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

   1 //------------------------------------------------------------------------------
   2 //
   3 // System.IO.Path.cs
   4 //
   5 // Copyright (C) 2001 Moonlight Enterprises, All Rights Reserved
   6 // Copyright (C) 2002 Ximian, Inc. (http://www.ximian.com)
   7 // Copyright (C) 2003 Ben Maurer
   8 //
   9 // Author:         Jim Richardson, develop@wtfo-guru.com
  10 //                 Dan Lewis (dihlewis@yahoo.co.uk)
  11 //                 Gonzalo Paniagua Javier (gonzalo@ximian.com)
  12 //                 Ben Maurer (bmaurer@users.sourceforge.net)
  13 // Created:        Saturday, August 11, 2001
  14 //
  15 //------------------------------------------------------------------------------
  16
  17 //
  18 // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
  19 //
  20 // Permission is hereby granted, free of charge, to any person obtaining
  21 // a copy of this software and associated documentation files (the
  22 // "Software"), to deal in the Software without restriction, including
  23 // without limitation the rights to use, copy, modify, merge, publish,
  24 // distribute, sublicense, and/or sell copies of the Software, and to
  25 // permit persons to whom the Software is furnished to do so, subject to
  26 // the following conditions:
  27 //
  28 // The above copyright notice and this permission notice shall be
  29 // included in all copies or substantial portions of the Software.
  30 //
  31 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  32 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  33 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  34 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  35 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  36 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  37 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  38 //
  39
  40 using System.Runtime.CompilerServices;
  41 using System.Security;
  42 using System.Security.Permissions;
  43
  44 namespace System.IO
  45 {
  46         public sealed class Path
  47         {
  48                 public static readonly char AltDirectorySeparatorChar;
  49                 public static readonly char DirectorySeparatorChar;
  50                 public static readonly char[] InvalidPathChars;
  51                 public static readonly char PathSeparator;
  52                 internal static readonly string DirectorySeparatorStr;
  53                 public static readonly char VolumeSeparatorChar;
  54
  55                 private static readonly char[] PathSeparatorChars;
  56                 private static readonly bool dirEqualsVolume;
  57
  58                 private Path ()
  59                 {
  60                 }
  61
  62                 // class methods
  63                 public static string ChangeExtension (string path, string extension)
  64                 {
  65                         if (path == null)
  66                                 return null;
  67
  68                         if (path.IndexOfAny (InvalidPathChars) != -1)
  69                                 throw new ArgumentException ("Illegal characters in path", "path");
  70
  71                         int iExt = findExtension (path);
  72
  73                         if (extension == null)
  74                                 return iExt < 0 ? path : path.Substring (0, iExt);
  75                         else if (extension == String.Empty)
  76                                 return iExt < 0 ? path + '.' : path.Substring (0, iExt + 1);
  77
  78                         else if (path.Length != 0) {
  79                                 if (extension.Length > 0 && extension [0] != '.')
  80                                         extension = "." + extension;
  81                         } else
  82                                 extension = String.Empty;
  83
  84                         if (iExt < 0) {
  85                                 return path + extension;
  86                         } else if (iExt > 0) {
  87                                 string temp = path.Substring (0, iExt);
  88                                 return temp + extension;
  89                         }
  90
  91                         return extension;
  92                 }
  93
  94                 public static string Combine (string path1, string path2)
  95                 {
  96                         if (path1 == null)
  97                                 throw new ArgumentNullException ("path1");
  98
  99                         if (path2 == null)
 100                                 throw new ArgumentNullException ("path2");
 101
 102                         if (path1 == String.Empty)
 103                                 return path2;
 104
 105                         if (path2 == String.Empty)
 106                                 return path1;
 107
 108                         if (path1.IndexOfAny (InvalidPathChars) != -1)
 109                                 throw new ArgumentException ("Illegal characters in path", "path1");
 110
 111                         if (path2.IndexOfAny (InvalidPathChars) != -1)
 112                                 throw new ArgumentException ("Illegal characters in path", "path2");
 113
 114                         //TODO???: UNC names
 115                         // LAMESPEC: MS says that if path1 is not empty and path2 is a full path
 116                         // it should throw ArgumentException
 117                         if (IsPathRooted (path2))
 118                                 return path2;
 119
 120                         char p1end = path1 [path1.Length - 1];
 121                         if (p1end != DirectorySeparatorChar && p1end != AltDirectorySeparatorChar && p1end != VolumeSeparatorChar)
 122                                 return path1 + DirectorySeparatorChar + path2;
 123
 124                         return path1 + path2;
 125                 }
 126
 127                 public static string GetDirectoryName (string path)
 128                 {
 129                         // LAMESPEC: For empty string MS docs say both
 130                         // return null AND throw exception.  Seems .NET throws.
 131                         if (path == String.Empty)
 132                                 throw new ArgumentException();
 133
 134                         if (path == null || GetPathRoot (path) == path)
 135                                 return null;
 136
 137                         CheckArgument.WhitespaceOnly (path);
 138                         CheckArgument.PathChars (path);
 139
 140                         int nLast = path.LastIndexOfAny (PathSeparatorChars);
 141                         if (nLast == 0)
 142                                 nLast++;
 143
 144                         if (nLast > 0) {
 145                                 string ret = path.Substring (0, nLast);
 146                                 int l = ret.Length;
 147                                 if (l >= 2 && ret [l - 1] == VolumeSeparatorChar)
 148                                         return ret + DirectorySeparatorChar;
 149                                 else
 150                                         return ret;
 151                         }
 152
 153                         return String.Empty;
 154                 }
 155
 156                 public static string GetExtension (string path)
 157                 {
 158                         if (path == null)
 159                                 return null;
 160
 161                         if (path.IndexOfAny (InvalidPathChars) != -1)
 162                                 throw new ArgumentException ("Illegal characters in path", "path");
 163
 164                         int iExt = findExtension (path);
 165
 166                         if (iExt > -1)
 167                         {
 168                                 if (iExt < path.Length - 1)
 169                                         return path.Substring (iExt);
 170                         }
 171                         return string.Empty;
 172                 }
 173
 174                 public static string GetFileName (string path)
 175                 {
 176                         if (path == null || path == String.Empty)
 177                                 return path;
 178
 179                         if (path.IndexOfAny (InvalidPathChars) != -1)
 180                                 throw new ArgumentException ("Illegal characters in path", "path");
 181
 182                         int nLast = path.LastIndexOfAny (PathSeparatorChars);
 183                         if (nLast >= 0)
 184                                 return path.Substring (nLast + 1);
 185
 186                         return path;
 187                 }
 188
 189                 public static string GetFileNameWithoutExtension (string path)
 190                 {
 191                         return ChangeExtension (GetFileName (path), null);
 192                 }
 193
 194                 public static string GetFullPath (string path)
 195                 {
 196                         string fullpath = InsecureGetFullPath (path);
 197                         if (SecurityManager.SecurityEnabled) {
 198                                 new FileIOPermission (FileIOPermissionAccess.PathDiscovery, fullpath).Demand ();
 199                         }
 200                         return fullpath;
 201                 }
 202
 203                 // insecure - do not call directly
 204                 internal static string InsecureGetFullPath (string path)
 205                 {
 206                         if (path == null)
 207                                 throw (new ArgumentNullException (
 208                                         "path",
 209                                         "You must specify a path when calling System.IO.Path.GetFullPath"));
 210
 211                         if (path.Trim () == String.Empty)
 212                                 throw new ArgumentException ("The path is not of a legal form", "path");
 213
 214                         if (path.Length >= 2 &&
 215                                 IsDsc (path [0]) &&
 216                                 IsDsc (path [1])) {
 217                                 if (path.Length == 2 || path.IndexOf (path [0], 2) < 0)
 218                                         throw new ArgumentException ("UNC pass should be of the form \\\\server\\share.");
 219
 220                                 if (path [0] != DirectorySeparatorChar)
 221                                         path = path.Replace (AltDirectorySeparatorChar, DirectorySeparatorChar);
 222
 223                                 return path;
 224                         }
 225
 226                         if (!IsPathRooted (path))
 227                                 path = Directory.GetCurrentDirectory () + DirectorySeparatorStr + path;
 228                         else if (DirectorySeparatorChar == '\\' &&
 229                                 path.Length >= 2 &&
 230                                 IsDsc (path [0]) &&
 231                                 !IsDsc (path [1])) { // like `\abc\def'
 232                                 string current = Directory.GetCurrentDirectory ();
 233                                 if (current [1] == VolumeSeparatorChar)
 234                                         path = current.Substring (0, 2) + path;
 235                                 else
 236                                         path = current.Substring (0, current.IndexOf ('\\', current.IndexOf ("\\\\") + 1));
 237                         }
 238                         return CanonicalizePath (path);
 239                 }
 240
 241                 static bool IsDsc (char c) {
 242                         return c == DirectorySeparatorChar || c == AltDirectorySeparatorChar;
 243                 }
 244
 245                 public static string GetPathRoot (string path)
 246                 {
 247                         if (path == null)
 248                                 return null;
 249
 250                         if (path == String.Empty)
 251                                 throw new ArgumentException ("This specified path is invalid.");
 252
 253                         if (!IsPathRooted (path))
 254                                 return String.Empty;
 255
 256                         if (DirectorySeparatorChar == '/') {
 257                                 // UNIX
 258                                 return IsDsc (path [0]) ? DirectorySeparatorStr : String.Empty;
 259                         } else {
 260                                 // Windows
 261                                 int len = 2;
 262
 263                                 if (path.Length == 1 && IsDsc (path [0]))
 264                                         return DirectorySeparatorStr;
 265                                 else if (path.Length < 2)
 266                                         return String.Empty;
 267
 268                                 if (IsDsc (path [0]) && IsDsc (path[1])) {
 269                                         // UNC: \\server or \\server\share
 270                                         // Get server
 271                                         while (len < path.Length && !IsDsc (path [len])) len++;
 272                                         // Get share
 273                                         while (len < path.Length && !IsDsc (path [len])) len++;
 274                                         return DirectorySeparatorStr +
 275                                                 DirectorySeparatorStr +
 276                                                 path.Substring (2).Replace (AltDirectorySeparatorChar, DirectorySeparatorChar);
 277                                 } else if (IsDsc (path [0])) {
 278                                         // path starts with '\' or '/'
 279                                         return DirectorySeparatorStr;
 280                                 } else if (path[1] == VolumeSeparatorChar) {
 281                                         // C:\folder
 282                                         if (path.Length >= 3 && (IsDsc (path [2]))) len++;
 283                                 } else
 284                                         return Directory.GetCurrentDirectory ().Substring (0, 2);// + path.Substring (0, len);
 285                                 return path.Substring (0, len);
 286                         }
 287                 }
 288
 289                 // FIXME: Further limit the assertion when imperative Assert is implemented
 290                 [FileIOPermission (SecurityAction.Assert, Unrestricted = true)]
 291                 public static string GetTempFileName ()
 292                 {
 293                         FileStream f = null;
 294                         string path;
 295                         Random rnd;
 296                         int num = 0;
 297
 298                         rnd = new Random ();
 299                         do {
 300                                 num = rnd.Next ();
 301                                 num++;
 302                                 path = Path.Combine (GetTempPath(), "tmp" + num.ToString("x"));
 303
 304                                 try {
 305                                         f = new FileStream (path, FileMode.CreateNew);
 306                                 }
 307                                 catch (SecurityException) {
 308                                         // avoid an endless loop
 309                                         throw;
 310                                 }
 311                                 catch {
 312                                 }
 313                         } while (f == null);
 314
 315                         f.Close();
 316                         return path;
 317                 }
 318
 319                 [EnvironmentPermission (SecurityAction.Demand, Unrestricted = true)]
 320                 public static string GetTempPath ()
 321                 {
 322                         string p = get_temp_path ();
 323                         if (p.Length > 0 && p [p.Length - 1] != DirectorySeparatorChar)
 324                                 return p + DirectorySeparatorChar;
 325
 326                         return p;
 327                 }
 328
 329                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
 330                 private static extern string get_temp_path ();
 331
 332                 public static bool HasExtension (string path)
 333                 {
 334                         if (path == null || path.Trim () == String.Empty)
 335                                 return false;
 336
 337                         int pos = findExtension (path);
 338                         return 0 <= pos && pos < path.Length - 1;
 339                 }
 340
 341                 public static bool IsPathRooted (string path)
 342                 {
 343                         if (path == null || path.Length == 0)
 344                                 return false;
 345
 346                         if (path.IndexOfAny (InvalidPathChars) != -1)
 347                                 throw new ArgumentException ("Illegal characters in path", "path");
 348
 349                         char c = path [0];
 350                         return (c == DirectorySeparatorChar     ||
 351                                 c == AltDirectorySeparatorChar  ||
 352                                 (!dirEqualsVolume && path.Length > 1 && path [1] == VolumeSeparatorChar));
 353                 }
 354
 355                 // private class methods
 356
 357                 private static int findExtension (string path)
 358                 {
 359                         // method should return the index of the path extension
 360                         // start or -1 if no valid extension
 361                         if (path != null){
 362                                 int iLastDot = path.LastIndexOf ('.');
 363                                 int iLastSep = path.LastIndexOfAny ( PathSeparatorChars );
 364
 365                                 if (iLastDot > iLastSep)
 366                                         return iLastDot;
 367                         }
 368                         return -1;
 369                 }
 370
 371                 static Path () {
 372                         VolumeSeparatorChar = MonoIO.VolumeSeparatorChar;
 373                         DirectorySeparatorChar = MonoIO.DirectorySeparatorChar;
 374                         AltDirectorySeparatorChar = MonoIO.AltDirectorySeparatorChar;
 375
 376                         PathSeparator = MonoIO.PathSeparator;
 377                         InvalidPathChars = MonoIO.InvalidPathChars;
 378
 379                         // internal fields
 380
 381                         DirectorySeparatorStr = DirectorySeparatorChar.ToString ();
 382                         PathSeparatorChars = new char [] {
 383                                 DirectorySeparatorChar,
 384                                 AltDirectorySeparatorChar,
 385                                 VolumeSeparatorChar
 386                         };
 387
 388                         dirEqualsVolume = (DirectorySeparatorChar == VolumeSeparatorChar);
 389                 }
 390
 391
 392                 static string CanonicalizePath (string path) {
 393
 394                         // STEP 1: Check for empty string
 395                         if (path == null) return path;
 396                         if (Environment.IsRunningOnWindows)
 397                                 path = path.Trim ();
 398
 399                         if (path == String.Empty) return path;
 400
 401                         // STEP 2: Check to see if this is only a root
 402                         string root = GetPathRoot (path);
 403                         // it will return '\' for path '\', while it should return 'c:\' or so.
 404                         // Note: commenting this out makes the ened for the (target == 1...) check in step 5
 405                         //if (root == path) return path;
 406
 407                         // STEP 3: split the directories, this gets rid of consecutative "/"'s
 408                         string [] dirs = path.Split (DirectorySeparatorChar, AltDirectorySeparatorChar);
 409                         // STEP 4: Get rid of directories containing . and ..
 410                         int target = 0;
 411
 412                         for (int i = 0; i < dirs.Length; i++) {
 413                                 if (dirs [i] == "." || (i != 0 && dirs [i] == String.Empty)) continue;
 414                                 else if (dirs [i] == "..") {
 415                                         if (target != 0) target--;
 416                                 }
 417                                 else
 418                                         dirs [target++] = dirs [i];
 419                         }
 420
 421                         // STEP 5: Combine everything.
 422                         if (target == 0 || (target == 1 && dirs [0] == ""))
 423                                 return root;
 424                         else {
 425                                 string ret = String.Join (DirectorySeparatorStr, dirs, 0, target);
 426                                 switch (DirectorySeparatorChar) {
 427                                 case '\\': // Windows
 428                                         // In GetFullPath(), it is assured that here never comes UNC. So this must only applied to such path that starts with '\', without drive specification.
 429                                         if (path [0] != DirectorySeparatorChar && path.StartsWith (root)) {
 430                                                 if (ret.Length <= 2 && !ret.EndsWith (DirectorySeparatorStr)) // '\' after "c:"
 431                                                         ret += DirectorySeparatorChar;
 432                                                 return ret;
 433                                         } else {
 434                                                 string current = Directory.GetCurrentDirectory ();
 435                                                 if (current.Length > 1 && current [1] == VolumeSeparatorChar) {
 436                                                         // DOS local file path
 437                                                         if (ret.Length == 0 || IsDsc (ret [0]))
 438                                                                 ret += '\\';
 439                                                         return current.Substring (0, 2) + ret;
 440                                                 }
 441                                                 else if (IsDsc (current [current.Length - 1]) && IsDsc (ret [0]))
 442                                                         return current + ret.Substring (1);
 443                                                 else
 444                                                         return current + ret;
 445                                         }
 446                                 default: // Unix/Mac
 447                                         return ret;
 448                                 }
 449                         }
 450                 }
 451         }
 452 }