Add modern listener method

Fixes #46
sindresorhus · Mar 30, 2022 · 0dcedd5 · 0dcedd5
1 parent 7e251f3
commit 0dcedd5
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Showing 3 changed files with 160 additions and 43 deletions.
diff --git a/Example/KeyboardShortcutsExample/MainScreen.swift b/Example/KeyboardShortcutsExample/MainScreen.swift
@@ -105,10 +105,6 @@ private struct DoubleShortcut: View {
 					isPressed1 = true
 				}
 
-				KeyboardShortcuts.onKeyUp(for: .testShortcut1) {
-					isPressed1 = false
-				}
-
 				KeyboardShortcuts.onKeyDown(for: .testShortcut2) {
 					isPressed2 = true
 				}
@@ -117,6 +113,11 @@ private struct DoubleShortcut: View {
 					isPressed2 = false
 				}
 			}
+			.task {
+				for await _ in KeyboardShortcuts.on(.keyUp, for: .testShortcut1) {
+					isPressed1 = false
+				}
+			}
 	}
 }
 

diff --git a/Sources/KeyboardShortcuts/KeyboardShortcuts.swift b/Sources/KeyboardShortcuts/KeyboardShortcuts.swift
@@ -9,12 +9,31 @@ public enum KeyboardShortcuts {
 
 	private static var registeredShortcuts = Set<Shortcut>()
 
-	// Not currently used. For the future.
-	private static var keyDownHandlers = [Shortcut: [KeyAction]]()
-	private static var keyUpHandlers = [Shortcut: [KeyAction]]()
+	private static var legacyKeyDownHandlers = [Name: [KeyAction]]()
+	private static var legacyKeyUpHandlers = [Name: [KeyAction]]()
 
-	private static var userDefaultsKeyDownHandlers = [Name: [KeyAction]]()
-	private static var userDefaultsKeyUpHandlers = [Name: [KeyAction]]()
+	private static var streamKeyDownHandlers = [Name: [UUID: KeyAction]]()
+	private static var streamKeyUpHandlers = [Name: [UUID: KeyAction]]()
+
+	private static var shortcutsForLegacyHandlers: Set<Shortcut> {
+		let shortcuts = [legacyKeyDownHandlers.keys, legacyKeyUpHandlers.keys]
+			.flatMap { $0 }
+			.compactMap(\.shortcut)
+
+		return Set(shortcuts)
+	}
+
+	private static var shortcutsForStreamHandlers: Set<Shortcut> {
+		let shortcuts = [streamKeyDownHandlers.keys, streamKeyUpHandlers.keys]
+			.flatMap { $0 }
+			.compactMap(\.shortcut)
+
+		return Set(shortcuts)
+	}
+
+	private static var shortcutsForHandlers: Set<Shortcut> {
+		shortcutsForLegacyHandlers.union(shortcutsForStreamHandlers)
+	}
 
 	/**
 	When `true`, event handlers will not be called for registered keyboard shortcuts.
@@ -35,13 +54,45 @@ public enum KeyboardShortcuts {
 		registeredShortcuts.insert(shortcut)
 	}
 
+	/**
+	Register the shortcut for the given name if it has a shortcut.
+	*/
+	private static func registerShortcutIfNeeded(for name: Name) {
+		guard let shortcut = getShortcut(for: name) else {
+			return
+		}
+
+		register(shortcut)
+	}
+
 	private static func unregister(_ shortcut: Shortcut) {
 		CarbonKeyboardShortcuts.unregister(shortcut)
 		registeredShortcuts.remove(shortcut)
 	}
 
-	// TODO: Doc comment and make this public.
-	static func unregisterAll() {
+	/**
+	Unregister the given shortcut if it has no handlers.
+	*/
+	private static func unregisterIfNeeded(_ shortcut: Shortcut) {
+		guard !shortcutsForHandlers.contains(shortcut) else {
+			return
+		}
+
+		unregister(shortcut)
+	}
+
+	/**
+	Unregister the shortcut for the given name if it has no handlers.
+	*/
+	private static func unregisterShortcutIfNeeded(for name: Name) {
+		guard let shortcut = name.shortcut else {
+			return
+		}
+
+		unregisterIfNeeded(shortcut)
+	}
+
+	private static func unregisterAll() {
 		CarbonKeyboardShortcuts.unregisterAll()
 		registeredShortcuts.removeAll()
 
@@ -52,13 +103,18 @@ public enum KeyboardShortcuts {
 	Remove all handlers receiving keyboard shortcuts events.
 
 	This can be used to reset the handlers before re-creating them to avoid having multiple handlers for the same shortcut.
+
+	- Note: This method does not affect listeners using `.on()`.
 	*/
 	public static func removeAllHandlers() {
-		CarbonKeyboardShortcuts.unregisterAll()
-		keyDownHandlers = [:]
-		keyUpHandlers = [:]
-		userDefaultsKeyDownHandlers = [:]
-		userDefaultsKeyUpHandlers = [:]
+		let shortcutsToUnregister = shortcutsForLegacyHandlers.subtracting(shortcutsForStreamHandlers)
+
+		for shortcut in shortcutsToUnregister {
+			unregister(shortcut)
+		}
+
+		legacyKeyDownHandlers = [:]
+		legacyKeyUpHandlers = [:]
 	}
 
 	// TODO: Also add `.isEnabled(_ name: Name)`.
@@ -179,18 +235,22 @@ public enum KeyboardShortcuts {
 			return
 		}
 
-		if let handlers = keyDownHandlers[shortcut] {
+		for (name, handlers) in legacyKeyDownHandlers {
+			guard getShortcut(for: name) == shortcut else {
+				continue
+			}
+
 			for handler in handlers {
 				handler()
 			}
 		}
 
-		for (name, handlers) in userDefaultsKeyDownHandlers {
+		for (name, handlers) in streamKeyDownHandlers {
 			guard getShortcut(for: name) == shortcut else {
 				continue
 			}
 
-			for handler in handlers {
+			for handler in handlers.values {
 				handler()
 			}
 		}
@@ -201,18 +261,22 @@ public enum KeyboardShortcuts {
 			return
 		}
 
-		if let handlers = keyUpHandlers[shortcut] {
+		for (name, handlers) in legacyKeyUpHandlers {
+			guard getShortcut(for: name) == shortcut else {
+				continue
+			}
+
 			for handler in handlers {
 				handler()
 			}
 		}
 
-		for (name, handlers) in userDefaultsKeyUpHandlers {
+		for (name, handlers) in streamKeyUpHandlers {
 			guard getShortcut(for: name) == shortcut else {
 				continue
 			}
 
-			for handler in handlers {
+			for handler in handlers.values {
 				handler()
 			}
 		}
@@ -240,16 +304,8 @@ public enum KeyboardShortcuts {
 	```
 	*/
 	public static func onKeyDown(for name: Name, action: @escaping KeyAction) {
-		if userDefaultsKeyDownHandlers[name] == nil {
-			userDefaultsKeyDownHandlers[name] = []
-		}
-
-		userDefaultsKeyDownHandlers[name]?.append(action)
-
-		// If the keyboard shortcut already exist, we register it.
-		if let shortcut = getShortcut(for: name) {
-			register(shortcut)
-		}
+		legacyKeyDownHandlers[name, default: []].append(action)
+		registerShortcutIfNeeded(for: name)
 	}
 
 	/**
@@ -274,16 +330,8 @@ public enum KeyboardShortcuts {
 	```
 	*/
 	public static func onKeyUp(for name: Name, action: @escaping KeyAction) {
-		if userDefaultsKeyUpHandlers[name] == nil {
-			userDefaultsKeyUpHandlers[name] = []
-		}
-
-		userDefaultsKeyUpHandlers[name]?.append(action)
-
-		// If the keyboard shortcut already exist, we register it.
-		if let shortcut = getShortcut(for: name) {
-			register(shortcut)
-		}
+		legacyKeyUpHandlers[name, default: []].append(action)
+		registerShortcutIfNeeded(for: name)
 	}
 
 	private static let userDefaultsPrefix = "KeyboardShortcuts_"
@@ -325,6 +373,74 @@ public enum KeyboardShortcuts {
 	}
 }
 
+extension KeyboardShortcuts {
+	@available(macOS 10.15, *)
+	public enum EventType {
+		case keyDown
+		case keyUp
+	}
+
+	/**
+	Listen to the keyboard shortcut with the given name being pressed.
+
+	You can register multiple listeners.
+
+	You can safely call this even if the user has not yet set a keyboard shortcut. It will just be inactive until they do.
+
+	Ending the async sequence will stop the listener. For example, in the below example, the listener will stop when the view disappears.
+
+	```
+	import SwiftUI
+	import KeyboardShortcuts
+
+	struct ContentView: View {
+		@State private var isUnicornMode = false
+
+		var body: some View {
+			Text(isUnicornMode ? "🦄" : "🐴")
+				.task {
+					for await _ in KeyboardShortcuts.on(.keyUp, for: .toggleUnicornMode) {
+						isUnicornMode.toggle()
+					}
+				}
+		}
+	}
+	```
+
+	- Note: This method is not affected by `.removeAllHandlers()`.
+	*/
+	@available(macOS 10.15, *)
+	public static func on(_ type: EventType, for name: Name) -> AsyncStream<Void> {
+		AsyncStream { continuation in
+			let id = UUID()
+
+			switch type {
+			case .keyDown:
+				streamKeyDownHandlers[name, default: [:]][id] = {
+					continuation.yield()
+				}
+			case .keyUp:
+				streamKeyUpHandlers[name, default: [:]][id] = {
+					continuation.yield()
+				}
+			}
+
+			registerShortcutIfNeeded(for: name)
+
+			continuation.onTermination = { _ in
+				switch type {
+				case .keyDown:
+					streamKeyDownHandlers[name]?[id] = nil
+				case .keyUp:
+					streamKeyUpHandlers[name]?[id] = nil
+				}
+
+				unregisterShortcutIfNeeded(for: name)
+			}
+		}
+	}
+}
+
 extension Notification.Name {
 	static let shortcutByNameDidChange = Self("KeyboardShortcuts_shortcutByNameDidChange")
 }
diff --git a/Sources/KeyboardShortcuts/NSMenuItem++.swift b/Sources/KeyboardShortcuts/NSMenuItem++.swift
@@ -53,7 +53,7 @@ extension NSMenuItem {
 
 		set()
 
-		// TODO: Use Combine when targeting macOS 10.15.
+		// TODO: Use AsyncStream when targeting macOS 10.15.
 		AssociatedKeys.observer[self] = NotificationCenter.default.addObserver(forName: .shortcutByNameDidChange, object: nil, queue: nil) { notification in
 			guard
 				let nameInNotification = notification.userInfo?["name"] as? KeyboardShortcuts.Name,