Setting timestamps on files / directories is extremely slow

I am working on a project that requires copying a lot of files and directories while keeping their original timestamps. Therefore I need to make many calls to the target methods SetCreationTime()

, SetLastWriteTime()

and SetLastAccessTime()

to copy the original values ​​from the source to the target. As shown in the screenshot below, these simple operations take up to 42% of the total computation time.

Since this limits my application performance enormously, I would like to speed up the process. I am assuming that each of these calls requires opening and closing a new stream in the file / directory. If this is the reason, I would like to keep this stream open until I have finished writing all the attributes. How to do it? I guess this will require using some P / Invoke.

Update:

I used Lucas's advice to use the WinAPI method CreateFile(..)

with FILE_WRITE_ATTRIBUTES

. To P / Call the method mentioned, I created the following wrapper:

public class Win32ApiWrapper
{
    [DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
    private static extern SafeFileHandle CreateFile(string lpFileName,
                                                    [MarshalAs(UnmanagedType.U4)] FileAccess dwDesiredAccess,
                                                    [MarshalAs(UnmanagedType.U4)] FileShare dwShareMode,
                                                    IntPtr lpSecurityAttributes, 
                                                    [MarshalAs(UnmanagedType.U4)] FileMode dwCreationDisposition,
                                                    [MarshalAs(UnmanagedType.U4)] FileAttributes dwFlagsAndAttributes,
                                                    IntPtr hTemplateFile);

    public static SafeFileHandle CreateFileGetHandle(string path, int fileAttributes)
    {
        return CreateFile(path,
                (FileAccess)(EFileAccess.FILE_WRITE_ATTRIBUTES | EFileAccess.FILE_WRITE_DATA),
                0,
                IntPtr.Zero,
                FileMode.Create,
                (FileAttributes)fileAttributes,
                IntPtr.Zero);
        }
}

      

        
        
        
      

    

The enumerations listed here can be found here . This allowed me to do everything just by opening the file once: create the file, apply all attributes, set timestamps, and copy the actual content from the original file.

FileInfo targetFile;
int fileAttributes;
IDictionary<string, long> timeStamps; 

using (var hFile = Win32ApiWrapper.CreateFileGetHandle(targetFile.FullName, attributeFlags))
using (var targetStream = new FileStream(hFile, FileAccess.Write))
{
    // copy file
    Win32ApiWrapper.SetFileTime(hFile, timeStamps);
}

      

        
        
        
      

    

Was it worth the effort? YES. This reduced the computation time by ~ 40% from 86 to 51.

Results before optimization:

Results after optimization: