Here is the code:
[DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool CopyFileEx(string lpExistingFileName, string lpNewFileName,
IntPtr lpProgressRoutine, IntPtr lpData, ref Int32 pbCancel,
CopyFileFlags dwCopyFlags);
public void CopyFileWithProgressReports()
{
var lpProgressRoutineIntPtr = Marshal.GetFunctionPointerForDelegate(new CopyProgressRoutine(LpProgressRoutine));
int pbCancel = 0;
CopyFileEx(hugeFile, hugeFile + ".new", lpProgressRoutineIntPtr, IntPtr.Zero, ref pbCancel,
CopyFileFlags.COPY_FILE_RESTARTABLE);
}
private static CopyProgressResult LpProgressRoutine(long totalFileSize, long totalBytesTransferred, long streamSize,
long streamBytesTransferred, uint dwStreamNumber, CopyProgressCallbackReason dwCallbackReason, IntPtr hSourceFile,
IntPtr hDestinationFile, IntPtr lpData)
{
Console.WriteLine("{0:#,#} / {1:#,#}", totalBytesTransferred, totalFileSize);
return CopyProgressResult.PROGRESS_CONTINUE;
}
This code will run perfectly if you execute it in a single threaded fashion.
But, if you run it on a background thread and continue to do additional operations (just running it on a background thread work) that has nothing to do with the file system, it will crash, sometimes with a null reference exception, sometimes with attempt to write to protected memory, etc.
There is a very subtle bug here, can you figure out what it is?
Read more: Ayende @ Rahien
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