ProjectArcade

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using System.Runtime.InteropServices;
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using FILETIME = System.Runtime.InteropServices.ComTypes.FILETIME;
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namespace DokanNet.Native
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{
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    /// <summary>
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    /// Contains information that the <see cref="DokanOperationProxy.GetFileInformationProxy"/> function retrieves.
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    /// </summary>
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    /// <remarks>
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    /// The identifier that is stored in the nFileIndexHigh and nFileIndexLow members is called the file ID.
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    /// Support for file IDs is file system-specific. File IDs are not guaranteed to be unique over time,
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    /// because file systems are free to reuse them. In some cases, the file ID for a file can change over time.
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    /// 
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    /// In the FAT file system, the file ID is generated from the first cluster of the containing directory
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    /// and the byte offset within the directory of the entry for the file. Some defragmentation products
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    /// change this byte offset. (Windows in-box defragmentation does not.) Thus, a FAT file ID can change
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    /// over time.Renaming a file in the FAT file system can also change the file ID, but only if the new
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    /// file name is longer than the old one.
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    /// 
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    /// In the NTFS file system, a file keeps the same file ID until it is deleted. You can replace one file
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    /// with another file without changing the file ID by using the ReplaceFile function. However, the file ID
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    /// of the replacement file, not the replaced file, is retained as the file ID of the resulting file.
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    /// 
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    /// Not all file systems can record creation and last access time, and not all file systems record them
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    /// in the same manner. For example, on a Windows FAT file system, create time has a resolution of
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    /// 10 milliseconds, write time has a resolution of 2 seconds, and access time has a resolution of
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    /// 1 day (the access date). On the NTFS file system, access time has a resolution of 1 hour.
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    /// </remarks>
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    /// \see <a href="https://msdn.microsoft.com/en-us/library/windows/desktop/aa363788%28v=vs.85%29.aspx?f=255&MSPPError=-2147217396">BY_HANDLE_FILE_INFORMATION structure (MSDN)</a>
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    [StructLayout(LayoutKind.Sequential, Pack = 4)]
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    internal struct BY_HANDLE_FILE_INFORMATION
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    {
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        /// <summary>
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        /// The file attributes. For possible values and their descriptions.
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        /// </summary>
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        public uint dwFileAttributes;
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        /// <summary>
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        /// A <see cref="FILETIME"/> structure that specifies when a file or directory is created. 
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        /// If the underlying file system does not support creation time, this member is zero (0).
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        /// </summary>
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        public FILETIME ftCreationTime;
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        /// <summary>
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        ///  A <see cref="FILETIME"/> structure.
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        /// For a file, the structure specifies the last time that a file is read from or written to.
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        /// For a directory, the structure specifies when the directory is created.
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        /// For both files and directories, the specified date is correct, but the time of day is always set to midnight.
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        /// If the underlying file system does not support the last access time, this member is zero (0).
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        /// </summary>
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        public FILETIME ftLastAccessTime;
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        /// <summary>
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        /// A <see cref="FILETIME"/> structure. 
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        /// For a file, the structure specifies the last time that a file is written to. 
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        /// For a directory, the structure specifies when the directory is created. 
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        /// If the underlying file system does not support the last write time, this member is zero (0).
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        /// </summary>
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        public FILETIME ftLastWriteTime;
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        /// <summary>
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        /// The serial number of the volume that contains a file.
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        /// </summary>
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        internal uint dwVolumeSerialNumber;
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        /// <summary>
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        /// The high-order part of the file size.
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        /// </summary>
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        public uint nFileSizeHigh;
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        /// <summary>
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        /// The low-order part of the file size.
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        /// </summary>
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        public uint nFileSizeLow;
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        /// <summary>
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        /// The number of links to this file. 
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        /// For the FAT file system this member is always 1. 
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        /// For the NTFS file system, it can be more than 1.
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        /// </summary>
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        internal uint dwNumberOfLinks;
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        /// <summary>
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        /// The high-order part of a unique identifier that is associated with a file. 
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        /// For more information, see <see cref="nFileIndexLow"/>.
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        /// </summary>
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        internal uint nFileIndexHigh;
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        /// <summary>
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        /// The low-order part of a unique identifier that is associated with a file.
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        /// 
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        /// The identifier (low and high parts) and the volume serial number uniquely 
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        /// identify a file on a single computer. To determine whether two open handles 
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        /// represent the same file, combine the identifier and the volume serial number 
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        /// for each file and compare them.
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        /// 
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        /// The ReFS file system, introduced with Windows Server 2012, includes 128-bit 
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        /// file identifiers. To retrieve the 128-bit file identifier use the 
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        /// GetFileInformationByHandleEx function with FileIdInfo to retrieve 
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        /// the FILE_ID_INFO structure. The 64-bit identifier in this structure is not 
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        /// guaranteed to be unique on ReFS.
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        /// </summary>
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        internal uint nFileIndexLow;
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    }
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}