Internal/Publishing/EventPublisherModifier.swift b/Sources/HierarchyResponder/Internal/Publishing/EventPublisherModifier.swift
@@ -34,7 +34,7 @@ struct EventPublisherModifier<E: Event>: ViewModifier {
 
 	func body(content: Content) -> some View {
 		content
-			.publisherRegistrar(for: E.self, id: id, childContainers: $containers)
+			.publisherRegistrar(for: E.self, id: id, publisher: nil, containers: $containers)
 			.onAppearAndChange(of: containers) { containers in
 				updatePublisher(containers: containers, destination: destination)
 			}

diff --git a/Sources/HierarchyResponder/Internal/Publishing/EventSubscriberModifier.swift b/Sources/HierarchyResponder/Internal/Publishing/EventSubscriberModifier.swift
@@ -21,7 +21,6 @@ import SwiftUI
  */
 struct EventSubscriberModifier<E: Event>: ViewModifier {
 	@Environment(\.eventSubscriptionRegistrars) var registrars
-	@Environment(\.responderSafetyLevel) var safetyLevel
 
 	let id: String
 	let publisher: EventPublisher<E>
@@ -34,30 +33,7 @@ struct EventSubscriberModifier<E: Event>: ViewModifier {
 
 	func body(content: Content) -> some View {
 		content
-			.publisherRegistrar(for: E.self, id: id, childContainers: $containers)
-			.onAppearAndChange(of: registrars) { registrars in
-				registerPublisher(registrars, containers: containers)
-			}
-			.onAppearAndChange(of: containers) { containers in
-				registerPublisher(registrars, containers: containers)
-			}
-			.onDisappear(perform: unregisterPublisher)
-	}
-
-	func registerPublisher(_ registrars: RegistrarDictionary, containers: Set<PublishersContainer>) {
-		guard let registrar = registrars[ObjectIdentifier(E.self)] else {
-			let message = "Subscribed to event with no publisher: \(String(describing: E.self))"
-			switch safetyLevel {
-			case .strict: fatalError(message)
-			case .relaxed: return print(message)
-			case .disabled: return
-			}
-		}
-		let container = PublishersContainer(id: id, publisher: publisher, containers: containers)
-		registrar.register(container.id, container)
-	}
-
-	func unregisterPublisher() {
-		registrars[ObjectIdentifier(E.self)]?.register(id, nil)
+			.publisherRegistrar(for: E.self, id: id, publisher: publisher, containers: $containers)
+
 	}
 }
diff --git a/Sources/HierarchyResponder/Internal/Publishing/PublisherRegistrarModifier.swift b/Sources/HierarchyResponder/Internal/Publishing/PublisherRegistrarModifier.swift
@@ -8,23 +8,32 @@
 import SwiftUI
 
 extension View {
-	func publisherRegistrar<E: Event>(for event: E.Type, id: String, childContainers: Binding<Set<PublishersContainer>>) -> some View {
-		modifier(PublisherRegistrarModifier(event: event, id: id, childContainers: childContainers))
+	func publisherRegistrar<E: Event>(for event: E.Type,
+																		id: String,
+																		publisher: EventPublisher<E>?,
+																		containers: Binding<Set<PublishersContainer>>) -> some View {
+		modifier(PublisherRegistrarModifier(event: event,
+																				id: id,
+																				publisher: publisher,
+																				containers: containers))
 	}
 }
 
 struct PublisherRegistrarModifier<E: Event>: ViewModifier {
+	@Environment(\.responderSafetyLevel) var safetyLevel
 	@Environment(\.eventSubscriptionRegistrars) var registrars
 
 	let id: String
-	@Binding var childContainers: Set<PublishersContainer>
+	let publisher: EventPublisher<E>?
+	@Binding var containers: Set<PublishersContainer>
 
 	@State var registrar: EventSubscriptionRegistrar
 
-	init(event: E.Type, id: String, childContainers: Binding<Set<PublishersContainer>>) {
+	init(event: E.Type, id: String, publisher: EventPublisher<E>?, containers: Binding<Set<PublishersContainer>>) {
 		self.id = id
-		self._childContainers = childContainers
-		self._registrar = .init(initialValue: .init(id: id) { _, _ in })
+		self.publisher = publisher
+		self._containers = containers
+		self._registrar = .init(initialValue: .init(id: id + "-empty") { _, _ in })
 	}
 
 	var updatedRegistrars: [ObjectIdentifier: EventSubscriptionRegistrar] {
@@ -36,16 +45,42 @@ struct PublisherRegistrarModifier<E: Event>: ViewModifier {
 	func body(content: Content) -> some View {
 		content
 			.onAppear(perform: createRegistrar)
+			.onAppearAndChange(of: registrars) { registrars in
+				registerPublisher(registrars, containers: containers)
+			}
+			.onAppearAndChange(of: containers) { containers in
+				registerPublisher(registrars, containers: containers)
+			}
 			.environment(\.eventSubscriptionRegistrars, updatedRegistrars)
+			.onDisappear(perform: unregisterPublisher)
 	}
 
 	func createRegistrar() {
 		registrar = .init(id: id) { id, container in
 			if let container {
-				childContainers.update(with: container)
-			} else if let container = childContainers.first(where: { $0.id == id }) {
-				childContainers.remove(container)
+				containers.update(with: container)
+			} else if let container = containers.first(where: { $0.id == id }) {
+				containers.remove(container)
+			}
+		}
+	}
+
+	func registerPublisher(_ registrars: RegistrarDictionary, containers: Set<PublishersContainer>) {
+		guard let registrar = registrars[ObjectIdentifier(E.self)] else {
+			if publisher == nil { return } //	We're on a publisher modifier
+			let message = "Subscribed to event with no publisher: \(String(describing: E.self))"
+			switch safetyLevel {
+			case .strict: fatalError(message)
+			case .relaxed: return print(message)
+			case .disabled: return
 			}
 		}
+		let publisher = self.publisher ?? EventPublisher(id: id) { _ in }
+		let container = PublishersContainer(id: id, publisher: publisher, containers: containers)
+		registrar.register(container.id, container)
+	}
+
+	func unregisterPublisher() {
+		registrars[ObjectIdentifier(E.self)]?.register(id, nil)
 	}
 }