Code Quality: Replace raw ABI pointers with ComObject instances for safer disposal by 0x5bfa · Pull Request #18684 · files-community/Files

0x5bfa · 2026-07-06T02:20:18Z

Resolved / Related Issues

We've been using raw ABI pointes, having us dispose COM instances via IUnknown::Release manually. This makes us a lot harder to manage the lifetime of each instance because normally managed instances are disposed automatically by GC and C# developers are not expected to take life cycle of any instance into account. This was because CsWin32 has only supported raw ABI pointers or ComImport, which is AOT unsafe, however, now CsWin32 supports generation of GeneratedComInterface COM interfaces. COM instances wrapped by ComObject are a managed object, we can use them safely without any trouble.

Feature: Improving Performance, optimizations, reliability and codebase #4180

Steps used to test these changes

Open Files

CC @yair100 @hez2010

0x5bfa · 2026-07-06T02:24:18Z

FYI @dongle-the-gadget too

Copilot

Pull request overview

This PR modernizes COM interop across the WinUI app and related projects by moving away from raw ABI pointers / manual Release() patterns toward CsWin32’s newer source-generated COM interfaces, with the intent of improving safety and maintainability (and aligning with the ongoing reliability/performance work tracked in #4180).

Changes:

Enable CsWin32 COM source generators + marshaling and update manual GUID helpers to value-based Guid constants.
Replace many ComPtr<T>/raw-pointer call sites with generated COM interfaces, out parameters, and a new ComHelpers utility for activation/casting/bind-to-handler.
Refactor file-operation progress sink implementation from a manually-built vtable to a [GeneratedComClass] implementation.

Reviewed changes

Copilot reviewed 48 out of 48 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
src/Files.App/ViewModels/UserControls/Widgets/QuickAccessWidgetViewModel.cs	Switch agile reference acquisition/resolution from raw pointers to generated COM interfaces.
src/Files.App/ViewModels/UserControls/Previews/ShellPreviewViewModel.cs	Replace D3D/DComp COM pointer plumbing with generated COM interface usage.
src/Files.App/Utils/Taskbar/SystemTrayIconWindow.cs	Update WNDPROC delegate alias to managed delegate type in CsWin32 extras.
src/Files.App/Utils/Storage/Helpers/SyncRootHelpers.cs	Replace status/quota COM calls with generated COM interfaces + `ComHelpers`.
src/Files.App/Utils/Storage/Helpers/MtpHelpers.cs	Replace raw shell COM pointers/enumeration with generated interfaces.
src/Files.App/Utils/Shell/PreviewHandler.cs	Update preview handler activation and initialization interfaces to generated COM types.
src/Files.App/Utils/Shell/OpenWithMenu.cs	Replace `IContextMenu*` lifetime management with generated COM interface usage.
src/Files.App/Utils/Shell/LaunchHelper.cs	Update activation manager creation to `ComHelpers.CoCreateInstance`.
src/Files.App/Utils/Shell/ItemStreamHelper.cs	Change helpers to return `IShellItem`/`IStream` interfaces instead of `IntPtr` + manual release.
src/Files.App/Utils/Shell/DetectionAndSharingHelper.cs	Replace COM pointer usage with generated COM interface calls.
src/Files.App/Services/Windows/WindowsWallpaperService.cs	Switch wallpaper COM activation to `ComHelpers` and generated interfaces.
src/Files.App/Services/Windows/WindowsRecentItemsService.cs	Replace shell folder enumeration + context menu invocation with generated COM interfaces.
src/Files.App/Services/Windows/WindowsDialogService.cs	Update file dialogs to use generated COM interfaces and `ComHelpers`.
src/Files.App/Services/Storage/StorageTrashBinService.cs	Replace Recycle Bin/file operation COM pointer usage with generated interfaces.
src/Files.App/Data/Items/WindowEx.cs	Update callback delegate aliases to managed delegate types in CsWin32 extras.
src/Files.App/Data/Items/WidgetRecentItem.cs	Change `ShellItem` storage from `ComPtr<IShellItem>` to `IShellItem`.
src/Files.App.Storage/Windows/WindowsStorable.cs	Change `ThisPtr` and `ContextMenu` from raw pointers to generated COM interfaces.
src/Files.App.Storage/Windows/WindowsFolder.cs	Update folder wrapper to use generated COM interfaces and managed enumeration.
src/Files.App.Storage/Windows/WindowsFile.cs	Update file wrapper to use generated COM interfaces.
src/Files.App.Storage/Windows/WindowsBulkOperationsSink.VTable.cs	Remove manually-implemented vtable-based progress sink.
src/Files.App.Storage/Windows/WindowsBulkOperationsSink.Methods.cs	Replace sink with `[GeneratedComClass]` implementation using `WeakReference`.
src/Files.App.Storage/Windows/WindowsBulkOperations.cs	Replace raw `IFileOperation*`/sink pointers with generated interfaces and managed sink.
src/Files.App.Storage/Windows/Managers/WindowsObjectPicker.cs	Update COM activation, `IDataObject` access, and VARIANT handling to managed marshalling types.
src/Files.App.Storage/Windows/Managers/WindowsFolderChangeWatcher.cs	Update WNDPROC delegate alias to managed delegate type in CsWin32 extras.
src/Files.App.Storage/Windows/Managers/WindowsDriveManager.cs	Adjust FOLDERID usage to value `Guid` instead of pointer deref.
src/Files.App.Storage/Windows/Managers/TaskbarManager.cs	Replace `ComPtr<ITaskbarList3>` with generated interface reference.
src/Files.App.Storage/Windows/Managers/SystemTrayManager.cs	Update WNDPROC delegate alias to managed delegate type in CsWin32 extras.
src/Files.App.Storage/Windows/IWindowsStorable.cs	Update interface to use generated COM interfaces instead of raw pointers.
src/Files.App.Storage/Windows/IWindowsFolder.cs	Update interface to use generated COM interfaces instead of raw pointers.
src/Files.App.Storage/Windows/Helpers/WindowsStorableHelpers.Shell.cs	Update shell helper extensions to use generated COM interfaces and `ComHelpers`.
src/Files.App.Storage/Windows/Helpers/WindowsStorableHelpers.Icon.cs	Update thumbnail/icon helper COM interactions to generated interfaces.
src/Files.App.Server/Program.cs	Update activation factory callback signature to unmanaged interface type.
src/Files.App.Server/Helpers.cs	Update `GetActivationFactory` signature/casts to unmanaged interface type.
src/Files.App.CsWin32/NativeMethods.json	Enable marshaling and COM source generators for CsWin32.
src/Files.App.CsWin32/ManualGuid.cs	Replace pointer-based GUID accessors with value `Guid` properties.
src/Files.App.CsWin32/IStorageProviderStatusUISourceFactory.cs	Convert to `[GeneratedComInterface]` with managed signatures.
src/Files.App.CsWin32/IStorageProviderStatusUISource.cs	Convert to `[GeneratedComInterface]` with managed signatures.
src/Files.App.CsWin32/IStorageProviderStatusUI.cs	Convert to `[GeneratedComInterface]` with managed signatures.
src/Files.App.CsWin32/IStorageProviderQuotaUI.cs	Convert to `[GeneratedComInterface]` with managed signatures.
src/Files.App.CsWin32/IOpenControlPanel.cs	Convert to `[GeneratedComInterface]` with managed signatures.
src/Files.App.CsWin32/IDetectionAndSharing.cs	Convert to `[GeneratedComInterface]` with managed signatures.
src/Files.App.CsWin32/Files.App.CsWin32.csproj	Run CsWin32 as a build task to keep outputs aligned with generator config.
src/Files.App.CsWin32/Extras.cs	Add managed callback delegates and update `IDCompositionTarget.SetRoot` signature.
src/Files.App.CsWin32/ComPtr`1.cs	Remove custom `ComPtr<T>` implementation.
src/Files.App.CsWin32/ComHelpers.cs	Add helper methods for COM activation/casting/bind-to-handler with generated interfaces.

Comments suppressed due to low confidence (1)

src/Files.App/Utils/Shell/LaunchHelper.cs:28

LaunchSettings ignores the HRESULT from CoCreateInstance and then uses the null-forgiving operator to call ActivateApplication. If COM activation fails, this will throw NullReferenceException. Handle activation failure explicitly and return early.

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

0x5bfa · 2026-07-07T05:22:46Z

Ready for review.

dongle-the-gadget · 2026-07-07T05:48:50Z

+	[GeneratedComInterface, Guid("BA6295C3-312E-544F-9FD5-1F81B21F3649"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+	public partial interface IStorageProviderQuotaUI


GeneratedComInterface won't work on the IStorageProvider APIs as they are IInspectable, not IUnknown.

Fixed in the latest commit, please take another look.

dongle-the-gadget · 2026-07-07T05:49:00Z

+	[GeneratedComInterface, Guid("D6B6A758-198D-5B80-977F-5FF73DA33118"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+	public partial interface IStorageProviderStatusUI


Same as above

dongle-the-gadget · 2026-07-07T05:49:11Z

+	[GeneratedComInterface, Guid("A306C249-3D66-5E70-9007-E43DF96051FF"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+	public partial interface IStorageProviderStatusUISource


Same as above

dongle-the-gadget · 2026-07-07T05:49:18Z

+	[GeneratedComInterface, Guid("12E46B74-4E5A-58D1-A62F-0376E8EE7DD8"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+	public partial interface IStorageProviderStatusUISourceFactory


Same as above

dongle-the-gadget · 2026-07-07T05:56:16Z

+		public static Guid IID_IStorageProviderStatusUISourceFactory { get; } = new("12E46B74-4E5A-58D1-A62F-0376E8EE7DD8");
+
+		public static Guid IID_IContextMenu { get; } = new("000214E4-0000-0000-C000-000000000046");
+		public static Guid IID_IEnumShellItems { get; } = new("70629033-E363-4A28-A567-0DB78006E6D7");
+		public static Guid IID_IShellItem { get; } = new("43826D1E-E718-42EE-BC55-A1E261C37BFE");
+		public static Guid IID_IShellItem2 { get; } = new("7E9FB0D3-919F-4307-AB2E-9B1860310C93");
+		public static Guid IID_IFileOperation { get; } = new("947AAB5F-0A5C-4C13-B4D6-4BF7836FC9F8");
+		public static Guid IID_IFileOpenDialog { get; } = new("D57C7288-D4AD-4768-BE02-9D969532D960");
+		public static Guid IID_IFileSaveDialog { get; } = new("84BCCD23-5FDE-4CDB-AEA4-AF64B83D78AB");
+		public static Guid IID_IDesktopWallpaper { get; } = new("B92B56A9-8B55-4E14-9A89-0199BBB6F93B");
+		public static Guid IID_IApplicationActivationManager { get; } = new("2E941141-7F97-4756-BA1D-9DECDE894A3D");
+		public static Guid IID_IQueryInfo { get; } = new("00021500-0000-0000-C000-000000000046");
+		public static Guid IID_IShellItemImageFactory { get; } = new("BCC18B79-BA16-442F-80C4-8A59C30C463B");
+		public static Guid IID_IShellLinkW { get; } = new("000214F9-0000-0000-C000-000000000046");
+		public static Guid IID_IShellItemArray { get; } = new("B63EA76D-1F85-456F-A19C-48159EFA858B");
+		public static Guid IID_IExecuteCommand { get; } = new("7F9185B0-CB92-43C5-80A9-92277A4F7B54");
+		public static Guid IID_IObjectWithSelection { get; } = new("1C9CD5BB-98E9-4491-A60F-31AACC72B83C");
+		public static Guid IID_IShellExtInit { get; } = new("000214E8-0000-0000-C000-000000000046");
+		public static Guid IID_IContextMenu2 { get; } = new("000214F4-0000-0000-C000-000000000046");
+		public static Guid IID_IDataObject { get; } = new("0000010E-0000-0000-C000-000000000046");


Nitpicking: using the string overload of Guid constructor here is rather inefficient. Using the int/byte overload would be better.

Fixed this too.

dongle-the-gadget · 2026-07-07T05:56:30Z

+		public static Guid CLSID_FileOperation { get; } = new("3AD05575-8857-4850-9277-11B85BDB8E09");
+		public static Guid CLSID_FileOpenDialog { get; } = new("DC1C5A9C-E88A-4DDE-A5A1-60F82A20AEF7");
+		public static Guid CLSID_FileSaveDialog { get; } = new("C0B4E2F3-BA21-4773-8DBA-335EC946EB8B");
+		public static Guid CLSID_DesktopWallpaper { get; } = new("C2CF3110-460E-4FC1-B9D0-8A1C0C9CC4BD");
+		public static Guid CLSID_ApplicationActivationManager { get; } = new("45BA127D-10A8-46EA-8AB7-56EA9078943C");
+		public static Guid CLSID_PinToFrequentExecute { get; } = new("B455F46E-E4AF-4035-B0A4-CF18D2F6F28E");
+		public static Guid CLSID_UnPinFromFrequentExecute { get; } = new("EE20EEBA-DF64-4A4E-B7BB-2D1C6B2DFCC1");
+		public static Guid CLSID_NewMenu { get; } = new("D969A300-E7FF-11d0-A93B-00A0C90F2719");
+		public static Guid CLSID_OpenWithMenu { get; } = new("09799AFB-AD67-11D1-ABCD-00C04FC30936");
+		public static Guid CLSID_DetectionAndSharing { get; } = new("1FDA955B-61FF-11DA-978C-0008744FAAB7");
+		public static Guid CLSID_OpenControlPanel { get; } = new("06622D85-6856-4460-8DE1-A81921B41C4B");


Same as above

dongle-the-gadget · 2026-07-07T05:56:38Z

+		public static Guid BHID_SFUIObject { get; } = new("3981E225-F559-11D3-8E3A-00C04F6837D5");
+		public static Guid BHID_EnumItems { get; } = new("94F60519-2850-4924-AA5A-D15E84868039");
+		public static Guid BHID_DataObject { get; } = new("B8C0BD9F-ED24-455C-83E6-D5390C4FE8C4");


Same as above

dongle-the-gadget · 2026-07-07T05:56:44Z

+		public static Guid FOLDERID_RecycleBinFolder { get; } = new("B7534046-3ECB-4C18-BE4E-64CD4CB7D6AC");
+		public static Guid FOLDERID_ComputerFolder { get; } = new("0AC0837C-BBF8-452A-850D-79D08E667CA7");


Same as above

Copilot AI review requested due to automatic review settings July 6, 2026 02:20

Copilot started reviewing on behalf of 0x5bfa July 6, 2026 02:20 View session

Copilot AI reviewed Jul 6, 2026

View reviewed changes

0x5bfa marked this pull request as draft July 6, 2026 02:28

0x5bfa force-pushed the cswin32sg branch from 22e682e to 8df1082 Compare July 7, 2026 05:02

0x5bfa marked this pull request as ready for review July 7, 2026 05:22

dongle-the-gadget suggested changes Jul 7, 2026

View reviewed changes

dongle-the-gadget reviewed Jul 7, 2026

View reviewed changes

Init

b592f79

0x5bfa force-pushed the cswin32sg branch from 6f6bea7 to b592f79 Compare July 7, 2026 07:55

		[GeneratedComInterface, Guid("BA6295C3-312E-544F-9FD5-1F81B21F3649"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
		public partial interface IStorageProviderQuotaUI

		[GeneratedComInterface, Guid("D6B6A758-198D-5B80-977F-5FF73DA33118"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
		public partial interface IStorageProviderStatusUI

		[GeneratedComInterface, Guid("A306C249-3D66-5E70-9007-E43DF96051FF"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
		public partial interface IStorageProviderStatusUISource

		[GeneratedComInterface, Guid("12E46B74-4E5A-58D1-A62F-0376E8EE7DD8"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
		public partial interface IStorageProviderStatusUISourceFactory

		public static Guid FOLDERID_RecycleBinFolder { get; } = new("B7534046-3ECB-4C18-BE4E-64CD4CB7D6AC");
		public static Guid FOLDERID_ComputerFolder { get; } = new("0AC0837C-BBF8-452A-850D-79D08E667CA7");

Uh oh!

Uh oh!

Conversation

0x5bfa commented Jul 6, 2026

Resolved / Related Issues

Steps used to test these changes

Uh oh!

0x5bfa commented Jul 6, 2026

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

0x5bfa commented Jul 7, 2026

Uh oh!

Uh oh!

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants