Support multi-user scenario

LinearMouse/AppDelegate.swift

@@ -7,9 +7,12 @@
 
 import Combine
 import SwiftUI
+import os.log
 
 @main
 class AppDelegate: NSObject, NSApplicationDelegate {
+    private static let log = OSLog(subsystem: Bundle.main.bundleIdentifier!, category: "AppDelegate")
+
     private let autoUpdateManager = AutoUpdateManager.shared
     private let statusItem = StatusItem.shared
     private var defaultsSubscription: AnyCancellable!
@@ -33,6 +36,28 @@ class AppDelegate: NSObject, NSApplicationDelegate {
                 }
             }
             self.update(defaults)
+
+            NSWorkspace.shared.notificationCenter.addObserver(forName: NSWorkspace.sessionDidResignActiveNotification, object: nil,
+                                                              queue: nil, using: { _ in
+                DispatchQueue.main.async {
+                    os_log("Session inactive", log: Self.log, type: .debug)
+                    if let eventTap = self.eventTap {
+                        eventTap.disable()
+                    }
+                    DeviceManager.shared.pause()
+                }
+            })
+
+            NSWorkspace.shared.notificationCenter.addObserver(forName: NSWorkspace.sessionDidBecomeActiveNotification, object: nil,
+                                                              queue: nil, using: { _ in
+                DispatchQueue.main.async {
+                    os_log("Session active", log: Self.log, type: .debug)
+                    if let eventTap = self.eventTap {
+                        eventTap.enable()
+                    }
+                    DeviceManager.shared.resume()
+                }
+            })
         }
     }
 
@@ -60,6 +85,6 @@ class AppDelegate: NSObject, NSApplicationDelegate {
     }
 
     func applicationWillTerminate(_ notification: Notification) {
-        DeviceManager.shared.restorePointerSpeedToInitialValue()
+        DeviceManager.shared.pause()
     }
 }

LinearMouse/Device/DeviceManager.swift

@@ -13,6 +13,7 @@ class DeviceManager {
 
     private static let log = OSLog(subsystem: Bundle.main.bundleIdentifier!, category: "DeviceManager")
 
+    private var paused = false
     private let eventSystemClient = IOHIDEventSystemClientCreate(kCFAllocatorDefault).takeRetainedValue()
     private var devices = Set<Device>()
 
@@ -35,6 +36,17 @@ class DeviceManager {
         IOHIDEventSystemClientScheduleWithDispatchQueue(eventSystemClient, DispatchQueue.main)
     }
 
+    func pause() {
+        restorePointerSpeedToInitialValue()
+        paused = true
+    }
+
+    func resume() {
+        paused = false
+        discoverServiceClients()
+        renewPointerSpeed()
+    }
+
     private func setupServiceClients() {
         let usageMouse = [
             kIOHIDDeviceUsagePageKey: kHIDPage_GenericDesktop,
@@ -55,6 +67,10 @@ class DeviceManager {
                 }
             }
         }, nil, nil)
+        discoverServiceClients()
+    }
+
+    private func discoverServiceClients() {
         let serviceClients = IOHIDEventSystemClientCopyServices(eventSystemClient) as! [IOHIDServiceClient]
         for serviceClient in serviceClients {
             add(serviceClient: serviceClient)
@@ -109,6 +125,9 @@ class DeviceManager {
     }
 
     func renewPointerSpeed() {
+        guard !self.paused else {
+            return
+        }
         if let acceleration = lastPointerAcceleration,
            let sensitivity = lastPointerSensitivity,
            let disableAcceleration = lastDisablePointerAcceleration {
@@ -117,6 +136,9 @@ class DeviceManager {
     }
 
     func renewPointerSpeed(forDevice device: Device) {
+        guard !self.paused else {
+            return
+        }
         if let acceleration = lastPointerAcceleration,
            let sensitivity = lastPointerSensitivity,
            let disableAcceleration = lastDisablePointerAcceleration {