Small fixes in FileSystemEnumerator for Windows.#126544
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teo-tsirpanis wants to merge 4 commits intodotnet:mainfrom
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Small fixes in FileSystemEnumerator for Windows.#126544teo-tsirpanis wants to merge 4 commits intodotnet:mainfrom
FileSystemEnumerator for Windows.#126544teo-tsirpanis wants to merge 4 commits intodotnet:mainfrom
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…temEnumerator buffer Agent-Logs-Url: https://github.com/teo-tsirpanis/dotnet-runtime/sessions/233c35f2-6fa4-4409-b093-93f4a80a0598 Co-authored-by: teo-tsirpanis <12659251+teo-tsirpanis@users.noreply.github.com>
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Pull request overview
This PR fixes Windows-specific implementation details in FileSystemEnumerator<TResult> to ensure the intended OS behaviors are actually applied and to make the NT query buffer’s alignment requirement explicit.
Changes:
- Replace
using (default(DisableMediaInsertionPrompt))withusing (DisableMediaInsertionPrompt.Create())so the media insertion prompt suppression is actually enabled. - Allocate the directory query buffer via
NativeMemory.AlignedAlloc(..., sizeof(ulong))and free it viaNativeMemory.AlignedFree, switching_bufferfromIntPtrtovoid*. - Update the
NtQueryDirectoryFileinterop signature to acceptvoid*forFileInformation, matching the updated buffer type.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
src/libraries/System.Private.CoreLib/src/System/IO/Enumeration/FileSystemEnumerator.Windows.cs |
Uses the correct prompt-suppression factory and switches the query buffer to explicitly aligned native allocation. |
src/libraries/Common/src/Interop/Windows/NtDll/Interop.NtQueryDirectoryFile.cs |
Updates the P/Invoke signature to take a raw pointer for the output buffer. |
teo-tsirpanis
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Apr 5, 2026
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| // NtQueryDirectoryFile needs its buffer to be 64bit aligned to work | ||
| // successfully with FileFullDirectoryInformation on ARM32. AllocHGlobal | ||
| // will return pointers aligned as such, new byte[] does not. | ||
| _buffer = Marshal.AllocHGlobal(_bufferLength); | ||
| // successfully with FileFullDirectoryInformation on ARM32. AlignedAlloc | ||
| // guarantees the required alignment, new byte[] does not. | ||
| _buffer = NativeMemory.AlignedAlloc((nuint)_bufferLength, sizeof(ulong)); |
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Could we switch to just Alloc now that win-arm is not supported?
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This PR was created with the assistance of GitHub Copilot.
default(DisableMediaInsertionPrompt), withDisableMediaInsertionPrompt.Create()._bufferwas updated to be backed byNativeMemory.AlignedAllocinstead ofMarshal.AllocHGlobal. This makes the alignment requirement explicit and might increase performance.