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dotnet: implement new Delete design and POSIX semantics

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This commit is contained in:
Bill Zissimopoulos
2021-10-20 12:23:14 +01:00
parent 81248f3899
commit 76bfa395a8
6 changed files with 187 additions and 54 deletions
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93
src/dotnet/FileSystemBase.cs
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@ -289,6 +289,9 @@ namespace Fsp
/// </summary>
/// <remarks>
/// <para>
/// (NOTE: use of this function with the CleanupDelete flag is not recommended;
/// use Delete instead.)
/// </para><para>
/// When CreateFile is used to open or create a file the kernel creates a kernel mode file
/// object (type FILE_OBJECT) and a handle for it, which it returns to user-mode. The handle may
/// be duplicated (using DuplicateHandle), but all duplicate handles always refer to the same
@ -342,6 +345,7 @@ namespace Fsp
/// </param>
/// <seealso cref="CanDelete"/>
/// <seealso cref="SetDelete"/>
/// <seealso cref="Delete"/>
/// <seealso cref="Close"/>
public virtual void Cleanup(
Object FileNode,
@ -598,12 +602,14 @@ namespace Fsp
/// </summary>
/// <remarks>
/// <para>
/// (NOTE: use of this function is not recommended; use Delete instead.)
/// </para><para>
/// This function tests whether a file or directory can be safely deleted. This function does
/// not need to perform access checks, but may performs tasks such as check for empty
/// directories, etc.
/// </para><para>
/// This function should <b>NEVER</b> delete the file or directory in question. Deletion should
/// happen during Cleanup with the FspCleanupDelete flag set.
/// happen during Cleanup with the CleanupDelete flag set.
/// </para><para>
/// This function gets called when Win32 API's such as DeleteFile or RemoveDirectory are used.
/// It does not get called when a file or directory is opened with FILE_DELETE_ON_CLOSE.
@ -624,6 +630,7 @@ namespace Fsp
/// <returns>STATUS_SUCCESS or error code.</returns>
/// <seealso cref="Cleanup"/>
/// <seealso cref="SetDelete"/>
/// <seealso cref="Delete"/>
public virtual Int32 CanDelete(
Object FileNode,
Object FileDesc,
@ -1036,12 +1043,14 @@ namespace Fsp
/// </summary>
/// <remarks>
/// <para>
/// (NOTE: use of this function is not recommended; use Delete instead.)
/// </para><para>
/// This function sets a flag to indicates whether the FSD file should delete a file
/// when it is closed. This function does not need to perform access checks, but may
/// performs tasks such as check for empty directories, etc.
/// </para><para>
/// This function should <b>NEVER</b> delete the file or directory in question. Deletion should
/// happen during Cleanup with the FspCleanupDelete flag set.
/// happen during Cleanup with the CleanupDelete flag set.
/// </para><para>
/// This function gets called when Win32 API's such as DeleteFile or RemoveDirectory are used.
/// It does not get called when a file or directory is opened with FILE_DELETE_ON_CLOSE.
@ -1067,6 +1076,7 @@ namespace Fsp
/// <returns>STATUS_SUCCESS or error code.</returns>
/// <seealso cref="Cleanup"/>
/// <seealso cref="CanDelete"/>
/// <seealso cref="Delete"/>
public virtual Int32 SetDelete(
Object FileNode,
Object FileDesc,
@ -1188,6 +1198,85 @@ namespace Fsp
{
return STATUS_INVALID_DEVICE_REQUEST;
}
/// <summary>
/// Sets the file delete flag or deletes a file or directory.
/// </summary>
/// <remarks>
/// <para>
/// This function replaces CanDelete, SetDelete and uses of Cleanup with the CleanupDelete flag
/// and is recommended for use in all new code.
/// </para><para>
/// Due to the complexity of file deletion in the Windows file system this function is used
/// in many scenarios. Its usage is controlled by the Flags parameter:
/// <list>
/// <item>FILE_DISPOSITION_DO_NOT_DELETE: Unmark the file for deletion.
/// Do <b>NOT</b> delete the file either now or at Cleanup time.</item>
/// <item>FILE_DISPOSITION_DELETE: Mark the file for deletion,
/// but do <b>NOT</b> delete the file. The file will be deleted at Cleanup time
/// (via a call to Delete with Flags = -1).
/// This function does not need to perform access checks, but may
/// performs tasks such as check for empty directories, etc.</item>
/// <item>FILE_DISPOSITION_DELETE | FILE_DISPOSITION_POSIX_SEMANTICS: Delete the file
/// <b>NOW</b> using POSIX semantics. Open user mode handles to the file remain valid.
/// This case will be received only when SupportsPosixUnlinkRename is set.</item>
/// <item>-1: Delete the file <b>NOW</b> using regular Windows semantics.
/// Called during Cleanup with no open user mode handles remaining.
/// If a file system implements Delete, Cleanup should <b>NOT</b> be used for deletion anymore.</item>
/// </list>
/// </para><para>
/// This function gets called in all file deletion scenarios:
/// <list>
/// <item>When the DeleteFile or RemoveDirectory API's are used.</item>
/// <item>When the SetInformationByHandle API with FileDispositionInfo or FileDispositionInfoEx is used.</item>
/// <item>When a file is opened using FILE_DELETE_ON_CLOSE.</item>
/// <item>Etc.</item>
/// </list>
/// </para><para>
/// NOTE: Delete takes precedence over CanDelete, SetDelete and Cleanup with the CleanupDelete flag.
/// This means that if Delete is defined, CanDelete and SetDelete will never be called and
/// Cleanup will never be called with the CleanupDelete flag.
/// </para>
/// </remarks>
/// <param name="FileNode">
/// The file node of the file or directory.
/// </param>
/// <param name="FileDesc">
/// The file descriptor of the file or directory.
/// </param>
/// <param name="FileName">
/// The name of the file or directory.
/// </param>
/// <param name="Flags">
/// File disposition flags.
/// </param>
/// <returns>STATUS_SUCCESS or error code.</returns>
/// <seealso cref="Cleanup"/>
/// <seealso cref="CanDelete"/>
/// <seealso cref="SetDelete"/>
public virtual Int32 Delete(
Object FileNode,
Object FileDesc,
String FileName,
UInt32 Flags)
{
switch (Flags)
{
case FILE_DISPOSITION_DO_NOT_DELETE:
return SetDelete(FileNode, FileDesc, FileName, false);
case FILE_DISPOSITION_DELETE:
return SetDelete(FileNode, FileDesc, FileName, true);
case FILE_DISPOSITION_DELETE | FILE_DISPOSITION_POSIX_SEMANTICS:
return STATUS_INVALID_PARAMETER;
case ~(UInt32)0:
return STATUS_NOT_IMPLEMENTED;
default:
return STATUS_INVALID_PARAMETER;
}
}
/* helpers */
/// <summary>