feat: make system calls more parallel (closes #160)

alt-tab-macos/api-wrappers/HelperExtensions.swift

@@ -107,3 +107,18 @@ extension NSGridView {
         }
     }
 }
+
+extension Array {
+    // forEach with each iteration run concurrently on the global queue
+    func forEachAsync(fn: @escaping (Element) -> Void) {
+        let group = DispatchGroup()
+        for element in self {
+            group.enter()
+            DispatchQueue.global(qos: .userInteractive).async(group: group) {
+                fn(element)
+                group.leave()
+            }
+        }
+        group.wait()
+    }
+}

alt-tab-macos/logic/Windows.swift

@@ -26,17 +26,16 @@ class Windows {
 
     static func updateSpaces() {
         let spacesMap = Spaces.allIdsAndIndexes()
-        for window in list {
+        list.forEachAsync { window in
             let spaceIds = window.cgWindowId.spaces()
-            guard spaceIds.count > 0 else { continue }
-            if spaceIds.count > 1 {
+            if spaceIds.count == 1 {
+                window.spaceId = spaceIds.first!
+                window.spaceIndex = spacesMap.first { $0.0 == spaceIds.first! }!.1
+            } else if spaceIds.count > 1 {
                 window.spaceId = Spaces.currentSpaceId
                 window.spaceIndex = Spaces.currentSpaceIndex
                 window.isOnAllSpaces = true
-                continue
             }
-            window.spaceId = spaceIds.first!
-            window.spaceIndex = spacesMap.first { $0.0 == spaceIds.first! }!.1
         }
     }
 
@@ -59,7 +58,7 @@ class Windows {
     }
 
     static func refreshAllThumbnails() {
-        for window in list {
+        list.forEachAsync { window in
             window.refreshThumbnail()
         }
     }