perf: cache screen uuids and frontmost app

src/logic/Applications.swift

@@ -3,6 +3,7 @@ import ApplicationServices
 
 class Applications {
     static var list = [Application]()
+    static var frontmostPid = NSWorkspace.shared.frontmostApplication?.processIdentifier
 
     static func initialDiscovery() {
         addInitialRunningApplications()

src/logic/Screens.swift

@@ -5,8 +5,9 @@ class Screens {
 
     static func refresh() {
         all.removeAll()
+        NSScreen.clearUuidCache()
         for screen in NSScreen.screens {
-            guard let uuid = screen.uuid() else { continue }
+            guard let uuid = screen.cachedUuid() else { continue }
             all[uuid] = screen
         }
     }
@@ -14,6 +15,7 @@ class Screens {
 
 extension NSScreen {
     static var preferred = NSScreen.screens.first!
+    private static var uuidCache = [ObjectIdentifier: ScreenUuid]()
 
     static func updatePreferred() {
         preferred = detectPreferred() ?? NSScreen.screens.first!
@@ -34,7 +36,7 @@ extension NSScreen {
     ///   * if NSScreen.screensHaveSeparateSpaces == false, and key window is on another screen than screens[0], it still returns screens[0]
     /// we find the screen with the key window ourselves manually
     static func active() -> NSScreen? {
-        guard let frontmostPid = NSWorkspace.shared.frontmostApplication?.processIdentifier,
+        guard let frontmostPid = Applications.frontmostPid,
               // we avoid Applications.findOrCreate() here, because it active() is called very early during launch
               // we are not ready to create applications yet
               let frontmostApp = (Applications.list.first { $0.pid == frontmostPid }) else { return nil }
@@ -47,7 +49,7 @@ extension NSScreen {
 
     /// there is only 1 active menubar. Other screens will show their menubar dimmed
     static func withActiveMenubar() -> NSScreen? {
-        return NSScreen.screens.first { CGSCopyActiveMenuBarDisplayIdentifier(CGS_CONNECTION) == $0.uuid() }
+        return NSScreen.screens.first { CGSCopyActiveMenuBarDisplayIdentifier(CGS_CONNECTION) == $0.cachedUuid() }
     }
 
     static func withMouse() -> NSScreen? {
@@ -74,6 +76,18 @@ extension NSScreen {
         return uuid
     }
 
+    static func clearUuidCache() {
+        uuidCache.removeAll(keepingCapacity: true)
+    }
+
+    func cachedUuid() -> ScreenUuid? {
+        let key = ObjectIdentifier(self)
+        if let uuid = NSScreen.uuidCache[key] { return uuid }
+        guard let uuid = uuid() else { return nil }
+        NSScreen.uuidCache[key] = uuid
+        return uuid
+    }
+
     // periphery:ignore
     func refreshRate() -> Double? {
         return number().flatMap { CGDisplayCopyDisplayMode($0)?.refreshRate }
@@ -102,4 +116,3 @@ extension NSScreen {
 }
 
 typealias ScreenUuid = CFString
-

src/logic/Window.swift

@@ -267,13 +267,13 @@ class Window {
     }
 
     private func updateScreenId() {
-        screenId = NSScreen.screens.first { isOnScreen($0) }?.uuid()
+        screenId = NSScreen.screens.first { isOnScreen($0) }?.cachedUuid()
     }
 
     /// window may not be visible on that screen (e.g. the window is not on the current Space)
     func isOnScreen(_ screen: NSScreen) -> Bool {
         if NSScreen.screensHaveSeparateSpaces {
-            if let screenUuid = screen.uuid(), let screenSpaces = Spaces.screenSpacesMap[screenUuid] {
+            if let screenUuid = screen.cachedUuid(), let screenSpaces = Spaces.screenSpacesMap[screenUuid] {
                 return screenSpaces.contains { screenSpace in spaceIds.contains { $0 == screenSpace } }
             }
         } else {

src/logic/Windows.swift

@@ -136,8 +136,8 @@ class Windows {
                         ($0.hide == .always || (window.isWindowlessApp && $0.hide != .none))
                 }
             } ?? false) &&
-            !(Preferences.appsToShow[App.app.shortcutIndex] == .active && window.application.pid != NSWorkspace.shared.frontmostApplication?.processIdentifier) &&
-            !(Preferences.appsToShow[App.app.shortcutIndex] == .nonActive && window.application.pid == NSWorkspace.shared.frontmostApplication?.processIdentifier) &&
+            !(Preferences.appsToShow[App.app.shortcutIndex] == .active && window.application.pid != Applications.frontmostPid) &&
+            !(Preferences.appsToShow[App.app.shortcutIndex] == .nonActive && window.application.pid == Applications.frontmostPid) &&
             !(!(Preferences.showHiddenWindows[App.app.shortcutIndex] != .hide) && window.isHidden) &&
             ((Preferences.showWindowlessApps[App.app.shortcutIndex] != .hide && window.isWindowlessApp) ||
                 !window.isWindowlessApp &&
@@ -191,7 +191,7 @@ class Windows {
             hoveredWindowIndex = nil
             ThumbnailsView.highlight(oldIndex)
         }
-        if let frontmostPid = NSWorkspace.shared.frontmostApplication?.processIdentifier,
+        if let frontmostPid = Applications.frontmostPid,
            let frontmostApp = Applications.findOrCreate(frontmostPid),
            (frontmostApp.focusedWindow == nil || Preferences.windowOrder[App.app.shortcutIndex] != .recentlyFocused),
            let lastFocusedOrderWindowIndex = getLastFocusedOrderWindowIndex() {

src/logic/events/AccessibilityEvents.swift

@@ -35,6 +35,7 @@ class AccessibilityEvents {
     }
 
     private static func applicationActivated(_ app: Application, _ pid: pid_t, _ type: String, _ appFocusedWindow: AXUIElement?) {
+        Applications.frontmostPid = pid
         if app.hasBeenActiveOnce != true {
             app.hasBeenActiveOnce = true
         }

src/logic/events/ScreensEvents.swift

@@ -39,7 +39,7 @@ final class Debouncer {
             // ScreensEvents: a screen added or removed can shuffle windows around Spaces; we refresh them
             // SpacesEvents: if UI was kept open during Space transition, the Spaces may be obsolete; we refresh them
             App.app.refreshOpenUiAfterExternalEvent(Windows.list)
-            Logger.info { "screens:\(NSScreen.screens.map { ($0.uuid() ?? "nil" as CFString, $0.frame) })" }
+            Logger.info { "screens:\(NSScreen.screens.map { ($0.cachedUuid() ?? "nil" as CFString, $0.frame) })" }
             Logger.info { "currentSpace:\(Spaces.currentSpaceIndex) (id:\(Spaces.currentSpaceId)) spaces:\(Spaces.screenSpacesMap)" }
         })
         workItem = item

src/logic/events/SpacesEvents.swift

@@ -13,7 +13,7 @@ class SpacesEvents {
             // this window doesn't emit resize/move events. It doesn't pass isActualWindow on creation. It's added on focusedWindowChanged
             // for such cases, we refresh isFullscreen on Space change
             Windows.updateIsFullscreenOnCurrentSpace()
-            if let frontmostPid = NSWorkspace.shared.frontmostApplication?.processIdentifier,
+            if let frontmostPid = Applications.frontmostPid,
                let frontmostApp = Applications.findOrCreate(frontmostPid),
                let focusedWindow = frontmostApp.focusedWindow {
                 App.app.checkIfShortcutsShouldBeDisabled(focusedWindow, nil)

src/ui/App.swift

@@ -186,7 +186,7 @@ class App: AppCenterApplication {
         if let window = selectedWindow, MissionControl.state() == .inactive || MissionControl.state() == .showDesktop {
             window.focus()
             if Preferences.cursorFollowFocus == .always || (
-                Preferences.cursorFollowFocus == .differentScreen && (Spaces.screenSpacesMap.first { $0.value.contains { space in window.spaceIds.contains(space) } })?.key != NSScreen.active()?.uuid()) {
+                Preferences.cursorFollowFocus == .differentScreen && (Spaces.screenSpacesMap.first { $0.value.contains { space in window.spaceIds.contains(space) } })?.key != NSScreen.active()?.cachedUuid()) {
                 moveCursorToSelectedWindow(window)
             }
         } else {