#眉標=TxF、P/Invoke、NTFS
#副標=交易式的檔案處理(1)
#大標=TxF讓檔案系統也能達到交易控制
#作者=文／圖 吳剛志


==================<BOX>=============================
程式1

public static void CheckFiles(string[] files)
{
　Console.WriteLine();
　Console.WriteLine("確認檔案是否存在?");
　foreach (string file in files)
　{
　　Console.WriteLine(
　　" - 檔案({0}): {1}",
　　file,
　　File.Exists(file)? "存在":"不存在");
　}
　Console.WriteLine();
}
public static void Main(string[] args)
{
　// 建立 KTM transaction object
　IntPtr transaction = CreateTransaction(
　　IntPtr.Zero,
　　IntPtr.Zero,
　　0, 0, 0, 0,
　　null);
　string[] files = new string[] {
　　@"c:\file1.txt",
　　@"c:\file2.txt",
　　@"c:\file3.txt"};
　CheckFiles(files);
　　try
    {
     foreach (string file in files)
     {
　　　Console.Write("刪除檔案({0}): ", file);
　　　// 使用支援交易的 delete file API
　　　if (DeleteFileTransactedW(
       file, 
       transaction) == true)
       {
       Console.WriteLine("刪除成功");
       }
　　　else
　　　{
       Console.WriteLine("刪除失敗");
       throw new FileNotFoundException(
       "can not delete file", 
       file);
　　　}
     }

　// 認可交易
　　Console.WriteLine("認可交易");
　　CommitTransaction(transaction);
    }
　catch (Exception)
　{
　// 還原交易
　　Console.WriteLine("還原交易");
　　RollbackTransaction(transaction);
    }
    CloseHandle(transaction);
    CheckFiles(files);
}
====================<end>============================




==================<BOX>=============================
程式2
[DllImport("Kernel32.dll")]
private static extern bool DeleteFileTransactedW(
  [MarshalAs(UnmanagedType.LPWStr)]string file, 
  IntPtr transaction);

[DllImport("Kernel32.dll")]
private static extern bool CloseHandle(IntPtr handle);

[DllImport("Ktmw32.dll")]
private static extern bool CommitTransaction(
  IntPtr transaction);

[DllImport("Ktmw32.dll")]
private static extern bool RollbackTransaction(
  IntPtr transaction);

[DllImport("Ktmw32.dll")]
private static extern IntPtr CreateTransaction(
  IntPtr securityAttributes, 
  IntPtr guid, 
  int options, 
  int isolationLevel, 
  int isolationFlags, 
  int milliSeconds, 
  string description);
================================<end>=========================




==================<BOX>=============================
程式3
public static void Main(string[] args)
{
  // 建立 KTM transaction object
  IntPtr transaction = CreateTransaction(
    IntPtr.Zero,
    IntPtr.Zero,
    0, 0, 0, 0,
    null);

  string[] files = new string[] {
    @"c:\file1.txt",
    @"c:\file2.txt",
    @"c:\file3.txt"};
  CheckFiles(files);
   try
   {
    foreach (string file in files)
    {
     Console.Write("刪除檔案({0}): ", file);
     // 使用支援交易的 delete file API
      if (DeleteFileTransactedW(
       file, 
       transaction) == true)
       {
        Console.WriteLine("刪除成功");
       }
       else
       {
       Console.WriteLine("刪除失敗");
       throw new InvalidOperationException();
       }
      }

// 在交易中(未認可) 時檢查檔案是否存在
  CheckFiles(files);
  // 認可交易
  Console.WriteLine("按下 [ENTER] 之後，認可交易...");
  Console.ReadLine();
  CommitTransaction(transaction);
  }
  catch (Exception ex)
  {
    // 還原交易
    Console.WriteLine("還原交易:\nException: {0}", ex);
    RollbackTransaction(transaction);
  }
  CloseHandle(transaction);
  CheckFiles(files);
}
================================<end>=========================




==================<BOX>=============================
程式4
public static void CopyFilesTransacted(
　int maxcount, 
　IntPtr transaction)
{
　bool dummy = false;
　for (int count = 1; count <= maxcount; count++)
　{
   CopyFileTransacted(
　　@"C:\SamplePicture.jpg",
　　string.Format(
     @"E:\Temp\TXF\FILE-{0:D05}.jpg", 
　　　count),
     IntPtr.Zero,
     IntPtr.Zero,
     ref dummy,
     0,
     transaction);
   }
}

public static void CopyFiles(int maxcount)
{
　for (int count = 1; count <= maxcount; count++)
　{
   CopyFile(
　　@"C:\SamplePicture.jpg",
　　string.Format(
     @"E:\Temp\TXF\FILE-{0:D05}.jpg", 
　　count),
   false);
　}
}
================================<end>=========================