Extract a per-user background host so indexing can later run outside the window.

Keep the GUI as the index writer for now; mutex, named pipe, and opt-in logon autostart prepare Explorer.Host.exe without two SQLite writers.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/Explorer.App/AppServices.cs

@@ -1,21 +1,11 @@
-using Explorer.Analysis;
 using Explorer.Application;
-using Explorer.Domain;
 using Explorer.Domain.Abstractions;
-using Explorer.FileOperations;
-using Explorer.Indexing;
-using Explorer.Plugin.Abstractions;
-using Explorer.Plugin.GoogleDrive;
-using Explorer.Plugin.Nextcloud;
-using Explorer.Plugin.OneDrive;
+using Explorer.Hosting;
 using Explorer.Presentation;
 using Explorer.Presentation.ViewModels;
-using Explorer.Search;
-using Explorer.Storage.Sqlite;
 using Explorer.Windows;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
-using Microsoft.Extensions.Logging;
 
 namespace Explorer.App;
 
@@ -23,105 +13,20 @@ public static class AppServices
 {
     public static IServiceCollection AddExplorer(this IServiceCollection services)
     {
-        services.AddSingleton<IClock, SystemClock>();
-        services.AddSingleton<IAppEnvironment, WindowsAppEnvironment>();
-        services.AddSingleton<IVolumeService, WindowsVolumeService>();
-        services.AddSingleton<IFileSystemEnumerator, WindowsFileSystemEnumerator>();
-        services.AddSingleton<IUsnJournal, WindowsUsnJournal>();
-        services.AddSingleton<IShellFileOperations, WindowsShellFileOperations>();
+        services.AddExplorerCore();
+        services.AddExplorerUi();
+        return services;
+    }
+
+    public static IServiceCollection AddExplorerUi(this IServiceCollection services)
+    {
         services.AddSingleton<IOsClipboard, Services.WpfClipboard>();
-        services.AddSingleton<IIndexStore>(sp =>
-        {
-            var env = sp.GetRequiredService<IAppEnvironment>();
-            var logger = sp.GetRequiredService<ILogger<SqliteIndexStore>>();
-            return new SqliteIndexStore(env.DatabasePath, logger);
-        });
-        services.AddSingleton<IStorageProvider, OneDriveStorageProvider>();
-        services.AddSingleton<IStorageProvider, GoogleDriveStorageProvider>();
-        services.AddSingleton<IStorageProvider, NextcloudStorageProvider>();
-        services.AddSingleton<StorageProviderRegistry>();
-        services.AddSingleton<IHydrationGuard, HydrationGuard>();
-        services.AddSingleton<IArchiveExecutor, SevenZipArchiveExecutor>();
-        services.AddSingleton<WindowsGitStatusProvider>();
-        services.AddSingleton<IGitStatusProvider>(sp => sp.GetRequiredService<WindowsGitStatusProvider>());
-        services.AddSingleton<IGitCommandProvider>(sp => sp.GetRequiredService<WindowsGitStatusProvider>());
         services.AddSingleton<IWorkspaceLauncher, WindowsWorkspaceLauncher>();
-        services.AddSingleton<IElevatedScanService, WindowsElevatedScanService>();
-        services.AddSingleton<IRecycleBinCatalog, WindowsRecycleBinCatalog>();
-        services.AddSingleton<SourceManager>();
-        services.AddSingleton<PathHistoryStore>();
-        services.AddSingleton<CloudPlaceStore>();
-        services.AddSingleton<UiPreferencesStore>();
-        services.AddSingleton<IArchiveCatalog, ArchiveCatalog>();
-        services.AddSingleton<ArchiveContentsIndexer>();
-        services.AddSingleton<BrowseService>();
         services.AddSingleton<ThumbnailService>();
         services.AddSingleton<IThumbnailService>(sp => sp.GetRequiredService<ThumbnailService>());
-        services.AddSingleton<FilesystemScanner>();
-        services.AddSingleton<FolderReconciler>();
-        services.AddSingleton<UsnChangeApplier>();
-        services.AddSingleton<IndexingCoordinator>();
-        services.AddSingleton<DirectoryWatcherHub>();
-        services.AddSingleton<SearchService>();
-        services.AddSingleton<AnalysisService>();
-        services.AddSingleton<IOperationExecutor, NativeFileOperationExecutor>();
-        services.AddSingleton<TransferQueue>();
-        services.AddSingleton<FileOperationService>();
-        services.AddSingleton<RenamePlanner>();
-        services.AddSingleton<RenameBatchService>();
-        services.AddSingleton<FolderSyncPlanner>();
-        services.AddSingleton<FolderSyncService>();
-        services.AddSingleton<FileOperationProfilePlanner>();
-        services.AddSingleton<OperationProfileService>();
-        services.AddSingleton<ReorganizePlanner>();
-        services.AddSingleton<ReorganizeService>();
-        services.AddSingleton<DuplicateHashWorker>();
-        services.AddSingleton<HistoryRollupService>();
         services.AddSingleton<MainViewModel>();
         services.AddSingleton<MainWindow>();
-        services.AddHostedService(sp => sp.GetRequiredService<IndexingCoordinator>());
-        services.AddHostedService(sp => sp.GetRequiredService<TransferQueue>());
-        services.AddHostedService(sp => sp.GetRequiredService<DuplicateHashWorker>());
-        services.AddHostedService(sp => sp.GetRequiredService<HistoryRollupService>());
         services.AddHostedService(sp => sp.GetRequiredService<ThumbnailService>());
-        services.AddHostedService<WatcherHostedService>();
         return services;
     }
 }
-
-public sealed class WatcherHostedService : BackgroundService
-{
-    private readonly DirectoryWatcherHub _hub;
-    private readonly SourceManager _sources;
-    private readonly TransferQueue _transfers;
-    private readonly FolderSyncService _sync;
-    private readonly OperationProfileService _profiles;
-
-    public WatcherHostedService(
-        DirectoryWatcherHub hub,
-        SourceManager sources,
-        TransferQueue transfers,
-        FolderSyncService sync,
-        OperationProfileService profiles)
-    {
-        _hub = hub;
-        _sources = sources;
-        _transfers = transfers;
-        _sync = sync;
-        _profiles = profiles;
-    }
-
-    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
-    {
-        using var timer = new PeriodicTimer(TimeSpan.FromSeconds(20));
-        await _hub.RefreshAsync(stoppingToken).ConfigureAwait(false);
-        while (await timer.WaitForNextTickAsync(stoppingToken).ConfigureAwait(false))
-        {
-            await _sources.RefreshOnlineStateAsync(forceRefresh: true, stoppingToken).ConfigureAwait(false);
-            _transfers.NotifyAvailability();
-            await _sync.TryAutoRunAsync(stoppingToken).ConfigureAwait(false);
-            await _profiles.TryAutoRunAsync(stoppingToken).ConfigureAwait(false);
-            await _hub.RefreshAsync(stoppingToken).ConfigureAwait(false);
-        }
-    }
-}

src/Explorer.App/Explorer.App.csproj

@@ -29,6 +29,10 @@
     <ProjectReference Include="..\Explorer.Application\Explorer.Application.csproj" />
     <ProjectReference Include="..\Explorer.Domain\Explorer.Domain.csproj" />
     <ProjectReference Include="..\Explorer.FileOperations\Explorer.FileOperations.csproj" />
+    <ProjectReference Include="..\Explorer.Host\Explorer.Host.csproj">
+      <ReferenceOutputAssembly>false</ReferenceOutputAssembly>
+    </ProjectReference>
+    <ProjectReference Include="..\Explorer.Hosting\Explorer.Hosting.csproj" />
     <ProjectReference Include="..\Explorer.Indexing\Explorer.Indexing.csproj" />
     <ProjectReference Include="..\Explorer.Plugin.Abstractions\Explorer.Plugin.Abstractions.csproj" />
     <ProjectReference Include="..\Explorer.Plugin.GoogleDrive\Explorer.Plugin.GoogleDrive.csproj" />
@@ -39,4 +43,17 @@
     <ProjectReference Include="..\Explorer.Storage.Sqlite\Explorer.Storage.Sqlite.csproj" />
     <ProjectReference Include="..\Explorer.Windows\Explorer.Windows.csproj" />
   </ItemGroup>
+  <Target Name="CopyExplorerHost" AfterTargets="Build">
+    <PropertyGroup>
+      <_HostDir>$([System.IO.Path]::GetFullPath('$(MSBuildThisFileDirectory)..\Explorer.Host\bin\$(Configuration)\net10.0-windows\'))</_HostDir>
+    </PropertyGroup>
+    <ItemGroup>
+      <_HostFiles Include="$(_HostDir)Explorer.Host.exe" />
+      <_HostFiles Include="$(_HostDir)Explorer.Host.dll" />
+      <_HostFiles Include="$(_HostDir)Explorer.Host.deps.json" />
+      <_HostFiles Include="$(_HostDir)Explorer.Host.runtimeconfig.json" />
+      <_HostFiles Include="$(_HostDir)Explorer.Host.pdb" />
+    </ItemGroup>
+    <Copy SourceFiles="@(_HostFiles)" DestinationFolder="$(OutputPath)" SkipUnchangedFiles="true" Condition="Exists('$(_HostDir)Explorer.Host.exe')" />
+  </Target>
 </Project>

src/Explorer.App/SettingsWindow.xaml

@@ -61,6 +61,16 @@
                   Content="Include archive contents in the index"/>
         <TextBlock TextWrapping="Wrap" Foreground="{DynamicResource FgMuted}" Margin="24,0,0,18" FontSize="12"
                    Text="When enabled, a scan lists files inside ZIP, RAR, 7z, TAR, and similar archives from the archive catalog — files are not extracted. Individual uncompressed sizes are stored. Folder totals still use the archive’s size on disk. Online-only cloud archives are skipped."/>
+        <CheckBox x:Name="AutoIndexRemovable" Margin="0,0,0,6"
+                  Content="Automatically index removable drives when they appear"/>
+        <TextBlock TextWrapping="Wrap" Foreground="{DynamicResource FgMuted}" Margin="24,0,0,18" FontSize="12"
+                   Text="USB and other removable volumes are queued for a full scan when they come online and are not indexed yet. Cloud locations are never auto-indexed. Online-only files are not hydrated."/>
+
+        <TextBlock Text="Background host" FontSize="16" FontWeight="SemiBold" Margin="0,8,0,10"/>
+        <CheckBox x:Name="BackgroundHostAtLogon" Margin="0,0,0,6"
+                  Content="Start Explorer.Host.exe at Windows sign-in"/>
+        <TextBlock TextWrapping="Wrap" Foreground="{DynamicResource FgMuted}" Margin="24,0,0,18" FontSize="12"
+                   Text="Registers a per-user logon task. The window still owns indexing in this version. If the host starts while this window is open, it exits because the index is already in use."/>
 
         <TextBlock Text="7-Zip" FontSize="16" FontWeight="SemiBold" Margin="0,8,0,10"/>
         <TextBlock TextWrapping="Wrap" Foreground="{DynamicResource FgMuted}" Margin="0,0,0,8" FontSize="12"

src/Explorer.App/SettingsWindow.xaml.cs

@@ -1,5 +1,6 @@
 using System.Windows;
 using Explorer.Application;
+using Explorer.Hosting;
 using Explorer.Presentation.ViewModels;
 
 namespace Explorer.App;
@@ -20,6 +21,8 @@ public partial class SettingsWindow : Window
         GroupNetwork.IsChecked = prefs.GroupNetworkPlaces;
         GroupCloud.IsChecked = prefs.GroupCloudPlaces;
         IndexArchives.IsChecked = prefs.IndexArchiveContents;
+        AutoIndexRemovable.IsChecked = prefs.AutoIndexRemovable;
+        BackgroundHostAtLogon.IsChecked = prefs.BackgroundHostAtLogon;
         ShowHidden.IsChecked = prefs.ShowHiddenFiles;
         ShowProtected.IsChecked = prefs.ShowProtectedSystemLocations;
         AutoClearQueue.IsChecked = prefs.AutoClearQueueWhenDone;
@@ -45,6 +48,8 @@ public partial class SettingsWindow : Window
             GroupNetworkPlaces = GroupNetwork.IsChecked == true,
             GroupCloudPlaces = GroupCloud.IsChecked == true,
             IndexArchiveContents = IndexArchives.IsChecked == true,
+            AutoIndexRemovable = AutoIndexRemovable.IsChecked == true,
+            BackgroundHostAtLogon = BackgroundHostAtLogon.IsChecked == true,
             ShowHiddenFiles = ShowHidden.IsChecked == true,
             ShowProtectedSystemLocations = ShowProtected.IsChecked == true,
             AutoClearQueueWhenDone = AutoClearQueue.IsChecked == true,
@@ -52,10 +57,41 @@ public partial class SettingsWindow : Window
             GitPath = string.IsNullOrWhiteSpace(GitPath.Text) ? null : GitPath.Text.Trim()
         };
         await _vm.ApplyPreferencesAsync(prefs).ConfigureAwait(true);
+        ApplyBackgroundHostAutostart(prefs.BackgroundHostAtLogon);
         DialogResult = true;
         Close();
     }
 
+    private void ApplyBackgroundHostAutostart(bool enabled)
+    {
+        if (enabled)
+        {
+            var exe = HostLogonAutostart.FindHostExecutable();
+            if (exe is null)
+            {
+                MessageBox.Show(
+                    this,
+                    "Explorer.Host.exe was not found next to Explorer Workbench, so the sign-in task was not registered.",
+                    "Background host",
+                    MessageBoxButton.OK,
+                    MessageBoxImage.Warning);
+                return;
+            }
+
+            if (!HostLogonAutostart.TryRegister(exe, out var error))
+            {
+                MessageBox.Show(this, error, "Background host", MessageBoxButton.OK, MessageBoxImage.Warning);
+            }
+
+            return;
+        }
+
+        if (!HostLogonAutostart.TryUnregister(out var unregisterError))
+        {
+            MessageBox.Show(this, unregisterError, "Background host", MessageBoxButton.OK, MessageBoxImage.Warning);
+        }
+    }
+
     private void OnBrowseSevenZip(object sender, RoutedEventArgs e)
     {
         var dlg = new Microsoft.Win32.OpenFileDialog