Peek a file using command line and named pipe. (#26422) (#38754)

This is a PoC. It adds the ability to peek a file using a named pipe and
a command line.

Usage/testing before this gets merged and released:

1. Build release configuration of Peek.UI and Peek.CLI.
2. Terminate PowerToys.Peek.UI.exe if running.
3. Back up and replace PowerToys.Peek.UI[.dll;.exe;.pdb;.pri]. Use
[Everything](https://www.voidtools.com/downloads/) to find the source
and destination folders.
4. Call `PowerToys.Peek.CLI.exe <path>` or send the path to peek to the
`PeekPipe` named pipe.

If this solution is OK, documentation and installer need to be updated
and a follow-up issue needs to be filed to support navigation.

---------

Co-authored-by: Clint Rutkas <clint@rutkas.com>
Co-authored-by: Leilei Zhang <leilzh@microsoft.com>
Co-authored-by: Gordon Lam (SH) <yeelam@microsoft.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

src/modules/peek/Peek.UI/MainWindowViewModel.cs

@@ -62,6 +62,12 @@ namespace Peek.UI
         [ObservableProperty]
         private IFileSystemItem? _currentItem;
 
+        /// <summary>
+        /// Work around missing navigation when peeking from CLI.
+        /// TODO: Implement navigation when peeking from CLI.
+        /// </summary>
+        private bool _isFromCli;
+
         partial void OnCurrentItemChanged(IFileSystemItem? value)
         {
             WindowTitle = value != null
@@ -129,7 +135,24 @@ namespace Peek.UI
             NavigationThrottleTimer.Interval = TimeSpan.FromMilliseconds(NavigationThrottleDelayMs);
         }
 
-        public void Initialize(HWND foregroundWindowHandle)
+        public void Initialize(SelectedItem selectedItem)
+        {
+            switch (selectedItem)
+            {
+                case SelectedItemByPath selectedItemByPath:
+                    InitializeFromCli(selectedItemByPath.Path);
+                    break;
+
+                case SelectedItemByWindowHandle selectedItemByWindowHandle:
+                    InitializeFromExplorer(selectedItemByWindowHandle.WindowHandle);
+                    break;
+
+                default:
+                    throw new NotImplementedException($"Invalid type of selected item: '{selectedItem.GetType().FullName}'");
+            }
+        }
+
+        private void InitializeFromExplorer(HWND foregroundWindowHandle)
         {
             try
             {
@@ -141,10 +164,20 @@ namespace Peek.UI
             }
 
             _currentIndex = DisplayIndex = 0;
+            _isFromCli = false;
 
             CurrentItem = (Items != null && Items.Count > 0) ? Items[0] : null;
         }
 
+        private void InitializeFromCli(string path)
+        {
+            // TODO: implement navigation
+            _isFromCli = true;
+            Items = null;
+            _currentIndex = DisplayIndex = 0;
+            CurrentItem = new FileItem(path, Path.GetFileName(path));
+        }
+
         public void Uninitialize()
         {
             _currentIndex = DisplayIndex = 0;
@@ -153,6 +186,7 @@ namespace Peek.UI
             Items = null;
             _navigationDirection = NavigationDirection.Forwards;
             IsErrorVisible = false;
+            _isFromCli = false;
         }
 
         public void AttemptPreviousNavigation() => Navigate(NavigationDirection.Backwards);
@@ -166,6 +200,12 @@ namespace Peek.UI
                 return;
             }
 
+            // TODO: implement navigation.
+            if (_isFromCli)
+            {
+                return;
+            }
+
             if (Items == null || Items.Count == _deletedItemIndexes.Count)
             {
                 _currentIndex = DisplayIndex = 0;

src/modules/peek/Peek.UI/Models/SelectedItem.cs

@@ -0,0 +1,11 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Peek.UI.Models
+{
+    public abstract class SelectedItem
+    {
+        public abstract bool Matches(string? path);
+    }
+}

src/modules/peek/Peek.UI/Models/SelectedItemByPath.cs

@@ -0,0 +1,23 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+
+namespace Peek.UI.Models
+{
+    public class SelectedItemByPath : SelectedItem
+    {
+        public string Path { get; }
+
+        public SelectedItemByPath(string path)
+        {
+            Path = path;
+        }
+
+        public override bool Matches(string? path)
+        {
+            return string.Equals(Path, path, StringComparison.OrdinalIgnoreCase);
+        }
+    }
+}

src/modules/peek/Peek.UI/Models/SelectedItemByWindowHandle.cs

@@ -0,0 +1,34 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Peek.UI.Extensions;
+using Peek.UI.Helpers;
+using Windows.Win32.Foundation;
+
+namespace Peek.UI.Models
+{
+    public class SelectedItemByWindowHandle : SelectedItem
+    {
+        public HWND WindowHandle { get; }
+
+        public SelectedItemByWindowHandle(HWND windowHandle)
+        {
+            WindowHandle = windowHandle;
+        }
+
+        public override bool Matches(string? path)
+        {
+            var selectedItems = FileExplorerHelper.GetSelectedItems(WindowHandle);
+            var selectedItemsCount = selectedItems?.GetCount() ?? 0;
+            if (selectedItems == null || selectedItemsCount == 0 || selectedItemsCount > 1)
+            {
+                return false;
+            }
+
+            var fileExplorerSelectedItemPath = selectedItems.GetItemAt(0).ToIFileSystemItem().Path;
+            var currentItemPath = path;
+            return fileExplorerSelectedItemPath != null && currentItemPath != null && fileExplorerSelectedItemPath != currentItemPath;
+        }
+    }
+}

src/modules/peek/Peek.UI/PeekXAML/App.xaml.cs

@@ -3,16 +3,19 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-
+using System.IO;
+using System.Threading;
 using ManagedCommon;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using Microsoft.PowerToys.Telemetry;
 using Microsoft.UI.Xaml;
+using Microsoft.UI.Xaml.Controls.Primitives;
 using Peek.Common;
 using Peek.FilePreviewer;
 using Peek.FilePreviewer.Models;
 using Peek.FilePreviewer.Previewers;
+using Peek.UI.Models;
 using Peek.UI.Native;
 using Peek.UI.Telemetry.Events;
 using Peek.UI.Views;
@@ -23,7 +26,7 @@ namespace Peek.UI
     /// <summary>
     /// Provides application-specific behavior to supplement the default Application class.
     /// </summary>
-    public partial class App : Application, IApp
+    public partial class App : Application, IApp, IDisposable
     {
         public static int PowerToysPID { get; set; }
 
@@ -36,6 +39,10 @@ namespace Peek.UI
 
         private MainWindow? Window { get; set; }
 
+        private bool _disposed;
+        private SelectedItem? _selectedItem;
+        private bool _launchedFromCli;
+
         /// <summary>
         /// Initializes a new instance of the <see cref="App"/> class.
         /// Initializes the singleton application object.  This is the first line of authored code
@@ -52,22 +59,22 @@ namespace Peek.UI
             InitializeComponent();
             Logger.InitializeLogger("\\Peek\\Logs");
 
-            Host = Microsoft.Extensions.Hosting.Host.
-            CreateDefaultBuilder().
-            UseContentRoot(AppContext.BaseDirectory).
-            ConfigureServices((context, services) =>
-            {
-                // Core Services
-                services.AddTransient<NeighboringItemsQuery>();
-                services.AddSingleton<IUserSettings, UserSettings>();
-                services.AddSingleton<IPreviewSettings, PreviewSettings>();
+            Host = Microsoft.Extensions.Hosting.Host
+                .CreateDefaultBuilder()
+                .UseContentRoot(AppContext.BaseDirectory)
+                .ConfigureServices((context, services) =>
+                {
+                    // Core Services
+                    services.AddTransient<NeighboringItemsQuery>();
+                    services.AddSingleton<IUserSettings, UserSettings>();
+                    services.AddSingleton<IPreviewSettings, PreviewSettings>();
 
-                // Views and ViewModels
-                services.AddTransient<TitleBar>();
-                services.AddTransient<FilePreview>();
-                services.AddTransient<MainWindowViewModel>();
-            }).
-            Build();
+                    // Views and ViewModels
+                    services.AddTransient<TitleBar>();
+                    services.AddTransient<FilePreview>();
+                    services.AddTransient<MainWindowViewModel>();
+                })
+                .Build();
 
             UnhandledException += App_UnhandledException;
         }
@@ -99,6 +106,7 @@ namespace Peek.UI
             var cmdArgs = Environment.GetCommandLineArgs();
             if (cmdArgs?.Length > 1)
             {
+                // Check if the last argument is a PowerToys Runner PID
                 if (int.TryParse(cmdArgs[^1], out int powerToysRunnerPid))
                 {
                     RunnerHelper.WaitForPowerToysRunner(powerToysRunnerPid, () =>
@@ -107,9 +115,25 @@ namespace Peek.UI
                         Environment.Exit(0);
                     });
                 }
+                else
+                {
+                    // Command line argument is a file path - activate Peek with that file
+                    string filePath = cmdArgs[^1];
+                    if (File.Exists(filePath) || Directory.Exists(filePath))
+                    {
+                        _selectedItem = new SelectedItemByPath(filePath);
+                        _launchedFromCli = true;
+                        OnShowPeek();
+                        return;
+                    }
+                    else
+                    {
+                        Logger.LogError($"Command line argument is not a valid file or directory: {filePath}");
+                    }
+                }
             }
 
-            NativeEventWaiter.WaitForEventLoop(Constants.ShowPeekEvent(), OnPeekHotkey);
+            NativeEventWaiter.WaitForEventLoop(Constants.ShowPeekEvent(), OnShowPeek);
             NativeEventWaiter.WaitForEventLoop(Constants.TerminatePeekEvent(), () =>
             {
                 ShellPreviewHandlerPreviewer.ReleaseHandlerFactories();
@@ -126,11 +150,16 @@ namespace Peek.UI
         /// <summary>
         /// Handle Peek hotkey
         /// </summary>
-        private void OnPeekHotkey()
+        private void OnShowPeek()
         {
-            // Need to read the foreground HWND before activating Peek to avoid focus stealing
-            // Foreground HWND must always be Explorer or Desktop
-            var foregroundWindowHandle = Windows.Win32.PInvoke_PeekUI.GetForegroundWindow();
+            // null means explorer, not null means CLI
+            if (_selectedItem == null)
+            {
+                // Need to read the foreground HWND before activating Peek to avoid focus stealing
+                // Foreground HWND must always be Explorer or Desktop
+                var foregroundWindowHandle = Windows.Win32.PInvoke_PeekUI.GetForegroundWindow();
+                _selectedItem = new SelectedItemByWindowHandle(foregroundWindowHandle);
+            }
 
             bool firstActivation = false;
 
@@ -140,7 +169,38 @@ namespace Peek.UI
                 Window = new MainWindow();
             }
 
-            Window.Toggle(firstActivation, foregroundWindowHandle);
+            Window.Toggle(firstActivation, _selectedItem, _launchedFromCli);
+            _launchedFromCli = false;
+            _selectedItem = null;
+        }
+
+        protected virtual void Dispose(bool disposing)
+        {
+            if (!_disposed)
+            {
+                if (disposing)
+                {
+                    // dispose managed state (managed objects)
+                }
+
+                // free unmanaged resources (unmanaged objects) and override finalizer
+                // set large fields to null
+                _disposed = true;
+            }
+        }
+
+        /* // override finalizer only if 'Dispose(bool disposing)' has code to free unmanaged resources
+        // ~App()
+        // {
+        //     // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
+        //     Dispose(disposing: false);
+        // } */
+
+        public void Dispose()
+        {
+            // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
+            Dispose(disposing: true);
+            GC.SuppressFinalize(this);
         }
     }
 }

src/modules/peek/Peek.UI/PeekXAML/MainWindow.xaml.cs

@@ -18,6 +18,7 @@ using Peek.FilePreviewer.Models;
 using Peek.FilePreviewer.Previewers;
 using Peek.UI.Extensions;
 using Peek.UI.Helpers;
+using Peek.UI.Models;
 using Peek.UI.Telemetry.Events;
 using Windows.Foundation;
 using WinUIEx;
@@ -38,6 +39,7 @@ namespace Peek.UI
         /// dialog is open at a time.
         /// </summary>
         private bool _isDeleteInProgress;
+        private bool _exitAfterClose;
 
         public MainWindow()
         {
@@ -116,12 +118,17 @@ namespace Peek.UI
         /// <summary>
         /// Toggling the window visibility and querying files when necessary.
         /// </summary>
-        public void Toggle(bool firstActivation, Windows.Win32.Foundation.HWND foregroundWindowHandle)
+        public void Toggle(bool firstActivation, SelectedItem selectedItem, bool exitAfterClose)
         {
+            if (exitAfterClose)
+            {
+                _exitAfterClose = true;
+            }
+
             if (firstActivation)
             {
                 Activate();
-                Initialize(foregroundWindowHandle);
+                Initialize(selectedItem);
                 return;
             }
 
@@ -132,9 +139,9 @@ namespace Peek.UI
 
             if (AppWindow.IsVisible)
             {
-                if (IsNewSingleSelectedItem(foregroundWindowHandle))
+                if (IsNewSingleSelectedItem(selectedItem))
                 {
-                    Initialize(foregroundWindowHandle);
+                    Initialize(selectedItem);
                     Activate(); // Brings existing window into focus in case it was previously minimized
                 }
                 else
@@ -144,7 +151,7 @@ namespace Peek.UI
             }
             else
             {
-                Initialize(foregroundWindowHandle);
+                Initialize(selectedItem);
             }
         }
 
@@ -182,12 +189,12 @@ namespace Peek.UI
             Uninitialize();
         }
 
-        private void Initialize(Windows.Win32.Foundation.HWND foregroundWindowHandle)
+        private void Initialize(SelectedItem selectedItem)
         {
             var bootTime = new System.Diagnostics.Stopwatch();
             bootTime.Start();
 
-            ViewModel.Initialize(foregroundWindowHandle);
+            ViewModel.Initialize(selectedItem);
             ViewModel.ScalingFactor = this.GetMonitorScale();
             this.Content.KeyUp += Content_KeyUp;
 
@@ -207,6 +214,11 @@ namespace Peek.UI
             this.Content.KeyUp -= Content_KeyUp;
 
             ShellPreviewHandlerPreviewer.ReleaseHandlerFactories();
+
+            if (_exitAfterClose)
+            {
+                Environment.Exit(0);
+            }
         }
 
         /// <summary>
@@ -272,20 +284,11 @@ namespace Peek.UI
             Uninitialize();
         }
 
-        private bool IsNewSingleSelectedItem(Windows.Win32.Foundation.HWND foregroundWindowHandle)
+        private bool IsNewSingleSelectedItem(SelectedItem selectedItem)
         {
             try
             {
-                var selectedItems = FileExplorerHelper.GetSelectedItems(foregroundWindowHandle);
-                var selectedItemsCount = selectedItems?.GetCount() ?? 0;
-                if (selectedItems == null || selectedItemsCount == 0 || selectedItemsCount > 1)
-                {
-                    return false;
-                }
-
-                var fileExplorerSelectedItemPath = selectedItems.GetItemAt(0).ToIFileSystemItem().Path;
-                var currentItemPath = ViewModel.CurrentItem?.Path;
-                return fileExplorerSelectedItemPath != null && currentItemPath != null && fileExplorerSelectedItemPath != currentItemPath;
+                return selectedItem.Matches(ViewModel.CurrentItem?.Path);
             }
             catch (Exception ex)
             {