mcs/class/corlib/System.IO/File.cs

   1 //
   2 // System.IO.File.cs
   3 //
   4 //
   5 // Authors:
   6 //   Miguel de Icaza (miguel@ximian.com)
   7 //   Jim Richardson  (develop@wtfo-guru.com)
   8 //   Dan Lewis       (dihlewis@yahoo.co.uk)
   9 //   Ville Palo      (vi64pa@kolumbus.fi)
  10 //
  11 // Copyright 2002 Ximian, Inc. http://www.ximian.com
  12 // Copyright (C) 2001 Moonlight Enterprises, All Rights Reserved
  13 // Copyright (C) 2004, 2006, 2010 Novell, Inc (http://www.novell.com)
  14 //
  15 // Permission is hereby granted, free of charge, to any person obtaining
  16 // a copy of this software and associated documentation files (the
  17 // "Software"), to deal in the Software without restriction, including
  18 // without limitation the rights to use, copy, modify, merge, publish,
  19 // distribute, sublicense, and/or sell copies of the Software, and to
  20 // permit persons to whom the Software is furnished to do so, subject to
  21 // the following conditions:
  22 //
  23 // The above copyright notice and this permission notice shall be
  24 // included in all copies or substantial portions of the Software.
  25 //
  26 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  27 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  28 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  29 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  30 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  31 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  32 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  33 //
  34
  35 using System;
  36 using System.Collections.Generic;
  37 using System.Diagnostics;
  38 using System.Security;
  39 using System.Text;
  40 using System.Runtime.InteropServices;
  41
  42 #if !NET_2_1
  43 using System.Security.AccessControl;
  44 #endif
  45
  46 namespace System.IO
  47 {
  48         [ComVisible (true)]
  49         public static class File
  50         {
  51                 public static void AppendAllText (string path, string contents)
  52                 {
  53                         using (TextWriter w = new StreamWriter (path, true)) {
  54                                 w.Write (contents);
  55                         }
  56                 }
  57
  58                 public static void AppendAllText (string path, string contents, Encoding encoding)
  59                 {
  60                         using (TextWriter w = new StreamWriter (path, true, encoding)) {
  61                                 w.Write (contents);
  62                         }
  63                 }
  64
  65                 public static StreamWriter AppendText (string path)
  66                 {
  67                         return new StreamWriter (path, true);
  68                 }
  69
  70                 public static void Copy (string sourceFileName, string destFileName)
  71                 {
  72                         Copy (sourceFileName, destFileName, false);
  73                 }
  74
  75                 public static void Copy (string sourceFileName, string destFileName, bool overwrite)
  76                 {
  77                         MonoIOError error;
  78
  79                         if (sourceFileName == null)
  80                                 throw new ArgumentNullException ("sourceFileName");
  81                         if (destFileName == null)
  82                                 throw new ArgumentNullException ("destFileName");
  83                         if (sourceFileName.Length == 0)
  84                                 throw new ArgumentException ("An empty file name is not valid.", "sourceFileName");
  85                         if (sourceFileName.Trim ().Length == 0 || sourceFileName.IndexOfAny (Path.InvalidPathChars) != -1)
  86                                 throw new ArgumentException ("The file name is not valid.");
  87                         if (destFileName.Length == 0)
  88                                 throw new ArgumentException ("An empty file name is not valid.", "destFileName");
  89                         if (destFileName.Trim ().Length == 0 || destFileName.IndexOfAny (Path.InvalidPathChars) != -1)
  90                                 throw new ArgumentException ("The file name is not valid.");
  91
  92                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
  93
  94                         if (!MonoIO.Exists (sourceFileName, out error))
  95                                 throw new FileNotFoundException (Locale.GetText ("{0} does not exist", sourceFileName), sourceFileName);
  96                         if ((GetAttributes (sourceFileName) & FileAttributes.Directory) == FileAttributes.Directory)
  97                                 throw new ArgumentException (Locale.GetText ("{0} is a directory", sourceFileName));
  98
  99                         if (MonoIO.Exists (destFileName, out error)) {
 100                                 if ((GetAttributes (destFileName) & FileAttributes.Directory) == FileAttributes.Directory)
 101                                         throw new ArgumentException (Locale.GetText ("{0} is a directory", destFileName));
 102                                 if (!overwrite)
 103                                         throw new IOException (Locale.GetText ("{0} already exists", destFileName));
 104                         }
 105
 106                         string DirName = Path.GetDirectoryName (destFileName);
 107                         if (DirName != String.Empty && !Directory.Exists (DirName))
 108                                 throw new DirectoryNotFoundException (Locale.GetText ("Destination directory not found: {0}",DirName));
 109
 110                         if (!MonoIO.CopyFile (sourceFileName, destFileName, overwrite, out error)) {
 111                                 string p = Locale.GetText ("{0}\" or \"{1}", sourceFileName, destFileName);
 112                                 throw MonoIO.GetException (p, error);
 113                         }
 114                 }
 115
 116                 public static FileStream Create (string path)
 117                 {
 118                         return Create (path, 8192);
 119                 }
 120
 121                 public static FileStream Create (string path, int bufferSize)
 122                 {
 123                         return new FileStream (path, FileMode.Create, FileAccess.ReadWrite,
 124                                 FileShare.None, bufferSize);
 125                 }
 126
 127                 [MonoLimitation ("FileOptions are ignored")]
 128                 public static FileStream Create (string path, int bufferSize,
 129                                                  FileOptions options)
 130                 {
 131                         return new FileStream (path, FileMode.Create, FileAccess.ReadWrite,
 132                                 FileShare.None, bufferSize, options);
 133                 }
 134
 135 #if !NET_2_1
 136                 [MonoLimitation ("FileOptions and FileSecurity are ignored")]
 137                 public static FileStream Create (string path, int bufferSize,
 138                                                  FileOptions options,
 139                                                  FileSecurity fileSecurity)
 140                 {
 141                         return new FileStream (path, FileMode.Create, FileAccess.ReadWrite,
 142                                 FileShare.None, bufferSize, options);
 143                 }
 144 #endif
 145
 146                 public static StreamWriter CreateText (string path)
 147                 {
 148                         return new StreamWriter (path, false);
 149                 }
 150
 151                 public static void Delete (string path)
 152                 {
 153                         Path.Validate (path);
 154                         if (Directory.Exists (path))
 155                                 throw new UnauthorizedAccessException(Locale.GetText ("{0} is a directory", path));
 156
 157                         string DirName = Path.GetDirectoryName(path);
 158                         if (DirName != String.Empty && !Directory.Exists (DirName))
 159                                 throw new DirectoryNotFoundException (Locale.GetText ("Could not find a part of the path \"{0}\".", path));
 160
 161                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
 162
 163                         MonoIOError error;
 164
 165                         if (!MonoIO.DeleteFile (path, out error)){
 166                                 if (error != MonoIOError.ERROR_FILE_NOT_FOUND)
 167                                         throw MonoIO.GetException (path, error);
 168                         }
 169                 }
 170
 171                 public static bool Exists (string path)
 172                 {
 173                         // For security reasons no exceptions are
 174                         // thrown, only false is returned if there is
 175                         // any problem with the path or permissions.
 176                         // Minimizes what information can be
 177                         // discovered by using this method.
 178                         if (String.IsNullOrWhiteSpace (path) || path.IndexOfAny(Path.InvalidPathChars) >= 0)
 179                                 return false;
 180
 181                         // on Moonlight this does not throw but returns false
 182                         if (!SecurityManager.CheckElevatedPermissions ())
 183                                 return false;
 184
 185                         MonoIOError error;
 186                         return MonoIO.ExistsFile (path, out error);
 187                 }
 188
 189 #if !NET_2_1
 190                 public static FileSecurity GetAccessControl (string path)
 191                 {
 192                         // AccessControlSections.Audit requires special permissions.
 193                         return GetAccessControl (path,
 194                                                  AccessControlSections.Owner |
 195                                                  AccessControlSections.Group |
 196                                                  AccessControlSections.Access);
 197                 }
 198
 199                 public static FileSecurity GetAccessControl (string path, AccessControlSections includeSections)
 200                 {
 201                         return new FileSecurity (path, includeSections);
 202                 }
 203 #endif
 204
 205                 public static FileAttributes GetAttributes (string path)
 206                 {
 207                         Path.Validate (path);
 208                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
 209
 210                         MonoIOError error;
 211                         FileAttributes attrs;
 212
 213                         attrs = MonoIO.GetFileAttributes (path, out error);
 214                         if (error != MonoIOError.ERROR_SUCCESS)
 215                                 throw MonoIO.GetException (path, error);
 216                         return attrs;
 217                 }
 218
 219                 public static DateTime GetCreationTime (string path)
 220                 {
 221                         MonoIOStat stat;
 222                         MonoIOError error;
 223                         Path.Validate (path);
 224                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
 225
 226                         if (!MonoIO.GetFileStat (path, out stat, out error)) {
 227                                 if (error == MonoIOError.ERROR_PATH_NOT_FOUND || error == MonoIOError.ERROR_FILE_NOT_FOUND)
 228                                         return DefaultLocalFileTime;
 229                                 else
 230                                         throw new IOException (path);
 231                         }
 232                         return DateTime.FromFileTime (stat.CreationTime);
 233                 }
 234
 235                 public static DateTime GetCreationTimeUtc (string path)
 236                 {
 237                         return GetCreationTime (path).ToUniversalTime ();
 238                 }
 239
 240                 public static DateTime GetLastAccessTime (string path)
 241                 {
 242                         MonoIOStat stat;
 243                         MonoIOError error;
 244                         Path.Validate (path);
 245                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
 246
 247                         if (!MonoIO.GetFileStat (path, out stat, out error)) {
 248                                 if (error == MonoIOError.ERROR_PATH_NOT_FOUND || error == MonoIOError.ERROR_FILE_NOT_FOUND)
 249                                         return DefaultLocalFileTime;
 250                                 else
 251                                         throw new IOException (path);
 252                         }
 253                         return DateTime.FromFileTime (stat.LastAccessTime);
 254                 }
 255
 256                 public static DateTime GetLastAccessTimeUtc (string path)
 257                 {
 258                         return GetLastAccessTime (path).ToUniversalTime ();
 259                 }
 260
 261                 public static DateTime GetLastWriteTime (string path)
 262                 {
 263                         MonoIOStat stat;
 264                         MonoIOError error;
 265                         Path.Validate (path);
 266                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
 267
 268                         if (!MonoIO.GetFileStat (path, out stat, out error)) {
 269                                 if (error == MonoIOError.ERROR_PATH_NOT_FOUND || error == MonoIOError.ERROR_FILE_NOT_FOUND)
 270                                         return DefaultLocalFileTime;
 271                                 else
 272                                         throw new IOException (path);
 273                         }
 274                         return DateTime.FromFileTime (stat.LastWriteTime);
 275                 }
 276
 277                 public static DateTime GetLastWriteTimeUtc (string path)
 278                 {
 279                         return GetLastWriteTime (path).ToUniversalTime ();
 280                 }
 281
 282                 public static void Move (string sourceFileName, string destFileName)
 283                 {
 284                         if (sourceFileName == null)
 285                                 throw new ArgumentNullException ("sourceFileName");
 286                         if (destFileName == null)
 287                                 throw new ArgumentNullException ("destFileName");
 288                         if (sourceFileName.Length == 0)
 289                                 throw new ArgumentException ("An empty file name is not valid.", "sourceFileName");
 290                         if (sourceFileName.Trim ().Length == 0 || sourceFileName.IndexOfAny (Path.InvalidPathChars) != -1)
 291                                 throw new ArgumentException ("The file name is not valid.");
 292                         if (destFileName.Length == 0)
 293                                 throw new ArgumentException ("An empty file name is not valid.", "destFileName");
 294                         if (destFileName.Trim ().Length == 0 || destFileName.IndexOfAny (Path.InvalidPathChars) != -1)
 295                                 throw new ArgumentException ("The file name is not valid.");
 296
 297                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
 298
 299                         MonoIOError error;
 300                         if (!MonoIO.Exists (sourceFileName, out error))
 301                                 throw new FileNotFoundException (Locale.GetText ("{0} does not exist", sourceFileName), sourceFileName);
 302
 303                         // Don't check for this error here to allow the runtime
 304                         // to check if sourceFileName and destFileName are equal.
 305                         // Comparing sourceFileName and destFileName is not enough.
 306                         //if (MonoIO.Exists (destFileName, out error))
 307                         //      throw new IOException (Locale.GetText ("{0} already exists", destFileName));
 308
 309                         string DirName;
 310                         DirName = Path.GetDirectoryName (destFileName);
 311                         if (DirName != String.Empty && !Directory.Exists (DirName))
 312                                 throw new DirectoryNotFoundException (Locale.GetText ("Could not find a part of the path."));
 313
 314                         if (!MonoIO.MoveFile (sourceFileName, destFileName, out error)) {
 315                                 if (error == MonoIOError.ERROR_ALREADY_EXISTS)
 316                                         throw MonoIO.GetException (error);
 317                                 else if (error == MonoIOError.ERROR_SHARING_VIOLATION)
 318                                         throw MonoIO.GetException (sourceFileName, error);
 319
 320                                 throw MonoIO.GetException (error);
 321                         }
 322                 }
 323
 324                 public static FileStream Open (string path, FileMode mode)
 325                 {
 326                         return new FileStream (path, mode, mode == FileMode.Append ? FileAccess.Write : FileAccess.ReadWrite, FileShare.None);
 327                 }
 328
 329                 public static FileStream Open (string path, FileMode mode, FileAccess access)
 330                 {
 331                         return new FileStream (path, mode, access, FileShare.None);
 332                 }
 333
 334                 public static FileStream Open (string path, FileMode mode, FileAccess access,
 335                                                FileShare share)
 336                 {
 337                         return new FileStream (path, mode, access, share);
 338                 }
 339
 340                 public static FileStream OpenRead (string path)
 341                 {
 342                         return new FileStream (path, FileMode.Open, FileAccess.Read, FileShare.Read);
 343                 }
 344
 345                 public static StreamReader OpenText (string path)
 346                 {
 347                         return new StreamReader (path);
 348                 }
 349
 350                 public static FileStream OpenWrite (string path)
 351                 {
 352                         return new FileStream(path, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None);
 353                 }
 354
 355                 public static void Replace (string sourceFileName,
 356                                             string destinationFileName,
 357                                             string destinationBackupFileName)
 358                 {
 359                         Replace (sourceFileName, destinationFileName, destinationBackupFileName, false);
 360                 }
 361
 362                 public static void Replace (string sourceFileName,
 363                                             string destinationFileName,
 364                                             string destinationBackupFileName,
 365                                             bool ignoreMetadataErrors)
 366                 {
 367                         MonoIOError error;
 368
 369                         if (sourceFileName == null)
 370                                 throw new ArgumentNullException ("sourceFileName");
 371                         if (destinationFileName == null)
 372                                 throw new ArgumentNullException ("destinationFileName");
 373                         if (sourceFileName.Trim ().Length == 0 || sourceFileName.IndexOfAny (Path.InvalidPathChars) != -1)
 374                                 throw new ArgumentException ("sourceFileName");
 375                         if (destinationFileName.Trim ().Length == 0 || destinationFileName.IndexOfAny (Path.InvalidPathChars) != -1)
 376                                 throw new ArgumentException ("destinationFileName");
 377
 378                         string fullSource = Path.GetFullPath (sourceFileName);
 379                         string fullDest = Path.GetFullPath (destinationFileName);
 380                         if (MonoIO.ExistsDirectory (fullSource, out error))
 381                                 throw new IOException (Locale.GetText ("{0} is a directory", sourceFileName));
 382                         if (MonoIO.ExistsDirectory (fullDest, out error))
 383                                 throw new IOException (Locale.GetText ("{0} is a directory", destinationFileName));
 384
 385                         if (!Exists (fullSource))
 386                                 throw new FileNotFoundException (Locale.GetText ("{0} does not exist", sourceFileName),
 387                                                                  sourceFileName);
 388                         if (!Exists (fullDest))
 389                                 throw new FileNotFoundException (Locale.GetText ("{0} does not exist", destinationFileName),
 390                                                                  destinationFileName);
 391                         if (fullSource == fullDest)
 392                                 throw new IOException (Locale.GetText ("Source and destination arguments are the same file."));
 393
 394                         string fullBackup = null;
 395                         if (destinationBackupFileName != null) {
 396                                 if (destinationBackupFileName.Trim ().Length == 0 ||
 397                                     destinationBackupFileName.IndexOfAny (Path.InvalidPathChars) != -1)
 398                                         throw new ArgumentException ("destinationBackupFileName");
 399
 400                                 fullBackup = Path.GetFullPath (destinationBackupFileName);
 401                                 if (MonoIO.ExistsDirectory (fullBackup, out error))
 402                                         throw new IOException (Locale.GetText ("{0} is a directory", destinationBackupFileName));
 403                                 if (fullSource == fullBackup)
 404                                         throw new IOException (Locale.GetText ("Source and backup arguments are the same file."));
 405                                 if (fullDest == fullBackup)
 406                                         throw new IOException (Locale.GetText (
 407                                                                "Destination and backup arguments are the same file."));
 408                         }
 409
 410                         if (!MonoIO.ReplaceFile (fullSource, fullDest, fullBackup,
 411                                                  ignoreMetadataErrors, out error)) {
 412                                 throw MonoIO.GetException (error);
 413                         }
 414                 }
 415
 416 #if !NET_2_1
 417                 public static void SetAccessControl (string path,
 418                                                      FileSecurity fileSecurity)
 419                 {
 420                         if (null == fileSecurity)
 421                                 throw new ArgumentNullException ("fileSecurity");
 422
 423                         fileSecurity.PersistModifications (path);
 424                 }
 425 #endif
 426
 427                 public static void SetAttributes (string path,
 428                                                   FileAttributes fileAttributes)
 429                 {
 430                         MonoIOError error;
 431                         Path.Validate (path);
 432
 433                         if (!MonoIO.SetFileAttributes (path, fileAttributes, out error))
 434                                 throw MonoIO.GetException (path, error);
 435                 }
 436
 437                 public static void SetCreationTime (string path, DateTime creationTime)
 438                 {
 439                         MonoIOError error;
 440                         Path.Validate (path);
 441                         if (!MonoIO.Exists (path, out error))
 442                                 throw MonoIO.GetException (path, error);
 443                         if (!MonoIO.SetCreationTime (path, creationTime, out error))
 444                                 throw MonoIO.GetException (path, error);
 445                 }
 446
 447                 public static void SetCreationTimeUtc (string path, DateTime creationTimeUtc)
 448                 {
 449                         SetCreationTime (path, creationTimeUtc.ToLocalTime ());
 450                 }
 451
 452                 public static void SetLastAccessTime (string path, DateTime lastAccessTime)
 453                 {
 454                         MonoIOError error;
 455                         Path.Validate (path);
 456                         if (!MonoIO.Exists (path, out error))
 457                                 throw MonoIO.GetException (path, error);
 458                         if (!MonoIO.SetLastAccessTime (path, lastAccessTime, out error))
 459                                 throw MonoIO.GetException (path, error);
 460                 }
 461
 462                 public static void SetLastAccessTimeUtc (string path, DateTime lastAccessTimeUtc)
 463                 {
 464                         SetLastAccessTime (path, lastAccessTimeUtc.ToLocalTime ());
 465                 }
 466
 467                 public static void SetLastWriteTime (string path,
 468                                                      DateTime lastWriteTime)
 469                 {
 470                         MonoIOError error;
 471                         Path.Validate (path);
 472                         if (!MonoIO.Exists (path, out error))
 473                                 throw MonoIO.GetException (path, error);
 474                         if (!MonoIO.SetLastWriteTime (path, lastWriteTime, out error))
 475                                 throw MonoIO.GetException (path, error);
 476                 }
 477
 478                 public static void SetLastWriteTimeUtc (string path,
 479                                                      DateTime lastWriteTimeUtc)
 480                 {
 481                         SetLastWriteTime (path, lastWriteTimeUtc.ToLocalTime ());
 482                 }
 483
 484                 //
 485                 // The documentation for this method is most likely wrong, it
 486                 // talks about doing a "binary read", but the remarks say
 487                 // that this "detects the encoding".
 488                 //
 489                 // This can not detect and do anything useful with the encoding
 490                 // since the result is a byte [] not a char [].
 491                 //
 492                 public static byte [] ReadAllBytes (string path)
 493                 {
 494                         using (FileStream s = OpenRead (path)) {
 495                                 long size = s.Length;
 496                                 // limited to 2GB according to http://msdn.microsoft.com/en-us/library/system.io.file.readallbytes.aspx
 497                                 if (size > Int32.MaxValue)
 498                                         throw new IOException ("Reading more than 2GB with this call is not supported");
 499
 500                                 int pos = 0;
 501                                 int count = (int) size;
 502                                 byte [] result = new byte [size];
 503                                 while (count > 0) {
 504                                         int n = s.Read (result, pos, count);
 505                                         if (n == 0)
 506                                                 throw new IOException ("Unexpected end of stream");
 507                                         pos += n;
 508                                         count -= n;
 509                                 }
 510                                 return result;
 511                         }
 512                 }
 513
 514                 public static string [] ReadAllLines (string path)
 515                 {
 516                         using (StreamReader reader = File.OpenText (path)) {
 517                                 return ReadAllLines (reader);
 518                         }
 519                 }
 520
 521                 public static string [] ReadAllLines (string path, Encoding encoding)
 522                 {
 523                         using (StreamReader reader = new StreamReader (path, encoding)) {
 524                                 return ReadAllLines (reader);
 525                         }
 526                 }
 527
 528                 static string [] ReadAllLines (StreamReader reader)
 529                 {
 530                         List<string> list = new List<string> ();
 531                         while (!reader.EndOfStream)
 532                                 list.Add (reader.ReadLine ());
 533                         return list.ToArray ();
 534                 }
 535
 536                 public static string ReadAllText (string path)
 537                 {
 538                         using (StreamReader sr = new StreamReader (path)) {
 539                                 return sr.ReadToEnd ();
 540                         }
 541                 }
 542
 543                 public static string ReadAllText (string path, Encoding encoding)
 544                 {
 545                         using (StreamReader sr = new StreamReader (path, encoding)) {
 546                                 return sr.ReadToEnd ();
 547                         }
 548                 }
 549
 550                 public static void WriteAllBytes (string path, byte [] bytes)
 551                 {
 552                         using (Stream stream = File.Create (path)) {
 553                                 stream.Write (bytes, 0, bytes.Length);
 554                         }
 555                 }
 556
 557                 public static void WriteAllLines (string path, string [] contents)
 558                 {
 559                         using (StreamWriter writer = new StreamWriter (path)) {
 560                                 WriteAllLines (writer, contents);
 561                         }
 562                 }
 563
 564                 public static void WriteAllLines (string path, string [] contents, Encoding encoding)
 565                 {
 566                         using (StreamWriter writer = new StreamWriter (path, false, encoding)) {
 567                                 WriteAllLines (writer, contents);
 568                         }
 569                 }
 570
 571                 static void WriteAllLines (StreamWriter writer, string [] contents)
 572                 {
 573                         foreach (string line in contents)
 574                                 writer.WriteLine (line);
 575                 }
 576
 577                 public static void WriteAllText (string path, string contents)
 578                 {
 579                         WriteAllText (path, contents, Encoding.UTF8Unmarked);
 580                 }
 581
 582                 public static void WriteAllText (string path, string contents, Encoding encoding)
 583                 {
 584                         using (StreamWriter sw = new StreamWriter (path, false, encoding)) {
 585                                 sw.Write (contents);
 586                         }
 587                 }
 588
 589                 static DateTime? defaultLocalFileTime;
 590                 static DateTime DefaultLocalFileTime {
 591                         get {
 592                                 if (defaultLocalFileTime == null)
 593                                         defaultLocalFileTime = new DateTime (1601, 1, 1).ToLocalTime ();
 594
 595                                 return defaultLocalFileTime.Value;
 596                         }
 597                 }
 598
 599
 600                 [MonoLimitation ("File encryption isn't supported (even on NTFS).")]
 601                 public static void Encrypt (string path)
 602                 {
 603                         // MS.NET support this only on NTFS file systems, i.e. it's a file-system (not a framework) feature.
 604                         // otherwise it throws a NotSupportedException (or a PlatformNotSupportedException on older OS).
 605                         // we throw the same (instead of a NotImplementedException) because most code should already be
 606                         // handling this exception to work properly.
 607                         throw new NotSupportedException (Locale.GetText ("File encryption isn't supported on any file system."));
 608                 }
 609
 610                 [MonoLimitation ("File encryption isn't supported (even on NTFS).")]
 611                 public static void Decrypt (string path)
 612                 {
 613                         // MS.NET support this only on NTFS file systems, i.e. it's a file-system (not a framework) feature.
 614                         // otherwise it throws a NotSupportedException (or a PlatformNotSupportedException on older OS).
 615                         // we throw the same (instead of a NotImplementedException) because most code should already be
 616                         // handling this exception to work properly.
 617                         throw new NotSupportedException (Locale.GetText ("File encryption isn't supported on any file system."));
 618                 }
 619
 620 #if NET_4_0
 621                 public static IEnumerable<string> ReadLines (string path)
 622                 {
 623                         return ReadLines (File.OpenText (path));
 624                 }
 625
 626                 public static IEnumerable<string> ReadLines (string path, Encoding encoding)
 627                 {
 628                         return ReadLines (new StreamReader (path, encoding));
 629                 }
 630
 631                 // refactored in order to avoid compiler-generated names for Moonlight tools
 632                 static IEnumerable<string> ReadLines (StreamReader reader)
 633                 {
 634                         using (reader) {
 635                                 string s;
 636                                 while ((s = reader.ReadLine ()) != null) {
 637                                         yield return s;
 638                                 }
 639                         }
 640                 }
 641
 642                 public static void AppendAllLines (string path, IEnumerable<string> contents)
 643                 {
 644                         Path.Validate (path);
 645
 646                         if (contents == null)
 647                                 return;
 648
 649                         using (TextWriter w = new StreamWriter (path, true)) {
 650                                 foreach (var line in contents)
 651                                         w.WriteLine (line);
 652                         }
 653                 }
 654
 655                 public static void AppendAllLines (string path, IEnumerable<string> contents, Encoding encoding)
 656                 {
 657                         Path.Validate (path);
 658
 659                         if (contents == null)
 660                                 return;
 661
 662                         using (TextWriter w = new StreamWriter (path, true, encoding)) {
 663                                 foreach (var line in contents)
 664                                         w.WriteLine (line);
 665                         }
 666                 }
 667
 668                 public static void WriteAllLines (string path, IEnumerable<string> contents)
 669                 {
 670                         Path.Validate (path);
 671
 672                         if (contents == null)
 673                                 return;
 674
 675                         using (TextWriter w = new StreamWriter (path, false)) {
 676                                 foreach (var line in contents)
 677                                         w.WriteLine (line);
 678                         }
 679                 }
 680
 681                 public static void WriteAllLines (string path, IEnumerable<string> contents, Encoding encoding)
 682                 {
 683                         Path.Validate (path);
 684
 685                         if (contents == null)
 686                                 return;
 687
 688                         using (TextWriter w = new StreamWriter (path, false, encoding)) {
 689                                 foreach (var line in contents)
 690                                         w.WriteLine (line);
 691                         }
 692                 }
 693 #endif
 694         }
 695 }