[Run][WindowWalker]Improve EnumWindows synchronization (#27490)

src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Components/OpenWindows.cs

@@ -6,6 +6,8 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Runtime.InteropServices;
+using System.Threading;
 using Wox.Plugin.Common.Win32;
 
 namespace Microsoft.Plugin.WindowWalker.Components
@@ -15,6 +17,11 @@ namespace Microsoft.Plugin.WindowWalker.Components
     /// </summary>
     internal class OpenWindows
     {
+        /// <summary>
+        /// Used to enforce single execution of EnumWindows
+        /// </summary>
+        private static readonly object _enumWindowsLock = new();
+
         /// <summary>
         /// PowerLauncher main executable
         /// </summary>
@@ -33,10 +40,7 @@ namespace Microsoft.Plugin.WindowWalker.Components
         /// <summary>
         /// Gets the list of all open windows
         /// </summary>
-        internal List<Window> Windows
+        internal List<Window> Windows => windows;
-        {
-            get { return new List<Window>(windows); }
-        }
 
         /// <summary>
         /// Gets an instance property of this class that makes sure that
@@ -68,11 +72,26 @@ namespace Microsoft.Plugin.WindowWalker.Components
         /// <summary>
         /// Updates the list of open windows
         /// </summary>
-        internal void UpdateOpenWindowsList()
+        internal void UpdateOpenWindowsList(CancellationToken cancellationToken)
         {
-            windows.Clear();
+            var tokenHandle = GCHandle.Alloc(cancellationToken);
-            EnumWindowsProc callbackptr = new EnumWindowsProc(WindowEnumerationCallBack);
+            try
-            _ = NativeMethods.EnumWindows(callbackptr, 0);
+            {
+                var tokenHandleParam = GCHandle.ToIntPtr(tokenHandle);
+                lock (_enumWindowsLock)
+                {
+                    windows.Clear();
+                    EnumWindowsProc callbackptr = new EnumWindowsProc(WindowEnumerationCallBack);
+                    _ = NativeMethods.EnumWindows(callbackptr, tokenHandleParam);
+                }
+            }
+            finally
+            {
+                if (tokenHandle.IsAllocated)
+                {
+                    tokenHandle.Free();
+                }
+            }
         }
 
         /// <summary>
@@ -84,6 +103,14 @@ namespace Microsoft.Plugin.WindowWalker.Components
         /// <returns>true to make sure to continue enumeration</returns>
         internal bool WindowEnumerationCallBack(IntPtr hwnd, IntPtr lParam)
         {
+            var tokenHandle = GCHandle.FromIntPtr(lParam);
+            var cancellationToken = (CancellationToken)tokenHandle.Target;
+            if (cancellationToken.IsCancellationRequested)
+            {
+                // Stop enumeration
+                return false;
+            }
+
             Window newWindow = new Window(hwnd);
 
             if (newWindow.IsWindow && newWindow.Visible && newWindow.IsOwner &&

src/modules/launcher/Plugins/Microsoft.Plugin.WindowWalker/Main.cs

@@ -4,6 +4,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Threading;
 using System.Windows.Controls;
 using ManagedCommon;
 using Microsoft.Plugin.WindowWalker.Components;
@@ -13,8 +14,11 @@ using Wox.Plugin.Common.VirtualDesktop.Helper;
 
 namespace Microsoft.Plugin.WindowWalker
 {
-    public class Main : IPlugin, IPluginI18n, ISettingProvider, IContextMenu
+    public class Main : IPlugin, IPluginI18n, ISettingProvider, IContextMenu, IDisposable
     {
+        private CancellationTokenSource _cancellationTokenSource = new();
+        private bool _disposed;
+
         private string IconPath { get; set; }
 
         private string InfoIconPath { get; set; }
@@ -27,11 +31,6 @@ namespace Microsoft.Plugin.WindowWalker
 
         internal static readonly VirtualDesktopHelper VirtualDesktopHelperInstance = new VirtualDesktopHelper();
 
-        static Main()
-        {
-            OpenWindows.Instance.UpdateOpenWindowsList();
-        }
-
         public List<Result> Query(Query query)
         {
             if (query == null)
@@ -39,8 +38,12 @@ namespace Microsoft.Plugin.WindowWalker
                 throw new ArgumentNullException(nameof(query));
             }
 
+            _cancellationTokenSource?.Cancel();
+            _cancellationTokenSource?.Dispose();
+            _cancellationTokenSource = new CancellationTokenSource();
+
             VirtualDesktopHelperInstance.UpdateDesktopList();
-            OpenWindows.Instance.UpdateOpenWindowsList();
+            OpenWindows.Instance.UpdateOpenWindowsList(_cancellationTokenSource.Token);
             SearchController.Instance.UpdateSearchText(query.Search);
             List<SearchResult> searchControllerResults = SearchController.Instance.SearchMatches;
 
@@ -103,5 +106,23 @@ namespace Microsoft.Plugin.WindowWalker
         {
             WindowWalkerSettings.Instance.UpdateSettings(settings);
         }
+
+        public void Dispose()
+        {
+            Dispose(disposing: true);
+            GC.SuppressFinalize(this);
+        }
+
+        protected virtual void Dispose(bool disposing)
+        {
+            if (!_disposed)
+            {
+                if (disposing)
+                {
+                    _cancellationTokenSource?.Dispose();
+                    _disposed = true;
+                }
+            }
+        }
     }
 }

src/modules/launcher/Wox.Plugin/Common/Win32/NativeMethods.cs

@@ -16,7 +16,7 @@ namespace Wox.Plugin.Common.Win32
     public static class NativeMethods
     {
         [DllImport("user32.dll", CharSet = CharSet.Unicode)]
-        public static extern int EnumWindows(EnumWindowsProc callPtr, int lPar);
+        public static extern int EnumWindows(EnumWindowsProc callPtr, IntPtr lParam);
 
         [DllImport("user32.dll", SetLastError = true)]
         public static extern IntPtr GetWindow(IntPtr hWnd, GetWindowCmd uCmd);